Primary angle closure is usually asymmetric and driven by pupil block in a short, hyperopic eye. When both eyes close at the same time, the patient is young or myopic, or there is a myopic shift, think of a secondary mechanism: ciliochoroidal effusion pushing the lens-iris diaphragm forwards.
Drug causes include topiramate and other sulfonamide-related medicines, typically within the first weeks of starting them. Inflammatory causes include VKH and posterior scleritis. In these eyes, miotics can worsen the closure and peripheral iridotomy may not help, while stopping the drug, cycloplegia and treating the inflammation are the mainstays. Ultrasound biomicroscopy or B-scan confirms the effusion.
- Suspect a secondary mechanism when angle closure is bilateral and simultaneous.
- Ask about recent topiramate or other sulfonamide-related drugs.
- Look for a myopic shift and a uniformly shallow anterior chamber.
- Avoid miotics when ciliochoroidal effusion is suspected.
- Confirm effusion with ultrasound biomicroscopy or B-scan.
Why it matters
The standard treatment for pupil block can make effusion-driven angle closure worse.
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