OMSB Ophthalmology (OEOPTH) cheat sheet

Acute angle-closure glaucoma: mid-dilated fixed pupil, corneal haze, IOP often >40 mmHg; immediate topical beta-blocker plus pilocarpine, IV acetazolamide, and osmotic agent; definitive treatment is laser peripheral iridotomy.

Bacterial keratitis: hypopyon, stromal infiltrate, contact lens wear is leading risk factor; corneal scrape for Gram stain and culture before hourly fortified topical antibiotics (cefazolin 5% plus tobramycin 1.4%).

Primary open-angle glaucoma: open angle with optic disc cupping (cup-to-disc >0.6, neuroretinal rim thinning, disc hemorrhage) and visual field defect; first-line IOP lowering with prostaglandin analog once daily at night.

Retinopathy of prematurity screening: examine infants born <30-32 weeks gestation or <1500 g birth weight; first exam at 4-6 weeks postnatal age or 31-33 weeks postmenstrual age, whichever is later.

Leukocoria differential: retinoblastoma, congenital cataract, persistent fetal vasculature, Coats disease, toxocariasis, retinal detachment; any leukocoria warrants urgent fundus exam and imaging.

Endophthalmitis after cataract surgery: presents within days with pain, hypopyon, vitritis; treat with intravitreal vancomycin plus ceftazidime (or amikacin) after vitreous tap; vitrectomy if visual acuity is light perception only.

Papilledema versus papillitis: papilledema is bilateral, spares initial visual acuity, and shows enlarged blind spot; unilateral disc edema with early acuity loss suggests optic neuritis, often linked to multiple sclerosis.

Corneal abrasion management: topical antibiotic prophylaxis, no patching for contact lens-related injuries; avoid topical anesthetics; refer if infiltrate, hypopyon, or worsening pain develops.

Cataract surgery timing: operate when visual symptoms impair daily function; biometry with IOL power calculation (SRK/T for axial length >22 mm, Hoffer Q for short eyes) guides lens selection.

Diabetic retinopathy grading: nonproliferative stages by microaneurysms, dot-blot hemorrhages, hard exudates, cotton wool spots; proliferative disease defined by neovascularization at disc or elsewhere, treated with panretinal photocoagulation.

Macular edema in diabetes: center-involving edema responds to intravitreal anti-VEGF (ranibizumab, aflibercept, bevacizumab); focal/grid laser for non-center-involving edema.

Retinal detachment: rhegmatogenous detachment shows a horseshoe tear with subretinal fluid, positive Seidel test not applicable; pneumatic retinopexy, scleral buckle, or pars plana vitrectomy depending on configuration.

Amblyopia treatment: occlusion therapy (patching) or atropine penalization after refractive correction; critical period ends around age 8-10, so early detection at preschool vision screening is essential.

Strabismus: esotropia with onset before 6 months is infantile; acquired esotropia with diplopia in adults may indicate sixth nerve palsy, thyroid eye disease, or myasthenia gravis.

Thyroid eye disease: proptosis, lid retraction, restrictive strabismus (inferior rectus most common), optic neuropathy risk; smoking cessation and selenium in mild disease, steroids or orbital decompression in severe disease.

Ocular trauma: chemical burn requires immediate copious irrigation with normal saline for at least 30 minutes, check pH, and refer for alkali injury which is more severe than acid.