Primary angle-closure glaucoma: clinical guidelines

List of Abbreviations

AGO – antiglaucoma surgery

BB – beta-blockers

AH – aqueous humor

IOP – intraocular pressure

AQH – aqueous humor

RGC – retinal ganglion cells

ONH – optic nerve head

MG – malignant glaucoma

ACG – angle-closure glaucoma

CAI – carbonic anhydrase inhibitors

ITC – iridotrabecular contact

LGP – laser gonioplasty

LI – laser iridotomy/iridectomy

Med – medication

ICD-10 – International Classification of Diseases 10th Revision

NRR – neuroretinal rim

OCT – optical coherence tomography

APAC – acute primary angle-closure

COS – corneal optical section

VF – visual field

AL – axial length of the eye

PAC – primary angle-closure

PACG – primary angle-closure glaucoma

AC – anterior chamber

PACS – primary angle-closure suspect

PAS – peripheral anterior synechiae

POAG – primary open-angle glaucoma

COR – cornea-iris distance

SAP – standard automated perimetry

RNFL – retinal nerve fiber layer

vitreous body

TR – trabeculectomy

ACA – anterior chamber angle

phaco – phacoemulsification

CB – ciliary body

CCT – central corneal thickness

P₀ – tonometry index when measuring IOP using most modern methods

Pt – tonometry index measured with a Maklakov applanation tonometer using a 10g weight.

Terms and Definitions

Ocular biomicroscopy is an in vivo visual examination method of the optical media and ocular tissues based on creating contrast between illuminated and non-illuminated areas, performed using a slit lamp and additional diagnostic lenses (specifically, for fundus biomicroscopy).

Glaucomatous optic neuropathy (GON) is an axonopathy in which visual pathway damage is caused by injury to retinal ganglion cell axons as they exit the eyeball at the optic nerve head (ONH).

Intraocular pressure (IOP) is the fluid pressure inside the eye that maintains the shape of the eyeball and ensures a constant supply of circulating nutrients and normal trophic state of intraocular tissues.

Gonioscopy is a visual examination method of the anterior chamber angle (ACA) performed using a slit lamp and a gonioscope (goniolens).

Target pressure is the maximum allowable intraocular pressure at which the disease progresses slowly enough that vision-related quality of life remains at a sufficiently high level throughout the patient's life.

Van Herick method is an examination method performed during biomicroscopy to determine the likelihood of ACA closure. The test allows for an indirect assessment of the ACA and cannot serve as an alternative to gonioscopy. The corneal periphery is illuminated with a narrow light slit at an angle of 60⁰ as close to the limbus as possible. The light strip of the corneal optical section, the light strip on the iris surface, and the distance from the inner surface of the cornea to the iris are visualized. The width of the anterior chamber angle is judged by the ratio of the corneal optical section (COS) thickness to the cornea-iris distance (COR). A COS-to-COR ratio of 1:1 indicates a low probability of a narrow ACA of 35-45^o; 1:1/2 indicates a low probability of a narrow ACA of 20-45^o; 1:1/4 indicates the possibility of a narrow ACA of 20^o; 1:less than ¼ indicates the possibility of a closed ACA of 10^o; 1:0 indicates a closed ACA of 0^o.

Neuroretinal rim (NRR) is the area between the optic disc margin and the margin of its cup, where the bulk of retinal ganglion cell axons are concentrated.

Optical coherence tomography (OCT) is a non-invasive diagnostic method for in vivo visualization, qualitative and quantitative analysis of morphological features of fundus structures, based on the principle of light interferometry.

Ophthalmodynamometry / Ophthalmotonometry is an indirect method for measuring intraocular pressure; the value of the ocular tone during tonometry is determined by analyzing eye deformation data obtained with a tonometer and evaluated in millimeters of mercury (mmHg).

Forbes test is a gonioscopy method with compression. During the examination, the central part of the cornea is pressed with the gonioscope, displacing the anterior chamber fluid to the periphery and pushing the root of the iris backward. The Forbes test is positive if a large part of the filtration zone opens upon indentation. The Forbes test is negative if the iris root is not displaced upon indentation due to extensive synechiae.

Standard automated perimetry (SAP) is computer-based static perimetry that examines light sensitivity in the central visual field using a white stimulus on a white background.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Primary angle-closure glaucoma (PACG) is a disease in which elevated intraocular pressure (IOP) is caused by obstructed aqueous humor (AH) outflow due to partial or complete blockade of the ACA by the iris root, accompanied by the following signs [1,2]:

• periodic or constant elevation of IOP levels;

• optic nerve atrophy (with excavation);

• characteristic visual field (VF) changes;

• closed iridocorneal angle.

The term "glaucoma" is used when there are signs of glaucomatous optic neuropathy. In angle closure without signs of optic nerve damage, the terms "suspected primary angle closure" and "primary angle closure" are recommended [3, 4].

Suspected primary angle closure (SPAC) – a condition characterized by apposition between the iris and the trabecular meshwork (ITM contact) in two or more quadrants, without peripheral anterior synechiae (PAS), elevated IOP, or signs of optic nerve damage.

Primary angle closure (PAC) – a condition characterized by ITM contact in two or more quadrants with the development of PAS, and/or elevated IOP without signs of optic nerve damage.

Acute primary angle-closure glaucoma (APACG) – a condition characterized by sudden and complete closure of the iridocorneal angle, a sharp increase in IOP, which can lead to vision loss if emergency treatment is not provided.

1.2 Etiology and pathogenesis of the disease or condition (group of diseases or conditions)

In APACG, angle closure can be caused by various mechanisms in predisposed eyes. APACG must be differentiated from secondary angle-closure glaucoma (ACG), in which the angle is closed by the iris due to other conditions (uveitis, neovascular glaucoma secondary to diabetes and central retinal vein occlusion, iridocorneal endothelial syndrome, phacomorphic glaucoma, nanophthalmos, lens subluxation, posterior segment tumors, etc.) [1, 3, 4].

Congenital, acquired, and demographic risk factors for APACG are distinguished [1, 3, 4].

Congenital factors include:

• shallow anterior chamber (less than 2.5 mm);

• narrow angle profile;

• short axial length of the eye;

• large anteroposterior lens thickness;

• small corneal diameter;

• flat corneal curvature;

• refraction (hyperopic refraction is frequently combined with a narrow angle);

• anterior position of the ciliary body;

• brown iris color.

Acquired risk factors:

• age-related increase in lens volume;

• age-related flattening of the iris;

• age-related atrophy of the iris root;

• fluid accumulation in the posterior vitreous;

• use of certain medications in individuals predisposed to angle closure.

Demographic risk factors:

• age (manifests on average around 60 years; prevalence increases with age) [6, 7];

• female gender (women are affected more frequently than men in a 4:1 ratio) [8];

• race (more common in indigenous populations of Southeast Asia, China, and Inuit populations) [9, 10];

• family history (first-degree relatives have an increased risk due to inherited anatomical predisposing factors) [11, 12].

Closure (blockade) of the iridocorneal angle by the iris root plays the primary role in the pathogenesis of APACG. Based on the leading mechanism of angle closure there are four main forms of APACG: pupillary block, plateau iris, creeping, and vitreolenticular block (malignant).

The predominant mechanism of primary angle closure in approximately 80–90% of patients is relative pupillary block. Relative pupillary block can occur in eyes with any type of refraction, but is more common in hyperopia, where the depth and volume of the anterior chamber are smaller and the iris-lens contact in the pupillary zone is tighter than in emmetropia. Age-related increase in the axial thickness of the lens shifts its anterior surface closer to the cornea, while equatorial growth weakens the zonular fibers, allowing the iridolenticular diaphragm to move forward. Both factors lead to gradual progressive narrowing of the anterior chamber. Pupil dilation (4–6 mm) impedes aqueous humor outflow from the posterior to the anterior chamber, which increases relative pupillary block. The pressure gradient between the eye chambers further enhances iris adhesion to the angle, subsequently leading to the formation of peripheral anterior synechiae (goniosynechiae) [1, 2, 3, 4].

APACG with plateau iris is rare. In this case, the iris has a flat profile, excessive thickness at the root ("rolls"), and lies adjacent to the trabecular meshwork. Upon pupil dilation, the iris "bunches up" against the angle and closes the recess. It is more common in young Asian myopes.

Plateau iris configuration features an abnormally anterior position of the ciliary processes. Following iridectomy, the iris does not pull away from the angle because it is held forward by the ciliary processes; this condition is referred to as plateau iris syndrome [1, 3, 4].

APACG with shortened angle ("creeping" glaucoma) is considered by foreign authors within the scope of "plateau iris configuration" because the cause is the anterior position of the ciliary processes and sometimes a "flat" iris architecture. In domestic literature, it is singled out separately. It is characterized by progressive, creeping synechial closure of the iridocorneal angle. The process starts superiorly and spreads circumferentially. IOP typically rises when more than half of the angle is occluded. It remains unclear whether "creeping glaucoma" is a consequence of undetected transient angle closure or chronic miotic therapy [2].

Vitreolenticular block — "malignant glaucoma" (MG) is a rare, yet clinically severe form with a poor prognosis. Risk factors for MG include axial hyperopia, female gender, microphthalmos, nanophthalmos, anterior microphthalmos, ACG with high IOP, long-term miotic use, and postoperative uveitis with exudation. In these cases, most frequently in young or middle-aged women, the ciliary processes contact the lens equator, altering the direction of aqueous flow into the vitreous body (VB) and creating additional fluid pockets within it. Aqueous humor accumulates in the posterior segment of the eye, causing the VB and lens to shift anteriorly, completely blocking the iridocorneal angle. It can develop in phakic eyes as well as aphakic and pseudophakic eyes, following laser or surgical interventions, and in eyes with a very shallow anterior chamber and hyperopia [13-15].

