ICO Clinical Ophthalmology (Advanced) cheat sheet

Keratoconus: inferior steepening, asymmetric bow-tie, scissoring on retinoscopy; slit-lamp signs are Vogt striae (resolve with pressure), Fleischer ring (iron at cone base), Munson sign; diagnosis is topography/tomography-based, not refraction alone.

Acute angle-closure: IOP often >40 mmHg with mid-dilated fixed pupil, corneal edema, shallow anterior chamber; first-line IOP lowering with topical beta-blocker plus alpha-agonist and systemic acetazolamide or hyperosmotic; definitive treatment is laser peripheral iridotomy.

Primary open-angle glaucoma progression is judged by structural (RNFL/optic disc) and functional (visual field) concordance; IOP is the only modifiable risk factor, with target reduction commonly 20-30% from baseline.

Diabetic retinopathy grading: mild NPDR = microaneurysms only; moderate = more than mild but less than severe; severe NPDR = 4-2-1 rule (hemorrhages in 4 quadrants, venous beading in 2+, IRMA in 1+); PDR = neovascularization or vitreous/preretinal hemorrhage.

Central retinal artery occlusion: sudden painless monocular vision loss, afferent pupillary defect, cherry-red spot, retinal whitening; it is a stroke equivalent requiring urgent systemic evaluation for embolic source.

Giant cell arteritis: age over 50, new headache, jaw claudication, scalp tenderness, elevated ESR/CRP; treat with high-dose systemic corticosteroid immediately before biopsy, since vision loss in the fellow eye is a major risk.

Papilledema versus papillitis: papilledema is bilateral, preserves visual acuity until late, and shows enlarged blind spot; optic neuritis is usually unilateral with pain on eye movement, color desaturation, and an afferent pupillary defect.

Amblyopia treatment window: cortical plasticity declines after roughly age 7-9 but treatment can still be effective in older children and adults; occlusion dose and compliance matter more than absolute age cutoff.

Uveitis anterior cell grading uses standardized slit-lamp fields; hypopyon indicates severe inflammation and warrants urgent workup for infection, HLA-B27 disease, or Behçet disease.

Retinal detachment: rhegmatogenous shows a corrugated, mobile flap with a demarcation line and photopsia; exudative shows shifting subretinal fluid without a break; treatment differs fundamentally (surgery versus medical/systemic workup).

Endophthalmitis after cataract surgery: acute presentation within days with pain, hypopyon, and vitritis; intravitreal antibiotics are first-line, with vitrectomy for severe cases or no improvement.

Corneal ulcer: scrape for Gram stain and culture before antibiotics in sight-threatening cases; contact lens wearers need Pseudomonas and Acanthamoeba coverage considered.

Ocular surface squamous neoplasia can masquerade as chronic unilateral conjunctivitis or a gelatinous limbal lesion; any non-healing lesion requires biopsy rather than prolonged topical steroids.

Thyroid eye disease: active phase shows inflammatory signs (pain, redness, swelling) and is treated medically; rehabilitative surgery (orbital decompression, strabismus, eyelid) is reserved for the stable inactive phase.

Retinopathy of prematurity screening thresholds are based on gestational age and birth weight, not current weight alone; plus disease and zone I involvement drive treatment urgency with anti-VEGF or laser.

Optic disc cupping is not diagnostic of glaucoma; disc size, rim pattern, and progression over time are more informative than a single cup-to-disc ratio.