Glaucoma
Core concepts
Know the difference between open-angle and angle-closure mechanisms, and the anatomy of the angle (trabecular meshwork, Schlemm canal, scleral spur). Understand optic nerve head assessment: cupping, neuroretinal rim thinning, disc hemorrhage, and retinal nerve fiber layer loss. Know the major risk factors: elevated IOP, thin central corneal thickness, age, family history, and African ancestry. Master the medical classes: prostaglandin analogs (first-line, increase uveoscleral outflow, side effects of hypertrichosis and iris darkening), beta-blockers (avoid in asthma and heart block), alpha agonists (avoid in children), carbonic anhydrase inhibitors, and cholinergic agents. Know laser options: SLT for open angle, laser peripheral iridotomy for angle closure.
Traps
Questions test that IOP can be normal in glaucoma (normal-tension glaucoma) and that a thin cornea underestimates true IOP by standard tonometry. Another trap: distinguishing acute angle closure (mid-dilated pupil, corneal edema, nausea) from uveitis (miotic pupil, cells). Also know that prostaglandin analogs are avoided in uveitic glaucoma and in pregnancy.
Worked example / rule of thumb
A patient with a shallow anterior chamber, mid-dilated fixed pupil, and severe pain after dim light exposure has acute angle closure. Treat with IOP-lowering agents, topical steroid, and laser peripheral iridotomy to the fellow eye prophylactically. Rule of thumb: always examine the fellow eye in angle closure because the anatomy is bilateral.