1.3 Epidemiology of the Disease or Condition

Primary glaucoma is one of the leading causes of blindness worldwide. The World Health Organization considers glaucoma the second most common cause of blindness after cataracts. Primary angle-closure glaucoma (PACG) accounts for nearly half of all glaucoma-related blindness globally [16].

The number of people with glaucoma worldwide in 2010 was approximately 60.5 million, of whom 15.7 million suffered from PACG. Projections indicate that by 2020 the number of primary glaucoma patients will increase to 80 million, with 21 million diagnosed with PACG, and 5.3 million potentially becoming blind from the disease [17].

Epidemiology and population screening issues in primary angle-closure glaucoma (PACG) differ significantly from the epidemiological and ethnic characteristics of primary open-angle glaucoma (POAG) [9].

Ethnicity is one of the main factors determining predisposition to primary angle closure (PAC). Population studies show that PAC is more prevalent among individuals of Asian descent than European descent. Recent data indicate a high prevalence of PACG among the population of India [18-21], East Asian populations outside of China [22-25], in China [26, 27], and in Southeast Asian countries [28].

Among individuals aged 40 years and older, the prevalence of PAC ranges from 0.1% in Europeans to 1.4% in Asians [26, 29] and up to 5% in Greenlandic Inuit [9].

In the European population over 40 years of age, the prevalence of PACG is 0.4%. Three-quarters of the patients are women. There are 1.6 million PACG patients in Europe and 581,000 in the USA [30].

According to federal statistical reporting in the Russian Federation, a total of about 1.3 million patients with primary glaucoma were registered in 2023 [31]. The prevalence of PACG in Russia is about 15–40%, but exceeds 80% in patients of Asian descent. The disease is diagnosed three times more frequently in women.

1.4 Features of Coding the Disease or Condition

Glaucoma (H40)

H40.2 – Primary angle-closure glaucoma

1.5 Classification of the disease or condition

In routine clinical practice, PACG is classified according to the following criteria [2]:

• by the mechanism of angle closure:

- relative pupillary block;

- plateau iris;

- "creeping glaucoma";

- vitreolenticular block (malignant glaucoma)

• by clinical course [2]:

- acute angle-closure glaucoma attack;

- intermittent (subacute) angle-closure glaucoma;

- chronic angle-closure glaucoma

• by primary angle closure stage (Table 1)

- suspected primary angle closure

- primary angle closure

- primary angle-closure glaucoma

Table 1.

Classification of primary angle closure by stages

Depending on the severity of the pathological process, IOP level, and disease course, PACG is classified similarly to primary open-angle glaucoma (POAG) [2].

• by severity of the pathological process:

- early-stage glaucoma;

- moderate-stage glaucoma;

- advanced-stage glaucoma;

- terminal-stage glaucoma

• by disease course:

- stabilized – absence of negative dynamics in the state of the optic disc (OD) and visual field (VF) during prolonged patient follow-up (at least 6 months)

- non-stabilized – repeated examinations reveal negative dynamics of structural (OD, retinal nerve fibers) and functional (VF) parameters.

• by IOP level:

A ‒ IOP within normal limits (P₀ < 22 mm Hg, Pt < 25 mm Hg);

B ‒ moderately elevated IOP (from 22 ≤ P₀ ≤ 28 mm Hg, Pt – 26–32 mm Hg);

C ‒ high IOP (P₀ ≥ 29 mm Hg, Pt ≥33 mm Hg).

The division of the continuous glaucomatous process into stages based on the state of the OD and visual field, determined using kinetic perimetry, is conventional (Table 2).

Table 2.

For the diagnosis of glaucoma stages, it is important not only to determine the transition from one stage to another, but also to identify and quantify disease progression. This requires classifications that use functional parameters (perimetric global indices obtained via standard automated perimetry) (Table 3) [32, 33].

Table 3.

Classification of glaucoma stages according to static perimetry data

VF examination is performed using a Humphrey Field Analyzer 3 (HFA3) automated perimeter or its equivalents.

1.6 Clinical presentation of the disease or condition

The clinical presentation of PACG depends on the angle closure mechanism and the course of the disease [1-4].

Relative pupillary block – on biomicroscopy, the anterior chamber is generally shallower than average depth. On gonioscopy, depending on the stage of the process, partial or complete closure of the anterior chamber angle (ACA) is revealed. To determine functional or organic ACA blockade, the Forbes compression test is used.

Platypoeia / Plateau iris – on biomicroscopy, the anterior chamber is of medium depth; however, the iris root has excessive thickness ("rolls", Fuchs' crypts/folds) and is positioned opposite the trabecular meshwork. According to ultrasound biomicroscopy in plateau iris configuration, there is a predominantly anterior position of the ciliary body processes, due to which, after iridectomy, the iris does not detach from the ACA.

"Creeping" glaucoma – on gonioscopy, the anterior chamber angle is shortened circumferentially, though unevenly across different sectors. The iris originates not from the ciliary body, but from the scleral spur or trabecular meshwork at varying levels depending on the height of the goniosynechiae. IOP usually rises when more than half of the angle is obstructed. The course is generally chronic, but there may be episodes resembling a subacute course of PACG.

Vitreolenticular block or malignant glaucoma (MG) – the diagnosis of MG is often made late, largely due to the low incidence of the disease, as well as due to similarities with certain other pathological conditions. MG has characteristic clinical features. Due to the anterior shift of the iris-lens diaphragm in MG, myopic refraction increases. MG following antiglaucoma surgery is characterized by the absence of a filtering bleb in the absence of external filtration due to conjunctival suture failure confirmed by the fluorescein test. The anterior chamber is shallow to slit-like throughout or absent even in the presence of an iridectomy. With long-standing corneo-lenticular contact, anterior synechiae and corneal decompensation develop. IOP increases rapidly or gradually as the ACA closes. IOP elevation can also occur against the background of an actively functioning filtering bleb. Administration of conventional hypotensive therapy does not lower intraocular pressure, however, the administration of mydriatic and cycloplegic agents may yield a positive effect. On biomicroscopy, if the optical media of the eye are transparent, free zones or demarcated cavities where aqueous humor accumulates can be seen in the vitreous body. In aphakic eyes, contact of the ciliary processes with the anterior surface of the vitreous body is visualized. In aphakic and pseudophakic eyes with MG, high density of the hyaloid membrane is noted due to its total obliteration with the posterior chamber of the eye. Ultrasound echography in MG allows determining the anteroposterior axial length of the eye (often less than 22 mm), the state of the ciliary body and processes (size, location), and determining the state of the ocular tunics and choroidal thickness. Ultrasound scanning of the anterior segment allows determining the mutual arrangement of the posterior chamber, iris, ciliary body, lens, anterior surface of the vitreous body, as well as detecting anterior rotation of the ciliary processes and additional cavities in the vitreous body.

Acute primary angle-closure glaucoma attack. Precipitating factors for an acute attack include drug-induced mydriasis, emotional stress, staying in a dark room, working with the head tilted, accommodation strain, and hypothermia. Characteristic patient complaints include headache, nausea (rarely vomiting), eye pain, blurred vision, and halos around lights. IOP is high; biomicroscopy reveals conjunctival hyperemia, corneal edema, iris edema, a shallow anterior chamber, aqueous humor losing its clarity (due to protein exudation), and a dilated pupil that often becomes irregularly shaped and unresponsive to light. Due to the rapid rise in intraocular pressure and significant compression of the iris root in the corneoscleral zone, a segmental blood flow disturbance occurs in the radial vessels with signs of necrosis and aseptic inflammation. Clinically, this manifests as posterior synechiae along the pupillary margin and the appearance of goniosynechiae. Following the resolved attack, focal iris atrophy, pupil deformation, and displacement persist. Lenticular opacities are detected as white spots located predominantly in the anterior and middle subcapsular layers. Corneal edema hinders the examination of fundus details, yet an edematous optic disc and dilated retinal veins can be observed; in some cases, hemorrhages in the optic disc area and paracentral retinal areas are present. After corneal edema subsides, gonioscopy helps determine the state of the iridocorneal angle. Uveal, neovascular, and other secondary angle-closure glaucomas can present acutely, mimicking a primary acute attack. For differential diagnosis, it is important to perform gonioscopy on the fellow eye: if the iridocorneal angle is open there, it is not an acute attack. Forbes compression gonioscopy will help locate an area of open iridocorneal angle where laser iridotomy can be performed.

Intermittent primary angle-closure glaucoma (PACG). Characterized by periodic, mild ocular pain and blurred vision. Patient complaints may be vague, intensifying by evening and subsiding in the morning (presumably because the pupil constricts during sleep and IOP decreases). If there are complaints of colored halos (monochromatic in cataracts), this may indicate periodic corneal edema. Therefore, even if elevated IOP is not present at the time of examination, gonioscopy is recommended.

The clinical symptoms of glaucoma optic neuropathy (GON) in the chronic course of PACG, just as in POAG, begin with the enlargement of the physiological cup. Gradually, there is a "breakthrough" of the neuroretinal rim (NRR) toward the optic nerve margin, and atrophy of the choroid around it. In the late stage, the cupping becomes total and deep. GON is also characterized by focal lesions of the retinal nerve fiber layer (RNFL), vertical enlargement of cupping, cup/disc asymmetry, and optic disc hemorrhages [1, 2].

