Optometry and Ocular Disease
Core framework
Approach every ocular disease question by asking three things: which tissue is involved, is it sight-threatening, and what is the time course. Master the classic presentations of blepharitis, hordeolum/chalazion, dry eye, keratoconus, cataract, glaucoma (open-angle vs angle-closure), anterior uveitis, retinal vascular occlusions, diabetic retinopathy, AMD, and optic neuropathies.
Concepts to know cold
- Anterior segment: distinguish bacterial, viral, and allergic conjunctivitis by discharge, laterality, and follicle vs papilla. Know the corneal signs of keratoconus (inferior steepening, Vogt striae, Fleischer ring) and the red-flag features of microbial keratitis (pain, photophobia, stromal infiltrate, hypopyon).
- Glaucoma: separate open-angle from angle-closure. Angle-closure has mid-dilated fixed pupil, shallow anterior chamber, and acute pain with halos; open-angle is insidious with cupping and field loss.
- Posterior segment: differentiate dry vs wet AMD (sudden metamorphopsia and hemorrhage = wet). Recognize CRVO (blood-and-thunder fundus) vs BRAO (pale retina, cherry-red spot).
Traps
Questions often swap laterality or time course. A painful red eye is rarely simple conjunctivitis. Do not confuse papilledema (bilateral, disc swelling with preserved acuity) with optic neuritis (pain on movement, acuity loss, afferent pupillary defect).
Rule of thumb
If a question describes a painful, photophobic red eye with reduced vision, think cornea or uveitis, not conjunctivitis, and act urgently.
Worked example
A 62-year-old reports sudden painless vision loss with a cherry-red spot and pale retina. The pale retina reflects ischemia of the inner retina; the cherry-red spot is preserved choroidal perfusion at the fovea. Answer: central retinal artery occlusion, an emergency.