Ophthalmology
Domain orientation
The ICO Advanced ophthalmology section tests whether you can move from a symptom to a defensible diagnosis and management plan across cornea, glaucoma, retina, uveitis, neuro-ophthalmology, pediatrics, and oculoplastics. Questions favor integrated reasoning: a disc finding may require a vascular, inflammatory, or compressive explanation; a red eye may hinge on contact-lens history or anterior chamber depth.
Core rules
- Classify vision loss by onset (sudden vs progressive), laterality, pain, and whether the problem is ocular or afferent. A relative afferent pupillary defect points to optic nerve or extensive retinal disease, not media opacity.
- In acute unilateral optic disc edema, distinguish arteritic from non-arteritic disease before attributing it to NAION. Age over 50, jaw claudication, scalp tenderness, elevated ESR/CRP, or visual loss in the fellow eye raise giant cell arteritis probability.
- Do not treat a swollen disc with unilateral optic neuropathy as NAION if pain on eye movement, bilateral sequential loss, or systemic symptoms are present; those features suggest arteritis or another inflammatory/compressive process.
- For corneal disease, ask about contact-lens wear and use slit-lamp findings (infiltrate size, hypopyon, endothelial plaque) to decide urgent scraping and fortified antibiotics versus routine topical therapy.
Worked example
A 74-year-old woman reports sudden painless loss of vision in the right eye. VA is 20/200 right and 20/20 left; there is a right RAPD and a swollen right optic disc. She has scalp tenderness and an ESR of 78 mm/h. The reasoning: sudden unilateral painless loss with disc edema suggests NAION, but age, scalp tenderness, and markedly elevated ESR shift the diagnosis to giant cell arteritis with arteritic anterior ischemic optic neuropathy. Management is urgent high-dose systemic corticosteroid and temporal artery biopsy, not observation.
Traps
Missing a fellow-eye afferent defect; calling all disc edema NAION; ignoring contact-lens history in a corneal ulcer; and forgetting that pupil findings localize disease before imaging does.