Optical coherence tomography (OCT) is used for qualitative and quantitative assessment of optic disc, RNFL, and inner retinal layer parameters in the macular area. GON is characterized by a progressive decrease in RNFL thickness combined with narrowing of the NRR, most commonly in the inferotemporal and superotemporal sectors of the optic disc [34].

Perimetry makes it possible to detect changes in visual functions that are not determined by visual acuity testing (this is a subjective method; reliability is achieved through repeated measurements over time). Perimetry is used to determine, localize, and quantify the degree of visual field loss. Both diffuse and focal visual field changes are characteristic. In the early stage of the disease, enlargement of the blind spot, focal lesions (scotomas) in the paracentral area—especially frequently in Bjerrum's area—are typical; in rare cases, defects may occur in the periphery of the temporal visual field. As the disease develops, arcuate scotomas merging with the blind spot, nasal steps, and constriction of peripheral boundaries to tubular and residual visual fields may appear. Progression of visual field defects is characterized by: the presence of a new defect in a previously normal area, deepening of a preexisting defect, enlargement of a preexisting scotoma to adjacent points, and the presence of a generalized decrease in sensitivity.

2. Diagnostics, medical indications and contraindications for diagnostic methods

To determine a treatment strategy aimed at preserving the patient's vision and quality of life, of particular importance are the ability to accurately diagnose PACG, assess the development mechanism, stage, and stabilization of the disease, as well as timely examination of patients at risk to prevent further closure of the iridocorneal angle and the development of an acute attack.

Criteria for establishing the disease or condition

• periodic or permanent increase in IOP above the individual norm;

• structural pathological changes of the optic disc and RNFL;

• typical visual field defects corresponding to damage to the optic disc and RNFL;

• closed iridocorneal angle (confirmed by gonioscopy).

2.1 Complaints and Anamnesis

Comments: most often, in PAC and the chronic course of PACG, complaints may be absent. Characteristic complaints for the acute and intermittent course of the disease include: pain in the eye and the corresponding half of the head, eye redness, blurred vision, halos around light sources, less frequently nausea and/or vomiting, palpitations, and cramping abdominal pain.

Comments: one should ascertain the presence of PACG cases among close relatives, previous eye diseases, surgical interventions or injuries, use of drugs precipitating an acute attack (mydriatics and cycloplegics, psychoanaleptics [code N06] and their subgroups—antidepressants [N06A], centrally acting sympathomimetics [N06BA], antiparkinsonian drugs—central anticholinergics [N04A anticholinergic agents], antipsychotics [N05A psycholeptics], antihistamines for systemic use [R06]), visual work in poor lighting, prolonged work with the head tilted, hypothermia, drug allergies, smoking and alcohol/drug use, and the presence of concomitant systemic diseases [45-48]. To systematize the obtained data, the «Glaucoma Suspect Questionnaire» and «Questionnaire for Identifying Glaucoma Risk Factors» presented in Appendix G1-G2 may be used.

2.2 Physical Examination

Physical examination is not performed for the diagnosis of PACG.

2.3 Laboratory Diagnostics

There are no diagnostic criteria for PACG based on clinical laboratory test data.

2.4 Instrumental Diagnostics

Comments: vision should be tested without pupil dilation and with the best correction at distance and near. Late-stage glaucoma can affect not only peripheral but also central vision. In an acute attack of angle-closure glaucoma, visual acuity is sharply reduced.

Comments: PAC and PACG are more often combined with hyperopia, except for the "plateau" iris configuration, where myopic refraction is predominantly encountered. The study is performed using autorefractometers or by retinoscopy, determining the lowest negative or positive lens with which maximum visual acuity is achieved. Neutralization of any refractive error is crucial for accurate computerized perimetry.

Comments: IOP measurement must be performed before gonioscopy. It is recommended to perform multiple IOP measurements, recording the time of the procedure, which can be important for identifying diurnal fluctuations and selecting drug therapy [53-56]. The total number of measurements should generally be at least 3 morning and 3 evening measurements. They can be performed discretely, with a break of a week or 10 days; special chronobiological regimens can also be used [2].

Comments: Biomicroscopic changes in ocular media and structures are described in Section 1.6. Biomicroscopy of the anterior segment using the Van Herick method can be used to determine the probability of angle closure, though it does not replace gonioscopy. The corneal periphery is illuminated with a narrow light slit at an angle of 60⁰ as close to the limbus as possible. The light beam of the optical section of the cornea, the light band on the iris surface, and the distance from the inner surface of the cornea to the iris are visualized. The width of the anterior chamber angle is judged by the ratio of the corneal optical section thickness (OST) to the cornea-iris distance (CID). Based on the OST-to-CID ratio: 1:1 indicates a low probability of a narrow angle (35-45⁰), 1:2 indicates a low probability of a narrow angle (20-45⁰), 1:1.4 (1:1/4) indicates the possibility of a narrow angle (20⁰), 1:less than 1/4 indicates the possibility of a closed angle (10⁰), and 1:0 indicates a closed angle (0⁰) [1, 2, 4].

Comments: Gonioscopy must be performed on both eyes. Proper positioning of the ophthalmic lens (gonioscope) is essential, especially during compression, to obtain a true picture of the anterior chamber angle. Gonioscopy is performed in a dark room using a short light beam (about 1 mm) on a slit lamp, avoiding light entering the pupil area, which can widen the angle. When corneal edema occurs during an acute glaucoma attack, gonioscopy is difficult; in this case, assessing the condition of the angle in the fellow eye is important for differential diagnosis. Spaeth, Shaffer, or Kanski classifications can be used to assess gonioscopy results [2, 60-62].

Comments: Pupil dilation for a detailed examination of the fundus is recommended after iridectomy. In the absence of iridectomy, fundus examination with a dilated pupil using mydriatic and cycloplegic agents is possible, provided the pupil is subsequently constricted under medical supervision to eliminate the potential risk of an acute glaucoma attack. When performing fundus biomicroscopy, non-contact diagnostic ophthalmic lenses for indirect ophthalmoscopy are used (to obtain a stereoscopic image).

Comments: In modern glaucoma diagnosis, perimetry remains an essential and mandatory research method for diagnosing, monitoring, and treating patients. In the early and moderate stages of PACG, it is advisable to perform standard automated perimetry (SAP) (threshold programs within 30, 24, 10º with a standard white stimulus); in the advanced stage, an acceptable alternative may be Goldman perimetry to determine the peripheral borders of the visual field, or the use of tests intended for low visual acuity with a stimulus larger than the standard size. For a more accurate assessment of visual field progression in a patient, it is preferable to use the same type of device and test. An important condition for correctly determining visual field borders is preliminary patient instruction on perimetry, as well as refraction correction prior to testing. Various indices, as well as different diagnostic tests confirming the results of computer progression analysis during dynamic testing, are used to evaluate SAP results [66, 67].

2.5 Other Procedures

Comments: the mean CCT value is 540±30 µm. Patients with a CCT of more than 580 µm require downward correction. Patients with a CCT of less than 520 µm require upward correction of tonometric values [57-60].

Comments: OCT is performed additionally for the quantitative assessment of the optic disc, retinal nerve fiber layer (RNFL), and inner macular layers. OCT visualization results are presented in three categories: "within normal limits", "borderline", and "outside normal limits"– and cannot serve as a clinical diagnosis. These are statistical data representing the results of comparing the patient's parameters with the device's normative database. The obtained results must be compared with the clinical picture to avoid false conclusions, especially in cases of non-standard, atypical optic disc variants whose parameters are absent from the database. The initial OCT examination is of key importance, and its high quality is essential, since subsequent progression assessment is carried out by comparison with the baseline image. The frequency of repeat examinations depends on the rate of progression: in cases of high progression risk, it is performed three months after the initial examination, and in other cases, once every 6 months.

Comments: determination of the eye's AL is possible using an ultrasound or optical biometer. An AL of less than 20-21 mm is considered a risk factor for PACG development. It is also possible to determine anterior chamber depth: in vitreolenticular block and nanophthalmos, the anterior chamber is shallow or slit-like; in pupillary block, it is ≤ 2.0 mm; and in "plateau iris", it is ≥ 2.5 mm.

Comments: Instrumental evaluation of the anterior chamber angle configuration and quantitative assessment of anterior segment structures, including for differential diagnosis, can be performed using ultrasound scanning and anterior segment OCT. Ultrasound scanning allows real-time morphological evaluation of the anterior segment at a depth of up to 5 mm; the technique is contact-based, but unlike OCT, it allows the assessment of ocular structures behind the iris. In OCT examination, the wavelength of the infrared spectrum allows scans to be obtained through the cornea and sclera up to the pigment epithelium of the iris; the technique can be used to evaluate the results of provocative tests, and its non-invasiveness is considered an advantage.

3. Treatment, including drug and non-drug therapies, diet therapy, and pain management

The treatment method is determined by the cause of angle closure, and since it is most commonly caused by functional pupillary block, the primary recommendation for all patients is laser iridotomy (LI). In patients with PAC or PACG, conservative treatment should not be used as a substitute for laser or surgical iridotomy [1, 4, 82].

