## Clinical Diagnosis and Management of Primary Open-Angle Glaucoma ### Key Clinical Features Present **High-Yield:** This patient demonstrates the classic diagnostic triad of primary open-angle glaucoma (POAG): 1. **Elevated IOP** — 28 mmHg (right) and 26 mmHg (left), both above the normal threshold of 21 mmHg 2. **Structural optic nerve damage** — Cup-to-disc ratio of 0.7 with superior and inferior notching (focal RNFL loss) 3. **Corresponding functional visual field defect** — Superior arcuate scotoma matching inferotemporal disc notching **Key Point:** When all three elements of the POAG triad are present on a single examination, the diagnosis is established and treatment should be initiated promptly. Delaying therapy risks further irreversible retinal ganglion cell loss and progressive visual field deterioration. ### Why Start Treatment Now? Per established guidelines (European Glaucoma Society, American Academy of Ophthalmology Preferred Practice Pattern), treatment is indicated when: - IOP is elevated AND - There is documented glaucomatous optic neuropathy (disc notching, increased C:D ratio) AND - A corresponding visual field defect is present This patient fulfills all three criteria. The visual field defect is not an isolated finding — it is spatially correlated with the structural disc changes (inferotemporal notching → superior arcuate defect), making artifact or false-positive highly unlikely. Repeating the VF is appropriate for *monitoring progression* but should not delay initiation of IOP-lowering therapy when the diagnosis is clinically evident. ### First-Line Medical Therapy | Agent Class | Examples | IOP Reduction | Mechanism | |---|---|---|---| | **Prostaglandin analogues** | **Latanoprost, travoprost, bimatoprost** | **25–35%** | ↑ Uveoscleral outflow | | Beta-blockers | Timolol | 20–25% | ↓ Aqueous production | | Carbonic anhydrase inhibitors | Dorzolamide | 15–20% | ↓ Aqueous production | | Alpha-2 agonists | Brimonidine | 20–25% | ↓ Production + ↑ uveoscleral outflow | **Clinical Pearl:** Prostaglandin analogues (e.g., latanoprost 0.005% once nightly) are the preferred first-line monotherapy for POAG per KD Tripathi and Khurana because they offer the greatest IOP reduction (25–35%), once-daily dosing, and minimal systemic side effects. Treatment is initiated in both eyes given bilateral IOP elevation and bilateral open angles. ### Why Not the Other Options? - **Option C (Repeat VF + OCT before treatment):** Appropriate for *borderline* or *suspected* glaucoma where the diagnosis is uncertain. In this patient, the triad is complete and spatially consistent — repeating tests before treating introduces unnecessary delay and risk of further irreversible damage. OCT and repeat VF are valuable for establishing a *baseline for monitoring*, but should be done alongside, not instead of, initiating therapy. - **Option B (Immediate laser trabeculoplasty):** Selective laser trabeculoplasty (SLT) is an acceptable first-line alternative in some guidelines, but topical medical therapy remains the conventional first step in most Indian and international practice guidelines. Laser is not the *most appropriate next step* when medical therapy is available. - **Option D (Observe without treatment):** Absolutely contraindicated. The patient has documented glaucomatous optic neuropathy with a corresponding VF defect. Observation risks progressive, irreversible vision loss. **Mnemonic: POAG Triad = IOP ↑ + Disc damage + VF defect → TREAT immediately with prostaglandin analogue** [cite: Khurana 6e Ch 10; KD Tripathi Essentials of Medical Pharmacology 8e; AAO PPP Glaucoma 2020]
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