A 62-year-old man from Mumbai with a history of hyperopia and thick lens presents with intermittent episodes of blurred vision and mild eye discomfort over the past 2 weeks. On examination, the anterior chamber is shallow, and gonioscopy shows appositional angle closure in the superior and temporal quadrants without any synechiae. Intraocular pressure is 22 mmHg in both eyes. Anterior segment OCT confirms narrow angles bilaterally. What is the most appropriate next step in management?

Explanation

## Intermittent Angle Closure (Subacute/Chronic Angle Closure): Prophylactic Laser Iridotomy **Key Point:** A patient with appositional angle closure on gonioscopy (even without synechiae) and anatomical risk factors (hyperopia, shallow chamber, thick lens) is at HIGH RISK for acute angle-closure attacks. Prophylactic YAG laser peripheral iridotomy on BOTH eyes is indicated to prevent future acute episodes. ### Classification of Angle-Closure Spectrum | Stage | Clinical Features | Gonioscopy Findings | IOP | Management | |-------|------------------|-------------------|-----|-------------| | **Anatomically Narrow Angles (Risk)** | Asymptomatic | Appositional closure, no synechiae | Normal | Prophylactic iridotomy on both eyes | | **Intermittent/Subacute Closure** | Intermittent blurred vision, mild discomfort, halos | Appositional closure ± few synechiae | Normal to mildly elevated | Prophylactic iridotomy on both eyes | | **Acute Angle Closure** | Severe pain, blurred vision, nausea, vomiting | Appositional ± extensive synechiae | >40 mmHg | Medical therapy → Laser iridotomy | | **Chronic Angle Closure** | Often asymptomatic | Extensive synechiae, PAS | Elevated | Laser iridotomy + medical therapy | ### Why Prophylactic Iridotomy in This Case? 1. **Appositional angle closure is present** — the iris is in contact with the trabecular meshwork, blocking aqueous outflow 2. **Anatomical risk factors** — hyperopia, shallow anterior chamber, thick lens all predispose to angle closure 3. **Intermittent symptoms** — blurred vision and discomfort suggest transient episodes of angle narrowing, indicating the patient is at imminent risk of acute attack 4. **No synechiae yet** — this is the ideal time to intervene before permanent adhesions form (which would reduce the effectiveness of iridotomy) 5. **Bilateral involvement** — both eyes are at risk and both require prophylactic treatment ### Mechanism of YAG Laser Peripheral Iridotomy - Creates a full-thickness opening in the peripheral iris - Eliminates pupillary block by allowing direct communication between posterior and anterior chambers - Allows aqueous to flow from posterior chamber to anterior chamber without being blocked by the lens-iris diaphragm - Deepens the anterior chamber and opens the angle **High-Yield:** Prophylactic iridotomy is indicated in: - Anatomically narrow angles with appositional closure on gonioscopy - Intermittent angle-closure episodes - Fellow eye of acute angle-closure glaucoma - Narrow angles discovered incidentally in high-risk patients (hyperopia, short axial length, thick lens) **Mnemonic: NARROW angles require prophylactic iridotomy:** - **N**arrow anterior chamber on slit lamp - **A**ppositional closure on gonioscopy - **R**isk factors present (hyperopia, thick lens) - **R**ecurrent symptoms (blurred vision, halos) - **O**pportunity to prevent acute attack - **W**ider angle after iridotomy ### Timing - **Acute angle closure** → Medical therapy first, then urgent laser (within hours) - **Intermittent/subacute closure** → Prophylactic laser within 1–2 weeks (elective, not emergency) - **Anatomically narrow angles** → Prophylactic laser at convenience (can be deferred slightly but should not be delayed indefinitely) ### Post-Iridotomy Management - Confirm angle opening on gonioscopy 1–2 weeks after iridotomy - Continue IOP-lowering therapy if needed - Educate on avoiding mydriatic medications - Regular follow-up to monitor for any residual angle closure or synechiae formation