Glaucoma
Core concepts
Understand aqueous dynamics and intraocular pressure regulation. Classify glaucoma: open-angle, angle-closure, secondary, and congenital. Know the diagnostic tests: tonometry, gonioscopy, optic disc assessment, visual fields, and OCT. Recognise glaucomatous disc changes (cupping, neuroretinal rim thinning, disc haemorrhage) and field defects (arcuate, nasal step, paracentral). Learn medical therapy classes and mechanisms: prostaglandin analogues, beta-blockers, alpha agonists, carbonic anhydrase inhibitors, and cholinergic agents. Understand laser and surgical options (trabeculoplasty, trabeculectomy, drainage devices).
Traps
Examiners test that IOP is not diagnostic alone; normal-tension glaucoma exists. Distinguish open-angle from angle-closure on gonioscopy. Remember prostaglandin analogues cause iris darkening and eyelash growth. Beta-blockers are contraindicated in asthma. Do not confuse cupping from glaucoma with physiologic cupping.
Worked example
A patient has IOP 28 mmHg, open angles, and a nasal step on field testing. Diagnosis: primary open-angle glaucoma. Start a prostaglandin analogue and monitor. Rule of thumb: treat the disc and field, not just the pressure.