3.1 Conservative Treatment

Comments. Medical treatment of primary angle-closure suspect (PACS) is initiated immediately upon confirming the diagnosis. Pilocarpine** 1% at 1-2 drops 1-2 times daily is prescribed prior to laser iridotomy (LI) to prevent acute angle closure. Prolonged use of pilocarpine may lead to increased pupillary block, persistent miosis, and the development of posterior synechiae. Continuous administration of 1% pilocarpine** in PACS patients is permissible if there is residual angle closure after LI, and in cases where other groups of antiglaucoma medications and miotics fail to lower IOP to the target pressure. Prescribing 1% pilocarpine to PACS patients with axial hyperopia, microphthalmia, or a mismatch between the axial length and lens thickness may lead to angle closure [82, 85].

The mechanism of action, side effects, and contraindications for parasympathomimetics are presented in Table 4.

Table 4.

Characteristics of the parasympathomimetic pharmacological group

Comments. Prescription of all groups of antiglaucoma drugs and miotics is possible, taking into account contraindications (beta-blockers (BBs), carbonic anhydrase inhibitors (CAIs), sympathomimetics for glaucoma treatment, prostaglandin analogues (PGAs)). The daily dose and duration of treatment are determined by the physician depending on the IOP level. The use of antiglaucoma drugs and miotics is possible in combination with each other, as well as in combination with laser and surgical treatment methods. In general, fixed drug combinations are preferred.

BB dosing regimen: 1–2 drops into the lower conjunctival sac of the affected eye(s) 2 times a day. The mechanism of action, side effects, and contraindications of BBs are presented in Table 5.

Table 5.

Characteristics of the BB pharmacological group

CAI dosing regimen: #brinzolamide 1% 1 drop into the lower conjunctival sac of the affected eye(s) 2 times a day. #dorzolamide 2% 1 drop into the lower conjunctival sac of the affected eye(s) 2–3 times a day [1–5]. The mechanism of action, side effects, and contraindications of carbonic anhydrase inhibitors are presented in Table 6.

Table 6.

Characteristics of the CAI pharmacological group

Dosing regimen for the glaucoma sympathomimetic #brimonidine 0.15%: 1 drop into the lower conjunctival sac of the affected eye(s) 3 times a day; brimonidine 0.2%: 1 drop 2 times a day [1–5].

The mechanism of action, side effects, and contraindications of brimonidine are presented in Table 7

Table 7.

Characteristics of the sympathomimetic pharmacological group for glaucoma treatment

The dosing regimen for PGAs is 1 drop into the lower conjunctival sac of the affected eye(s) once daily, preferably in the evening [1,3-5]. The mechanism of action, side effects, and contraindications of PGAs are presented in Table 8.

Table 8.

Characteristics of the PGA pharmacological group.

In patients with advanced primary open-angle glaucoma (POAG) and/or initially very high IOP levels, a more rapid transition to combination therapy is possible [1-4]. It is advisable to combine drugs with different mechanisms of action: those improving outflow and those reducing aqueous humor secretion. Fixed combinations are preferred to reduce problems such as decreased patient adherence due to instillation of multiple drops, reduced treatment efficacy due to washout of one drug by another, and increased preservative toxicity. Simultaneous administration of two fixed combinations is not recommended. Currently, almost all combinations available in Russia contain beta-blockers, which must be taken into account when prescribing them to patients with cardiopulmonary pathology [90-95].

Fixed drug combinations are generally preferable to two separate drugs [94, 95]. (Table 9)

Table 9.

Fixed combinations of antiglaucoma drugs and miotics

Comment: topical medications for primary angle-closure glaucoma are prescribed only when the potential benefit of treatment justifies the potential risk to the fetus. Basic principles of drug prescription: use the minimum number of drugs sufficient to achieve the target pressure, discuss treatment with an obstetrician-gynecologist and pediatrician, and reduce systemic absorption of the drug (by gentle pressure applied by the patient to the inner canthus or by using punctal occlusion). The most sensitive period is the first trimester of pregnancy due to the potential teratogenic effect on the fetus of systematically used antiglaucoma drugs and miotics. Considering the possible decrease in IOP during pregnancy in some patients, temporary discontinuation of topical hypotensive treatment under close monitoring may be considered. During pregnancy, beta-blockers may be prescribed, sympathomimetics for glaucoma treatment, and/or CAIs. Prostaglandin analogues should be used with caution due to their effect on uterine tone. Therefore, if signs of uterine hypertonus appear, their administration must be discontinued. At 9 months of pregnancy, beta-blockers and sympathomimetics for glaucoma treatment should be discontinued to avoid complications in the newborn. Topical CAIs may be continued. During lactation, it is preferable to prescribe topical CAIs and prostaglandin analogues. Laser iridotomy can be an initial or adjunctive intervention in pregnant and lactating women. In some cases, trabeculectomy without the use of antimetabolites may be considered [84, 97-99].

Comments. Acetazolamide** is a systemic CAI that reduces aqueous humor secretion by the ciliary body. Route of administration and dosage: orally 0.25 g 1–3 times a day. A single dose of #acetazolamide** may be reduced to 125 mg [179, 180]. A 2-day break is taken after every 5 days of administration. With prolonged use, other mineral supplements (potassium preparations) and a potassium-sparing diet are required.

Contraindications: hypersensitivity (including to other sulfonamides), hyponatremia, hypokalemia, adrenal insufficiency, renal and/or hepatic failure, liver cirrhosis (risk of encephalopathy), urolithiasis (with hypercalciuria), hyperchloremic acidosis, chronic decompensated angle-closure glaucoma (with long-term therapy), diabetes mellitus, uremia, breastfeeding. Adverse effects: paresthesia, skin pruritus, skin hyperemia, decreased appetite, vomiting, diarrhea, weight loss, hemolytic anemia, leukopenia, agranulocytosis, urinary disorders.

Comments. Solutions with osmodiuretic action (mannitol** 15%) increase blood osmotic pressure, which is accompanied by the flow of fluid from tissues into the blood, thereby reducing intracranial and intraocular pressure. By decreasing water reabsorption in the proximal tubules, these drugs exert a diuretic effect. IOP decreases on average within 30 minutes after administration of osmodiuretic solutions, with the maximum effect developing within 60 minutes and lasting for 4–6 hours. Dosage regimen: glycerol 50% solution – orally 1–2 g/kg body weight once daily; mannitol** 15% solution is administered intravenously by drip infusion for at least 30 minutes at 1.5–2 g/kg body weight during an acute glaucoma attack. Adverse effects: vomiting, nausea, diarrhea, dizziness, convulsions, hypotension or hypertension, tachycardia, urinary disorders, metabolic disturbances. Use with caution in patients with diabetes mellitus.

Comments. Medical treatment of an acute glaucoma attack includes the emergency use of beta-blockers, CAIs, glaucoma sympathomimetics, parasympathomimetics, osmoduretic solutions, glucocorticoids, nonsteroidal anti-inflammatory drugs, etc., taking into account contraindications for each individual patient. CAIs, beta-blockers, or glaucoma sympathomimetics may be used as first-line therapy either alone or in combination. Beta-blockers reduce IOP by approximately 20-30% within 1 hour after instillation; glaucoma sympathomimetics reduce IOP by approximately 26% within 2 hours after instillation [101-103].

In APACG, aqueous suppressant drugs may be ineffective in the presence of severe ciliary body ischemia. Parasympathomimetics may fail to constrict the pupil when IOP exceeds 40 mm Hg due to pupillary sphincter ischemia [104].

Intensive treatment with parasympathomimetics is no longer used for APACG due to systemic adverse effects (cramping abdominal pain and sweating) [1].

Laser iridotomy (LI) or surgical iridectomy, if the laser procedure is not available, should be performed as soon as possible in APACG. LI is possible once corneal edema resolves, which may take from a few hours to 1–2 days. The risk of complications from laser iridotomy is outweighed by the benefits of the procedure. Correct emergency treatment leads to the relief of the acute glaucoma attack in the majority of patients [4]. The set of measures recommended for the management of APACG is specified in Appendix B.

Comments: In the presence of pupillary block in PACG patients with axial hyperopia, microphthalmos, and AC, inducing cycloplegia with atropine** 1% drops (or injections of #atropine** 0.1%) causes paralysis of the ciliary muscle, expands the ring of ciliary processes, tightens zonular fibers, and moves the lens posteriorly. Phenylephrine 2.5% drops (or injections of #phenylephrine** 1%) are used to tighten the zonular fibers of the lens by stimulating the longitudinal muscles of the ciliary body [86, 105-107].

Atropine** 1% – an M-anticholinergic drug affecting both central and peripheral muscarinic receptors. It causes mydriasis, cycloplegia, and reduces lacrimal secretion. When applied topically in ophthalmology, maximum pupil dilation occurs in 30–40 minutes and resolves within 7–10 days. Atropine-induced mydriasis is not reversed by the instillation of parasympathomimetics. Dosage regimen: for topical use, instill 1–2 drops of the 1% solution 3 times a day. Adverse effects with topical use: hyperemia of the eyelid skin, hyperemia and edema of the palpebral and bulbar conjunctiva, photophobia, dry mouth, tachycardia. Contraindications: hypersensitivity to atropine. Use during pregnancy and lactation: atropine crosses the placental barrier. Intravenous administration during pregnancy or shortly before delivery may lead to fetal tachycardia. Use with caution in patients with cardiovascular diseases in which an increase in heart rate is undesirable; in intestinal atonia in elderly or debilitated patients (obstruction may develop); in prostatic hypertrophy and urinary retention. In some cases, 0.1% atropine** solution is administered subconjunctivally (0.2–0.5 ml) or parabulbar (0.3–0.5 ml). When atropine** is administered subconjunctivally or parabulbar, the patient should be given a validol tablet sublingually to reduce tachycardia. The sympathomimetic phenylephrine 2.5% contracts the pupillary dilator muscle, thereby causing mydriasis, as well as the smooth muscle of the conjunctival arterioles. Adverse effects with topical use: increased or decreased blood pressure, cardiac pain, palpitations, tachycardia, cardiac arrhythmias, reflex bradycardia, headache, dizziness, agitation, nausea or vomiting, respiratory depression, oliguria, acidosis, skin pallor, sweating. In some cases, 1% phenylephrine** solution is administered subconjunctivally in a dose of 0.2–0.5 ml.

