Glaucoma
Core concepts
Separate open-angle from angle-closure disease and understand the pathophysiology of each. Know the optic nerve head signs: cupping, rim thinning, disc hemorrhage, bayoneting, and retinal nerve fiber layer loss. Understand IOP as the only modifiable risk factor and the role of central corneal thickness in risk assessment. Learn the major drug classes, their mechanisms, and their systemic side effects: prostaglandin analogs (periorbital fat atrophy, iris darkening), beta-blockers (bronchospasm, bradycardia), alpha agonists (follicular conjunctivitis, CNS depression in children), carbonic anhydrase inhibitors (metabolic acidosis, paresthesias), and cholinergic agents (miosis, brow ache).
Traps
Acute angle-closure questions often hinge on the immediate step: lower IOP medically and definitively with laser peripheral iridotomy, not surgery first. Do not give pilocarpine before IOP is lowered in acute attack (ischemic iris won't respond). Beta-blockers are contraindicated in asthma and heart block. Remember that normal-tension glaucoma exists and is not "no glaucoma."
Rule of thumb
In angle closure, treat the fellow eye with prophylactic iridotomy too. In any glaucoma patient with a new disc hemorrhage, suspect progression even if IOP looks controlled.
Worked example
A patient on timolol presents with wheezing and a heart rate of 48. The most likely cause is systemic absorption of the beta-blocker; counsel on punctal occlusion and consider switching classes.