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Primary open-angle glaucoma (POAG)
Primary open-angle glaucoma is a chronic progressive optic neuropathy — cupping of the optic disc with loss of nerve fibres and a matching visual field defect, with an open angle on gonioscopy — and the only factor that can be modified is intraocular pressure (IOP).
Why it matters in the exam
In the exam the question is built around three findings together: the disc (large cup-to-disc ratio, rim thinning that breaks the ISNT rule, a notch, a disc-margin haemorrhage), OCT of the retinal nerve fibre layer (RNFL) and the visual field (arcuate defect, nasal step and paracentral defects). Normal pressure is roughly 10–21 mmHg, but high pressure alone is not disease (ocular hypertension) and glaucoma can occur at normal pressure (normal tension glaucoma).
The risk factors asked about: age, raised pressure, African ancestry, family history, a thin cornea (low CCT — the measured pressure underestimates the true one), myopia and diabetes in some studies. The trials examiners like: OHTS — treating ocular hypertension lowered conversion to glaucoma from 9.5% to 4.4% at 5 years; EMGT — each 1 mmHg of reduction lowered the risk of progression by about 10%; CNTGS — in normal tension glaucoma a 30% reduction slowed progression.
Treatment starts with a target pressure — usually a 20–30% reduction from baseline — with a prostaglandin analogue or SLT laser as first line (the LiGHT trial showed primary SLT to be equivalent to drops). When disease progresses despite maximal therapy the next step is surgery: trabeculectomy with mitomycin C, a glaucoma drainage device (tube) or minimally invasive glaucoma surgery (MIGS) in mild to moderate disease.
Key points
- Optic neuropathy with a matching field defect and an open angle.
- IOP is the only modifiable factor.
- Initial target: a 20–30% reduction.
- First line: prostaglandin analogue or SLT.
- Progression despite treatment → trabeculectomy or tube.
Summary table
| Stage | Typical finding | What to do |
|---|---|---|
| Suspect / ocular hypertension | IOP above 21 mmHg, normal disc and field | Risk assessment (age, CCT, disc); treat when risk is high |
| Early glaucoma | RNFL thinning on OCT, disc notch or haemorrhage | Target reduction 20–30%; prostaglandin or SLT |
| Moderate glaucoma | Arcuate defect or nasal step on the field | Add a drug from another class; close field follow-up |
| Advanced glaucoma | Defect in both hemifields, fixation threatened | Lower target; surgery (trabeculectomy, tube) |
| Normal tension glaucoma | Typical damage with normal IOP | Exclude compressive and vascular causes; 30% reduction |
Free exam questions
גלאוקומה גברת בת 70 , ללא היסטוריה עינית מגיעה למיון בשל עין אדומה וכואבת .בבדיקה לישכה רדודה ,בגוניוסקופה זוית סגורה . לחץ 50 . בבדיקת העין השניה לישכה עמוקה וזוית פתוחה . איזה מבין המנגנונים הוא הסביר ביותר לסגירת הזוית? (the question as examined, in Hebrew)
- א. שימוש בתרופה טופירמט
- ב. גלאוקומה סגורת זוית ראשונית
- ג. פאקומורפיק גלאוקומה
- ד. ICE syndrome
מה מהבאים מאפיין Normal tension glaucoma ? (the question as examined, in Hebrew)
- א. המחלה גורמת בדרך כלל לפגם מפושט והיקפי בשדה הראייה
- ב. המחלה נפוצה יותר בנוכחות דום נשימה בשינה apnea Sleep
- ג. חשוב להוריד את הלחץ התוך עיני בלפחות 20%
- ד. המחלה נוטה להתקדם מהר יחסית
In the full version for subscribers
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Sources
- AAO Preferred Practice Pattern: Primary Open-Angle Glaucoma, 2020 — Diagnosis and management
- European Glaucoma Society: Terminology and Guidelines for Glaucoma, 5th edition (2020) — Primary open-angle glaucoma and treatment principles
- AAO Basic and Clinical Science Course, Section 10: Glaucoma, 2024-2025 — Open-angle glaucoma
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.