3.2 Laser Treatment

Comments: LPI is the preferred treatment method for patients with suspected PAC, PAC, PACG, and acute PACG immediately after diagnosis [111]. It is a procedure that allows aqueous humor to flow directly from the posterior chamber into the anterior chamber through openings in the iris. LPI successfully eliminates the relative pupillary block component, regardless of whether the primary angle closure is primarily related to pupillary block or another mechanism [113].

Indications for LPI: prevention of acute PACG, achievement of target pressure, long-term IOP control, prevention of goniosynechiae formation, and prevention of further angle closure. 30 minutes before surgery, the patient undergoes instillation of a local anesthetic for ophthalmic use and 1% pilocarpine to reduce iris thickness and facilitate perforation [1]. Changes in angle configuration after LPI can be quantified using gonioscopy or imaging techniques (anterior segment optical coherence tomography / ultrasound biomicroscopy) [114]. In cases of residual angle closure after LPI, progressive synechia-induced angle closure may occur due to non-pupillary block mechanisms. The efficacy of LPI in patients with PACG depends on both the primary angle closure mechanism and the stage of the disease at the time of diagnosis. Up to 35% of PACG patients have a "closed angle" after LPI [38, 115, 116].

Comments: The administration of anti-glaucoma medications and miotics (parasympathomimetics, beta-blockers, carbonic anhydrase inhibitors, sympathomimetics for glaucoma treatment, prostaglandin analogs, solutions with osmodiuretic action) can reduce the severity of reactive hypertension following LI [118, 119].

Comments: Reactive hypertension is more pronounced in extensive synechial angle closure due to impaired outflow through the remaining open portion of the trabecular meshwork caused by iris particles and pigment debris following LI. Prior administration of 1% pilocarpine and instillation of 0.1%–0.15%–0.2% brimonidine, 1–2 drops (in the absence of contraindications in a specific patient) 1 hour and/or immediately before LI reduces the risk of iris hemorrhage and the severity of reactive hypertension [121].

The prescription of anti-inflammatory therapy (0.1% indomethacin, 1–2 drops 3 times a day, or 0.1% nepafenac, 1–2 drops 2 times a day, or 0.09% bromfenac, 1–2 drops once a day, or 0.1% dexamethasone, 1–2 drops 3 times a day, or 0.1% fluorometholone, 1–2 drops 3 times a day) for 4–7 days after LI reduces the likelihood of postoperative complications (reactive hypertension, post-coagulation uveitis, posterior synechiae).

The use of 0.1% dexamethasone may be a factor contributing to prolonged IOP elevation after LI. Postoperative complications are more characteristic of individuals with dark, thick irides (more common in the Asian population) [122, 123].

Posterior synechiae and irreversible miosis may develop after laser iridotomy as a result of prolonged administration of parasympathomimetics and/or inadequate anti-inflammatory therapy.

Comments: LGP allows widening the iridocorneal angle profile by contracting the peripheral part of the iris. Whenever possible, laser gonioplasty is recommended to be performed after laser iridotomy. The indication is chronic PACG developing over a long period, often against the background of pre-existing POAG with factors predisposing to angle closure (hyperopia, increased lens size). In "platelet iris" syndrome, LGP is sometimes considered an alternative to chronic parasympathomimetic administration.

Following LGP, pigmented iris burns develop at the coagulation sites. Since gonioplasty is often performed in patients with a shallow anterior chamber, diffuse corneal endothelial burns may occur. Pupil dislocation and persistent mydriasis are considered serious complications.

LGP is performed using a green or blue-green argon laser.. The patient is instilled with a topical ophthalmic anesthetic and 1% pilocarpine 30 minutes before the procedure [125].

Prescription of anti-inflammatory therapy (indometacin 0.1% 1–2 drops 3 times daily, or nepafenac 0.1% 1–2 drops 2 times daily, or bromfenac 0.09% 1–2 drops 1 time daily, or dexamethasone 0.1% 1–2 drops 3 times daily or fluorometholone 0.1% 1–2 drops 3 times daily) for 7–14 days after LGP reduces the likelihood of postoperative complications (reactive hypertension, post-coagulation uveitis, posterior synechiae).

Comments: Instillation of brimonidine 0.15–0.2% 1–2 drops (in the absence of contraindications for a specific patient) 1 hour and/or immediately before laser trabeculoplasty may reduce the severity of reactive hypertension [121, 128].

Prescription of anti-inflammatory therapy (indometacin 0.1% 1–2 drops 3 times daily, or nepafenac 0.1% 1–2 drops 2 times daily, or bromfenac 0.09% 1–2 drops 1 time daily, or dexamethasone 0.1% 1–2 drops 3 times daily or fluorometholone 0.1% 1–2 drops 3 times daily) for 4–7 days after laser trabeculoplasty reduces the likelihood of postoperative complications (reactive hypertension, post-coagulation uveitis, peripheral goniosynechiae) [1].

Comments: During the procedure, it is necessary to assess potential risks of complications, including postoperative inflammation, vision loss, hypotony, and subatrophy of the eyeball [132, 133].

3.3 Surgical Treatment

Comments: if angle closure progresses and/or the target pressure is not achieved in patients following LI, the following surgical interventions may be chosen: 1) trabeculectomy (sinustrabeculectomy), 2) lens extraction, 3) combined intervention – trabeculectomy (sinustrabeculectomy) / lens extraction.

Comments: trabeculectomy (sinustrabeculectomy) in PACG is effective; however, unlike primary open-angle glaucoma (POAG), there is a significant risk of complications, especially in anatomically predisposed eyes (short axial length, hyperopic refraction, shallow anterior chamber, deep-set eyes). In eyes that have recently undergone APACG, additional difficulties are posed by hyperemic conjunctiva, corneal edema, and a shallow anterior chamber. Furthermore, the risk of intraoperative expulsive hemorrhage and malignant glaucoma, as well as cataract progression, increases [135, 136].

Comments: intra- and postoperative correction of excessive scarring includes improvement of surgical stages (use of viscoelastics, adjustable sutures, etc.), administration of medications (antimetabolites – #fluorouracil and #mitomycin), implantation of antiglaucoma drains, revision (needling) of the filtration bleb, and sub-scleral needling. [137-141]. Antimetabolites are not officially registered as ophthalmic drugs; however, their use in fistulizing surgeries has entered clinical practice in many cases. The use of antimetabolites is considered potentially hazardous and requires meticulous surgical technique to prevent potential complications (hypotony, excessive thinning of the filtration bleb, risk of infection). In each case, it is important to evaluate the potential risks and the necessity of achieving a lower IOP when choosing a method to correct excessive scarring.

Comments: clinical studies confirm the positive outcomes of phacoemulsification with or without intraocular lens implantation in PACG, which include an increase in anterior chamber depth, widening of the iridocorneal angle, and an additional reduction in IOP [146-148]. However, clear indications for cataract surgery in the comprehensive management of PACG remain undefined, including the advisability of clear lens extraction as a primary treatment method instead of LI and/or medical therapy. Cataract surgery in PACG is generally more challenging and is associated with an increased risk of complications due to a shallow anterior chamber, large lens size, corneal edema, inadequate pupillary mydriasis, presence of posterior synechiae, lower endothelial cell count, and weak zonular fibers, especially following an acute attack.

Comments: lens extraction has a less pronounced hypotensive effect compared to when it is combined with trabeculectomy (sinustrabeculectomy). At the same time, combined surgery carries a higher risk of complications [152-154]. Potential risks and benefits must be evaluated on an individual basis in each case.

Comments: Laser procedures are preferred because they avoid potential surgical complications (shallow anterior chamber, formation of goniosynechiae, malignant glaucoma, endophthalmitis).

Comments: surgical treatment for MG should be performed in a timely manner to avoid irreversible changes in the anterior segment of the eye. Vitrectomy is performed not only to decompress the vitreous body, but also to establish a direct connection between the vitreous body and the anterior chamber [105, 156]. During vitrectomy, hyaloidotomy, capsulotomy, and iridectomy are performed at a single site, if necessary, to create a full connection between the anterior and posterior chambers. The effectiveness of the intervention is evaluated by an increase in anterior chamber depth and a reduction in IOP.

Comments: drainage surgery is recommended in the most complex cases. The choice of drainage device depends on technical capabilities and the surgeon's preference. Technically, the use of drainage devices in PACG is more complex than in POAG and carries a higher potential risk of serious complications. Their use is preferred in patients who have undergone prior filtering procedures without a sufficient hypotensive effect.

Comments: In modern anti-glaucoma surgery, laser transscleral cyclocoagulation is preferred. During these procedures, it is necessary to evaluate potential risks of complications such as postoperative inflammation, vision loss, hypotony, and subatrophy of the eyeball.

