## Clinical Scenario: Progressive POAG Despite Monotherapy ### Evidence of Glaucomatous Progression | Parameter | Finding | Interpretation | |-----------|---------|----------------| | IOP on monotherapy | 18 mmHg (target 15 mmHg) | Above target; inadequate control | | Optic disc changes | Progressive rim thinning (2-year comparison) | Structural progression | | Visual field | New superior nasal step defect | Functional progression (new defect) | | Visual acuity | 6/6 bilaterally | Preserved; not advanced stage | | Compliance | Good (3-year monotherapy) | Adherence not the issue | **Key Point:** Progressive glaucomatous damage (both structural on disc and functional on VF) despite IOP at 18 mmHg indicates **inadequate IOP control relative to this patient's target**. The target IOP of 15 mmHg was not achieved, and the patient is demonstrating continued deterioration. ### Management of Progressive POAG on Monotherapy ```mermaid flowchart TD A[POAG on monotherapy with progressive damage]:::outcome A --> B{Is IOP at target?}:::decision B -->|No, above target| C[Intensify medical therapy]:::action B -->|Yes, at target but progressing| D[Lower target IOP further]:::action C --> E[Add second topical agent]:::action E --> F[Beta-blocker, alpha-2 agonist, or CAI]:::action F --> G[Recheck IOP in 4 weeks]:::action G --> H{IOP at new target?}:::decision H -->|Yes| I[Continue combination; monitor VF 6-monthly]:::outcome H -->|No| J[Add third agent or consider laser/surgery]:::action D --> K[Consider SLT or trabeculectomy]:::action ``` **High-Yield:** The presence of **progressive structural AND functional glaucomatous damage** while IOP is above the individualized target IOP mandates **escalation of medical therapy** before considering surgery. Adding a second topical agent is the standard next step in the treatment ladder. **Clinical Pearl:** Target IOP in glaucoma is individualized based on baseline IOP, severity of damage, and rate of progression. This patient's target of 15 mmHg was set because she had documented glaucomatous damage. Current IOP of 18 mmHg is insufficient to halt progression — a lower target is needed. **Mnemonic: Second-Line Topical Agents for POAG — "BACA"** - **B**eta-blockers (timolol, betaxolol) - **A**lpha-2 agonists (brimonidine, apraclonidine) - **C**arbonic anhydrase inhibitors (dorzolamide, brinzolamide — topical) - **A**dditional prostaglandin (if not already on one) ### Why NOT the Other Options? **Continue monotherapy with 6-month VF repeat (option A):** This patient has **documented progressive damage** (new VF defect, progressive disc changes) and IOP above target. Continuing the same therapy without escalation would allow further irreversible axonal loss. Waiting 6 months is inappropriate when progression is already evident. **Switch to a different prostaglandin analogue (option C):** All prostaglandin analogues (latanoprost, travoprost, bimatoprost) have similar efficacy (25–35% IOP reduction). Switching within the same drug class without adding a second agent is unlikely to achieve the additional IOP lowering needed. This patient requires combination therapy, not monotherapy substitution. **Trabeculectomy (option D):** While this patient may eventually need surgery, the standard approach is to exhaust medical therapy first. She is on monotherapy only; combination medical therapy (2–3 topical agents) should be attempted before surgical intervention. Surgery is indicated when maximum tolerated medical therapy fails or in advanced/rapidly progressive disease — this patient does not yet meet that threshold. 
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