Glaucoma
Core concepts
Understand aqueous dynamics and the difference between open-angle and angle-closure glaucoma. Know that open-angle glaucoma is usually asymptomatic until late, while angle closure presents acutely with pain, halos, and a mid-dilated fixed pupil. Recognise risk factors: age, family history, African ancestry, myopia (for open angle), hyperopia and shallow anterior chamber (for angle closure).
Diagnosis includes IOP, gonioscopy, optic disc assessment (cup-to-disc ratio, neuroretinal rim), and visual fields. Know that IOP is a risk factor, not a diagnostic criterion. Understand the principles of treatment: lowering IOP with drops, laser (SLT for open angle, LPI for angle closure), and surgery (trabeculectomy, drainage devices).
Traps
- Assuming normal IOP excludes glaucoma (normal-tension glaucoma exists).
- Forgetting that angle closure needs urgent IOP lowering and LPI.
- Confusing SLT (open angle) with LPI (angle closure).
- Missing that visual field loss is typically arcuate and respects the horizontal midline.
Rule of thumb
If the anterior chamber is shallow and the patient has acute pain with halos, treat as acute angle closure until proven otherwise.
Worked example
A hyperopic patient presents with severe pain, halos, and a fixed mid-dilated pupil. Diagnose acute angle closure; start topical and systemic IOP-lowering therapy and perform laser peripheral iridotomy.