3.4 Diet therapy, pain management, and other treatments

There is no special diet for PACG.

Anesthesia methods are applied at the stage of laser and surgical treatment of PACG and during the management of an acute glaucoma attack.

Since the disease may progress in PACG patients despite an ostensibly adequate IOP level, the need for neuroprotective treatment in such patients is recognized. Alternative treatment strategies for glaucoma optic neuropathy (GON) are a subject of research and discussion [108]. According to multicenter studies (CNTGS, 1998; AGIS, 2000; EMGT, 2002; OHTS, 2002), guaranteeing long-term complete stabilization of the glaucomatous process is extremely difficult even with strict adherence to medical recommendations. The most promising among these has turned out to be neuroretinoprotection, designed to protect retinal neurons and optic nerve fibers from the damaging effects of various factors [159, 160, 162-165].

The role of individual representatives of the "Regenerants and reparants" group in neutralizing glutamate receptors—a retinal neurotransmitter whose excess triggers a cascade of irreversible biochemical and ionic reactions leading to accelerated death of retinal ganglion cells—has been proven [160, 166]. Meta-analysis and clinical study data confirm the neuroprotective effect of a water-soluble polypeptide fraction complex in patients with POAG [161, 165] and antioxidant drugs [167-168].

Comments: Drugs should be prescribed in courses, the frequency of which is determined by the attending physician. Conditions for prescription: chronic course of PACG and absence of contraindications to the drugs in the specific patient.

Prescription of neuroprotective therapy upon achievement of target IOP: S01XA other ophthalmological drugs (#cattle eye polypeptides parabulbar or intramuscularly 5 mg once daily) and/or N07XX other drugs for disorders of the nervous system (#ethylmethylhydroxypyridine succinate** intramuscularly 100-300 mg/day 1-3 times/day for 14 days) increases the probability of stabilization of glaucomatous optic neuropathy [163-167].

4. Medical Rehabilitation and Sanatorium-Resort Treatment

Medical rehabilitation is provided on a scheduled basis within the framework of primary health care and specialized, including high-tech, medical care.

Medical rehabilitation is carried out in the following settings:

• outpatient (in settings not providing round-the-clock medical monitoring and treatment);

• day hospital (in settings providing medical monitoring and treatment during daytime hours, but not requiring round-the-clock medical monitoring and treatment);

• inpatient (in settings providing round-the-clock medical observation and treatment).

5. Prevention and Dispensary Observation

Systematic reviews or studies providing data on the cost-effectiveness of screening to detect PACG, as well as POAG, are lacking, and published data are contradictory [3, 170-172].

Comments: The first stage of health screening (dispensarization) is carried out to identify signs of PACG and risk factors in citizens, especially with a burdened family history; and to determine medical indications for additional examinations and evaluations by an ophthalmologist to clarify the glaucoma diagnosis.

Comments: Immediate LI is necessary on the fellow eye after an episode of APACG if a narrow iridocorneal angle is present, since approximately half of the patients have a probability of developing APACG within 5 years [174-178].

Comments: in PACG patients receiving drug therapy, the efficacy and any adverse effects of treatment are assessed; changes and new prescriptions by other specialists for systemic indications that may affect glaucoma treatment are identified; and the patient's adherence to the hypotensive glaucoma therapy regimen is monitored. In patients after surgical interventions, the functional and hypotensive effects of surgery are evaluated, postoperative treatment (antimicrobial, anti-inflammatory, reparative, etc.) is adjusted, and other ophthalmic pathologies (cataract, uveitis, diabetic retinopathy, dry eye syndrome, etc.) are monitored and treated. In patients with a filtration bleb, its height, width, presence of thinning, vascularization, encapsulation, active filtration, and infection must be assessed.

Each patient visit is accompanied by an assessment of the patient's subjective well-being, visual functions (difficulties with driving, dark adaptation, contrast sensitivity problems, reading small print, and distance estimation), quality of life, and treatment adherence. Risk factors are reassessed at each patient visit.

In stabilized PACG with achieved target pressure, no progression of the iridocorneal angle status, optic disc, and visual fields, visometry and ophthalmotonometry should be performed at least once every 6 months, and computer perimetry, gonioscopy, and ophthalmoscopy once every 6-12 months. In unstabilized glaucoma, every 1-4 months depending on the severity grade and presence of risk factors.

When assessing a patient's quality of life, emphasis should be placed on improving the patient's condition. The use of quality-of-life questionnaires assessing disease burden and treatment burden may be utilized.

6. Organization of Medical Care

Main principles of organizing medical care during an acute glaucoma attack:

1) Diagnosis of acute angle-closure glaucoma at the prehospital stage.

2) Management of emergency therapeutic measures at the prehospital stage.

3) Early hospitalization if the acute angle-closure glaucoma attack is not relieved.

4) Diagnostic and emergency therapeutic measures, pathogenetic and symptomatic treatment at the hospital stage.

5) Measures for the prevention of an acute glaucoma attack in the fellow eye and follow-up dispensary observation.

Main principles of medical care organization for PACG:

Primary specialized health care is provided by an ophthalmologist in the outpatient department of a medical organization.

Treatment (laser interventions, medical conservative or physiotherapeutic treatment) is carried out in an outpatient setting, day care setting, or inpatient setting.

Indication for planned hospitalization in a medical organization:

- need for surgical treatment of PACG and/or laser treatment and/or medical treatment when outpatient or day care treatment is not feasible.

Indication for emergency hospitalization in a medical organization:

- unrelieved acute primary angle-closure glaucoma (APACG).

- endophthalmitis as a complication of acute glaucoma attack (AGA).

Indication for patient discharge from a medical organization:

1) completion of treatment or one of the stages of specialized, including high-tech, medical care in an inpatient or day care setting, provided there are no complications requiring drug correction and/or medical interventions in an inpatient setting;

2) refusal of the patient or their legal representative from specialized, including high-tech, medical care in an inpatient or day care setting, confirmed by a medical board of the medical organization;

3) need to transfer the patient to another medical organization.

7. Additional Information

The risk of disease progression to an advanced stage is higher in patients who do not adhere to the hypotensive eye drop instillation regimen.

Prospects for PACG treatment to preserve visual functions depend on the timely initiation of treatment and adherence to the optimal hypotensive therapy regimen in accordance with the drug instructions and clinical guidelines based on regular follow-up data.

Patients with early and moderate stages of glaucoma retain visual functions and have a moderately impaired quality of life, whereas advanced disease (due to the loss of visual functions) leads to a significant deterioration in quality of life. Therefore, early detection of the disease becomes most significant for preserving vision and preventing glaucoma blindness.

Criteria for Evaluating the Quality of Medical Care

Table 10.1 - Quality assessment criteria for primary health care provided to adults with primary angle-closure glaucoma (ICD-10 codes: H40.2)

Table 10.2 - Quality assessment criteria for specialized medical care provided to adults with primary angle-closure glaucoma (ICD-10 codes: H40.2)

References

Appendix A1. Working Group Composition

1. Antonov A.A., PhD in Medical Sciences, Leading Researcher, Glaucoma Department, FSBSI "M.M. Krasnov Research Institute of Eye Diseases", Association of Ophthalmologists, Moscow

2. Astakhov S.Yu., MD, Professor, Head of the Department of Ophthalmology, First Saint Petersburg State Pavlov Medical University, Association of Ophthalmologists, Saint Petersburg

3. Brezhnev A.Yu., PhD in Medical Sciences, Associate Professor, Kursk State Medical University of the Russian Ministry of Health, Ophthalmological Clinical Hospital – Ophthalmological Center, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Kursk

4. Brzheskiy V.V., MD, Professor, Head of the Department of Ophthalmology, Saint Petersburg State Pediatric Medical University of the Russian Ministry of Health, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Saint Petersburg

5. Gazizova I.R., MD, Institute of Experimental Medicine "Medical Research Center", Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Saint Petersburg

6. Golubev S.Yu., PhD in Medical Sciences, Senior Researcher, State Research Center of the Russian Federation – Institute of Biomedical Problems of the RAS, Association of Ophthalmologists, Moscow

7. Dogadova L.P., PhD in Medical Sciences, Professor of the Department of Ophthalmology, Pacific State Medical University of the Russian Ministry of Health, Chief Ophthalmologist of the Far Eastern Federal District, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Vladivostok

8. Egorov E.A., MD, Professor of the Academician A.P. Nesterov Department of Ophthalmology, Faculty of General Medicine, Pirogov Russian National Research Medical University of the Russian Ministry of Health, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Moscow

9. Erichev V.P., MD, Professor, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Moscow

10. Ivanova N.V., MD, Professor, Head of the Department of Eye Diseases, S.I. Georgievsky Medical Academy of Vernadsky Crimean Federal University, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Simferopol

11. Zhuravleva A.N., PhD in Medical Sciences, Researcher, Glaucoma Department, National Medical Research Center of Eye Diseases named after Helmholtz of the Russian Ministry of Health, Association of Ophthalmologists, Moscow

12. Zolotarev A.V., MD, Associate Professor, Head of the Department of Ophthalmology, Samara State Medical University of the Russian Ministry of Health, Chief Physician of the T.I. Eroshevsky Samara Regional Clinical Ophthalmological Hospital, Association of Ophthalmologists, Samara

