Glaucoma
This domain tests open-angle and angle-closure glaucoma, gonioscopy, medical and laser therapy, and recognition of optic nerve damage. The exam emphasizes that IOP is a risk factor, not the diagnosis.
Core glaucoma
- POAG: open angle, optic disc cupping, RNFL loss, and field defects. IOP may be normal.
- Gonioscopy grades the angle (Shaffer); Van Herick estimates peripheral depth at the slit lamp.
- First-line medical therapy: prostaglandin analog (latanoprost) increases uveoscleral outflow; beta blocker (timolol) reduces production but is risky in asthma and COPD; alpha agonist (brimonidine); carbonic anhydrase inhibitor (dorzolamide); pilocarpine.
- Laser and surgery: SLT for open angle; LPI for angle closure; trabeculectomy or MIGS for uncontrolled disease.
- Acute angle closure: painful red eye, mid-dilated pupil, corneal haze, IOP often above 40, nausea. Treat with acetazolamide, pilocarpine after IOP falls, mannitol, and LPI.
- Normal-tension glaucoma: consider sleep apnea, nocturnal hypotension, and vasospasm.
Worked example
A 65-year-old has IOP 28 mmHg, CDR 0.8, and a nasal step. Reasoning: open angle on gonioscopy plus disc and field damage confirms POAG. Start latanoprost nightly and monitor IOP and fields; do not treat the number alone.
Traps
Pilocarpine can worsen angle closure by shifting the lens-iris diaphragm. Timolol is risky in asthma. Prostaglandins darken the iris and lengthen lashes.