13. Karlova E.V., MD, Assistant Professor of the Department of Ophthalmology, Samara State Medical University of the Russian Ministry of Health, Head of the Ophthalmological Department, T.I. Eroshevsky Samara Regional Clinical Ophthalmological Hospital, Association of Ophthalmologists, Samara

14. Kosakyan S.M., PhD in Medical Sciences, Ophthalmologist, Glaucoma Department, National Medical Research Center of Eye Diseases named after Helmholtz of the Russian Ministry of Health, Association of Ophthalmologists, Moscow

15. Konovalova O.S., PhD in Medical Sciences, Head of the Tyumen Branch of the Ekaterinburg Eye Microsurgery MDC JSC, Associate Professor of the Department of Surgical Diseases with a Course in Ophthalmology, Tyumen State Medical University, Association of Ophthalmologists, Tyumen

16. Kulikov A.N., MD, Professor, Head of the Prof. V.V. Volkov Department and Clinic of Ophthalmology, Kirov Military Medical Academy of the Ministry of Defense of the Russian Federation, Chief Ophthalmologist of the Ministry of Defense of the Russian Federation, Chief freelance ophthalmologist of Saint Petersburg, Russian Glaucoma Society, The Society of Ophthalmologists of Russia, Saint Petersburg

17. Kuroedov A.V., MD, DSc, Head of the Ophthalmological Center, Mandryk Central Military Clinical Hospital of the Ministry of Defense of the Russian Federation, Head of the Department of Ophthalmology named after Academician A.P. Nesterov, Faculty of General Medicine, Pirogov Russian National Research Medical University of the Ministry of Health of the Russian Federation, Russian Glaucoma Society, Russian Ophthalmological Society, Moscow

18. Lebedev O.I., MD, DSc, Professor, Head of the Department of Ophthalmology, Omsk State Medical University of the Russian Ministry of Health, Association of Ophthalmologists, Omsk

19. Lovpache J.N., Cand. Sc. (Med.), Independent Expert, 3Z-MSK Eye Clinic, Russian Glaucoma Society, Russian Ophthalmological Society, Moscow

20. Malishevskaya T.N., MD, DSc, Head of the Analytical Work Department, Helmholtz National Medical Research Center of Eye Diseases of the Ministry of Health of the Russian Federation, Associate Professor at the Department of Continuing Medical Education, Helmholtz National Medical Research Center of Eye Diseases of the Ministry of Health of the Russian Federation, Association of Ophthalmologists, Moscow

21. Malyugin B.E., MD, DSc, Corresponding Member of the RAS, Professor, Deputy General Director for Research, S. Fyodorov Eye Microsurgery Federal State Institution, Russian Ophthalmological Society, Moscow

22. Nikolaenko V.P., MD, DSc, Professor at the Department of Otorhinolaryngology and Ophthalmology, Saint Petersburg State University, Deputy Chief Medical Officer for Ophthalmology, City Multidisciplinary Hospital No. 2, Association of Ophthalmologists, Russian Glaucoma Society, Saint Petersburg

23. Onufriychuk O.N., Cand. Sc. (Med.), Ophthalmologist, Turner National Medical Research Center for Children's Orthopedics and Trauma of the Ministry of Health of the Russian Federation, Pirogov Clinic of High Medical Technologies of Saint Petersburg State University, Russian Glaucoma Society, Russian Ophthalmological Society, Saint Petersburg

24. Petrov S.Yu., MD, DSc, Head of the Glaucoma Department, Helmholtz National Medical Research Center of Eye Diseases of the Ministry of Health of the Russian Federation, Professor at the Department of Continuing Medical Education, Helmholtz National Medical Research Center of Eye Diseases of the Russian Ministry of Health, Association of Ophthalmologists, Moscow

25. Ryabtseva A.A., MD, DSc, Professor, Ophthalmologist at the Treatment and Rehabilitation Center of the Ministry of Foreign Affairs of Russia, Chief Freelance Ophthalmologist of the Central Federal District, Professor at the Department of Eye Diseases, Semashko National Research Institute of Public Health, Association of Ophthalmologists, Moscow

26. Seleznev A.V., Cand. Sc. (Med.), Associate Professor, Ivanovo State Medical Academy of the Ministry of Health of the Russian Federation, Russian Glaucoma Society, Russian Ophthalmological Society, Ivanovo

27. Simonova S.V., Cand. Sc. (Med.), City Clinical Hospital No. 15 named after O.M. Filatova of the Moscow Healthcare Department, Russian Glaucoma Society, Moscow

28. Sokolovskaya T.V., Cand. Sc. (Med.), Leading Researcher at the Department of Surgical Glaucoma Treatment, S. Fyodorov Eye Microsurgery Federal State Institution, Russian Ophthalmological Society, Moscow

29. Fursova A.Zh., MD, DSc, Honored Doctor of the Russian Federation, Head of the Ophthalmological Department, State Novosibirsk Regional Clinical Hospital, Association of Ophthalmologists, Novosibirsk

30. Yuryeva T.N., MD, DSc, Professor, Deputy Director for Research, Irkutsk Branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Association of Ophthalmologists, Irkutsk

31. Yakubova L.V., Cand. Sc. (Med.), Senior Researcher at the Glaucoma Department, Helmholtz National Medical Research Center of Eye Diseases of the Ministry of Health of the Russian Federation, Association of Ophthalmologists, Moscow

No conflict of interest.

Appendix A2. Methodology for Developing Clinical Guidelines

Methods used for evidence collection/selection: electronic database search, library resources. Description of methods used for evidence collection/selection: the evidence base for the guidelines includes publications from the Cochrane Library, EMBASE, and MEDLINE databases, as well as monographs and articles in leading specialized peer-reviewed domestic medical journals on the subject. The search depth was 10 years. Methods used to assess the quality and strength of evidence: expert consensus, significance assessment in accordance with the rating scheme.

Target audience for these clinical guidelines:

1. Ophthalmologists

2. Medical students

Table 1. Levels of Evidence (LoE) grading scale for diagnostic methods (diagnostic interventions)

Table 2. Scale for grading levels of evidence certainty (LEC) for prevention, treatment, and rehabilitation methods (preventive, therapeutic, and rehabilitative interventions)

Table 3. Scale for grading grades of recommendation (GR) for prevention, diagnostic, treatment, and rehabilitation methods (preventive, diagnostic, therapeutic, and rehabilitative interventions)

Procedure for updating clinical guidelines.

The mechanism for updating clinical guidelines provides for their systematic revision at least once every three years, as well as upon the emergence of new evidence-based medicine data on the diagnosis, treatment, prevention, and rehabilitation of specific diseases, or in the presence of justified additions/comments to previously approved clinical guidelines, but no more frequently than once every 6 months.

Appendix A3. Reference Materials

These clinical guidelines were developed taking into account the following documents:

1. International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) (World Health Organization) 1994.

2. Order of the Russian Ministry of Health No. 804n dated October 13, 2017 (as amended on September 24, 2020, with amendments dated October 26, 2022) "On Approval of the Nomenclature of Medical Services" (Registered with the Ministry of Justice of Russia on November 7, 2017, No. 48808)

3. Federal Law No. 323-FZ "On the Fundamentals of Protecting the Health of Citizens in the Russian Federation" dated November 21, 2011.

4. Order of the Russian Ministry of Health No. 114n dated February 25, 2022 "On Approval of the Standard of Medical Care for Adults with Primary Open-Angle Glaucoma (Diagnosis, Treatment, and Dispensary Observation)" (Registered with the Ministry of Justice of Russia on April 4, 2022, No. 68043)

5. Order of the Russian Ministry of Health No. 116n dated February 25, 2022 "On Approval of the Standard of Medical Care for Adults with Primary Angle-Closure Glaucoma (Diagnosis, Treatment, and Dispensary Observation)" (Registered with the Ministry of Justice of Russia on April 4, 2022, No. 68044)

6. Order of the Russian Ministry of Health No. 902n dated November 12, 2012 "On Approval of the Procedure for Providing Medical Care to the Adult Population for Diseases of the Eye, Its Adnexa, and Orbit."

7. Decree of the Government of the Russian Federation No. 2406-r dated October 12, 2019 (as amended on April 16, 2024) <On Approval of the List of Vital and Essential Medicines, as well as Lists of Medicines for Medical Use and the Minimum Assortment of Medicines Required for Medical Care>

8. Order of the Russian Ministry of Health No. 103n dated February 28, 2019 "On Approval of the Procedure and Deadlines for the Development of Clinical Guidelines, Their Revision, the Standard Form of Clinical Guidelines, and Requirements for Their Structure, Composition, and Scientific Validity of Information Included in Clinical Guidelines."

9. "On the Program of State Guarantees of Free Medical Care to Citizens for 2024 and for the Planning Period of 2025 and 2026." Decree of the Government of the Russian Federation No. 2353 dated December 28, 2023.

10. "On Approval of the Procedure for Conducting Dispensary Observation of Adults." Order of the Ministry of Health of the Russian Federation No. 168n dated March 15, 2022.

11. "On the List of Diseases or Conditions (Groups of Diseases or Conditions) in Which the Use of a Medicinal Product is Permitted in Accordance with Indicators (Characteristics) of the Medicinal Product Not Specified in Its Instructions for Use." Decree of the Government of the Russian Federation No. 1180-r dated May 16, 2022.

12. "On Approval of the Procedure for Conducting Preventive Medical Examinations and Medical Check-ups (Dispensary Profiling) of Certain Groups of the Adult Population" (as amended by Order of the Russian Ministry of Health No. 44n dated February 1, 2022). Order of the Ministry of Health of the Russian Federation No. 404น dated April 27, 2021.

13. "On Approval of Lists of Medical Indications and Contraindications for Sanatorium-Resort Treatment" Order of the Russian Ministry of Health No. 1029n dated September 28, 2020 (as amended on April 26, 2023).

14. "On Approval of the Standard of Sanatorium-Resort Care for Patients with Diseases of the Eye and Its Adnexa." Order of the Ministry of Health and Social Development of the Russian Federation No. 215 dated November 22, 2004.

15. "On Approval of the Standard of Medical Care for Adults with Suspected Glaucoma (Diagnosis, Treatment, and Dispensary Observation)." Order of the Ministry of Health of the Russian Federation No. 115n dated February 25, 2022.

16. "On Approval of Accounting Form of Medical Documentation No. 131/u 'Card for Accounting of Preventive Medical Examination (Dispensary Profiling)', the Procedure for Its Maintenance and the Form of Industry Statistical Reporting No. 131/o 'Information on Conducting Preventive Medical Examinations and Dispensary Profiling of Certain Groups of the Adult Population', the Procedure for Its Completion and Submission Deadlines." Order of the Ministry of Health of the Russian Federation No. 1207n dated November 10, 2020.

17. "On Approval of Lists of Medical Indications and Contraindications for Sanatorium-Resort Treatment." Order of the Ministry of Health of the Russian Federation No. 1029n dated September 28, 2020 (as amended by Orders of the Russian Ministry of Health No. 664n dated October 13, 2022, No. 193n dated April 26, 2023).

Appendix B. Physician Action Algorithms

Interventions recommended for the treatment of an acute attack of angle-closure glaucoma

1. Place the patient in a horizontal position.

2. Instill into the affected eye once: brimonidine 0.15% or 0.2% 1 drop, timolol 0.5% or betaxolol 0.5% 1 drop, dorzolamide 2% or brinzolamide 1% 1 drop (in the absence of systemic contraindications to their prescription).

3. Administer acetazolamide 250-500 mg orally (use with caution in patients with urolithiasis).

4. Instill dexamethasone 0.1% 1-2 drops into the affected eye three times at 5-minute intervals.

5. If the IOP is below 40 mmHg, instill pilocarpine 1% 1-2 drops into the affected eye 2-3 times over the course of an hour.

6. Instill pilocarpine 1% or 2% 1-2 drops once in the contralateral eye.

7. Therapeutic corneal compression with a 4-mirror gonioscope for 20 seconds.

8. If there is no tendency for the acute attack to resolve, administer mannitol 15% solution intravenously by drip infusion over at least 30 minutes at 1.5-2 g/kg of body weight.

9. Analgesics and/or antipyretics and antiemetics in the presence of pain and nausea (every 4 hours).

10. Laser iridectomy after resolution of the acute attack and corneal edema.

11. Gonioscopy with compression to assess the extent of angle closure in order to determine further management tactics.

Appendix C. Patient Information

Glaucoma is a chronic disease in which individuals over the age of 40-50 develop optic nerve atrophy, which, upon progression, leads to irreversible visual impairment, and in severe cases, to total blindness. As a rule, the disease develops in both eyes, but may manifest in the second eye months or years later. In the vast majority of cases, vision decreases due to elevated intraocular pressure exceeding the individual target level.

In the early stages of glaucoma, there are no symptoms whatsoever; a patient may only discover vision loss or localized visual field defects when the condition is advanced, at which point curing glaucomatous optic atrophy and restoring lost functions is impossible.

Therefore, early detection of glaucoma is only possible during a routine annual check-up (dispensary examination) with an ophthalmologist or when seeking medical attention due to deteriorating vision.

The symptoms are characteristic of an acute attack of angle-closure glaucoma, which involves a sudden, rapid, and uncontrolled spike in intraocular pressure accompanied by eye pain radiating to the corresponding half of the head (forehead, temple); nausea, vomiting, palpitations, elevated blood pressure, decreased visual acuity, and halos around light sources may also occur.

An acute attack of angle-closure glaucoma is a medical emergency and requires immediate medical attention!

Without treatment, an acute attack of angle-closure glaucoma can result in blindness!

The main goal of glaucoma treatment is to lower intraocular pressure, which helps stabilize the process or slow its progression. This can be achieved through daily, long-term (lifelong) eye drop instillation, as well as laser and/or surgical treatment. Indications for a particular treatment method are determined by the physician. A glaucoma patient requires regular follow-up by an ophthalmologist with intraocular pressure measurements at least once every 3 months.

With early detection of glaucoma and adequate treatment, the prognosis is favorable, preserving visual functions. In the absence of proper medical supervision and failure to follow treatment recommendations, glaucoma threatens complete blindness in both eyes.

Appendix G. Assessment Scales, Questionnaires, and Other Evaluation Tools

Appendix G1. Glaucoma Risk Calculator

Russian title: Glaucoma Risk Calculator for Individuals with Ocular Hypertension

Original title (if applicable): S.T.A.R II (The Scoring Tool for Assessing Risk) Glaucoma Risk Calculator

Source (official developer website, validation publication): Medeiros F.A., Weinreb R.N., Sample P.A. et al. Validation of a predictive model to estimate the risk of conversion from ocular hypertension to glaucoma. Arch Ophthalmol. 2005;123:1351-1360.

Type (underline): disease risk calculator

Purpose: determining the 5-year risk of developing glaucoma in patients with ocular hypertension

Content (template): parameters used: age, IOP level, CCT, vertical cup-to-disc ratio, visual field PSD index.

Key (interpretation): Based on the results obtained, the 5-year risk of developing glaucoma is estimated as:

A) Low (result below 5%). Recommended strategy: observation without treatment.

B) Moderate (result between 5-15%). Recommended strategy: decision on medical treatment is made individually, taking into account the patient's preference.

C) High (result above 15%). Recommended strategy: treatment aimed at lowering IOP.

Notes. An electronic version of the calculator is available for download on smartphones and tablets (http://www.pocket.md/80/star-ii.html). Currently, this is the most widely used glaucoma risk calculator for patients with ocular hypertension (Ameen S., Javaid F., Cordeiro M.F. Risk calculators in glaucoma // Exp Rev Ophthalmol. 2016; 11(1): 21-27. DOI: 10.1586/17469899.2016.1136213).

Appendix G2. Quality of life in glaucoma patients.

Russian title: The Glaucoma Quality of Life – 15 (GQL-15) Questionnaire

Original title (if applicable): The Glaucoma Quality of Life – 15 (GQL-15) questionnaire

Source (official developer website, validation publication): Nelson P., Aspinall P., Papasouliotis O., Worton B., O'Brien C. Quality of life in glaucoma and its relationship with visual function // J Glaucoma. 2003; 12(2): 139-150.

Type (underline): questionnaire

Purpose: assessment of quality of life in glaucoma patients

Content (template):

Patient instructions:

Please indicate the correct answer on a scale from 1 to 5, where [1] means "no difficulty", [2] – "slight difficulty", [3] – "moderate difficulty", [4] – "great difficulty", and [5] – "severe difficulty". If you do not perform certain activities for other reasons unrelated to your vision, please select answer [0].

Does your vision condition cause difficulty when performing the following activities?

Key (interpretation): The GQL-15 questionnaire consists of 15 items evaluating 4 main visual quality characteristics: (1) central and near vision; (2) peripheral vision; (3) dark adaptation; (4) out-of-home mobility. The total score characterizes the quality of life of a glaucoma patient. The higher the score, the lower the quality of life.

Notes. Currently, a significant number of questionnaires dedicated to studying the quality of life of glaucoma patients have been developed and are available (Glau-QoL, NEI-VFQ, TSS-IOP, and others). Varying degrees of validation and complexity for patients determine the nuances of their use in clinical practice. The presented questionnaire is user-friendly due to its conciseness and has received positive feedback from ophthalmologists and patients.

Appendix G3. Disk Damage Likelihood Scale (DDLS) for assessing and sketching optic disc changes during glaucoma patient follow-up

Russian title: Disk Damage Likelihood Scale for assessing and sketching optic disc changes in glaucoma patients

Original title (if available): DDLS, Disk Damage Likelihood Scale

Source (official developer website, validation study): Spaeth G.L., Henderer J., Liu C. et al. The disc damage likelihood scale: reproducibility of a new method of estimating the amount of optic nerve damage caused by glaucoma. Trans Am Ophthalmol Soc. 2002;100:181-5; Cheng K., Tatham A.J. Spotlight on the Disc-Damage Likelihood Scale (DDLS). Clin Ophthalmol. 2021;15:4059-4071.

Type (underline): rating scale

Purpose: assessment of optic disc changes in the monitoring of glaucoma patients

Content (template): parameters used: optic disc size, neuroretinal rim (NRR) to optic disc size ratio

Key (interpretation): first, the size of the optic disc is determined (using a slit lamp scale with special conversion factors: for a +60 D lens magnification, the obtained result is multiplied by 0.88; for a +78 D lens, by 1.2; for a +90 D lens magnification, by 1.63), then the size and configuration of the neuroretinal rim are determined.

Optic discs corresponding to stage 4 and above on the DDLS scale are considered pathological.

Notes. Clinical examination of the optic disc remains an essential component of glaucoma diagnosis and monitoring. The DDLS provides a reliable method for clinical grading of glaucomatous optic disc changes, with a higher degree of reproducibility compared to the classic cup-to-disc ratio measurement.