ABO Ophthalmology cheat sheet

Corneal epithelium regenerates from limbal stem cells; limbal stem cell deficiency produces conjunctivalization, recurrent erosions, and a dull reflex.

Fuchs endothelial dystrophy: guttae on specular microscopy, Descemet folds, stromal edema worse on waking; hypertonic saline early, endothelial keratoplasty when visually significant.

Bacterial keratitis is a corneal emergency: scrape for culture before antibiotics, and treat contact-lens wearers with pseudomonal coverage (fluoroquinolone or fortified tobramycin/cefazolin).

Acanthamoeba keratitis: contact lens plus pain out of proportion, radial keratoneuritis, ring infiltrate; culture on non-nutrient agar with E. coli overlay.

Mooren ulcer is a painful peripheral corneal ulcer with overhanging edge and no scleral involvement; treat with topical steroid and systemic immunosuppression.

Herpes simplex epithelial keratitis: branching dendrite with terminal bulbs, rose bengal or fluorescein positive; debridement plus topical or oral antiviral.

Neurotrophic keratopathy is anesthetic and painless; treat with lubrication, bandage contact lens, and serum tears, avoiding topical anesthetics.

Pellucid marginal degeneration: inferior peripheral thinning 1-2 mm from limbus, against-the-rule astigmatism, no lipid deposits or vascularization.

Corneal ulcer with hypopyon plus severe pain and decreased vision requires same-day ophthalmology evaluation regardless of apparent size.

Open-angle glaucoma: optic disc cupping with neuroretinal rim loss, retinal nerve fiber layer thinning, and characteristic arcuate or nasal step field defects.

Acute angle-closure: mid-dilated fixed pupil, hazy cornea, IOP often >40 mmHg, nausea and halos; treat with topical beta-blocker, alpha-agonist, pilocarpine after IOP lowering, and systemic acetazolamide.

Normal-tension glaucoma: IOP in normal range but progressive glaucomatous damage; evaluate for nocturnal hypotension, sleep apnea, and vasospasm.

Prostaglandin analogs lower IOP most (25-33%) by increasing uveoscleral outflow; side effects include iris darkening, eyelash growth, and periorbital fat atrophy.

Beta-blockers reduce aqueous production and are contraindicated in asthma and heart block; avoid in patients with reactive airway disease.

Optic disc hemorrhage, beta-zone peripapillary atrophy, and thin central corneal thickness are risk factors for progression in open-angle glaucoma.

Angle recession after blunt trauma predisposes to unilateral glaucoma years later; examine the fellow eye for comparison of angle width.

Trabeculectomy failure risk increases with prior conjunctival surgery, young age, and African ancestry; mitomycin C improves success but raises hypotony risk.

Pseudoexfoliation glaucoma: dandruff-like material on lens capsule and pupillary margin, weak zonules, and rapid progression.

Central retinal artery occlusion: sudden painless monocular vision loss, cherry-red macula, boxcarring; it is a stroke equivalent requiring urgent systemic evaluation.

Branch retinal vein occlusion: sector flame hemorrhages, cotton-wool spots, and macular edema; anti-VEGF is first-line for vision-threatening edema.

Diabetic retinopathy: microaneurysms, dot-blot hemorrhages, hard exudates; proliferative disease shows neovascularization and requires panretinal photocoagulation or anti-VEGF.

Rhegmatogenous retinal detachment presents with flashes, floaters, and a curtain; a visible tear or subretinal fluid warrants urgent repair.

Macular hole: full-thickness defect with a cuff of subretinal fluid; vitrectomy with ILM peeling and gas tamponade is standard for stage 3-4.

Age-related macular degeneration: dry form shows drusen and geographic atrophy; wet form shows choroidal neovascular membrane and responds to anti-VEGF.

Retinopathy of prematurity screening: infants born <30 weeks or <1500 g are screened starting at 4-6 weeks postnatal age or 31 weeks postmenstrual age.

Vitreous hemorrhage in a diabetic patient with no view of the retina may require vitrectomy if nonclearing or associated with retinal detachment.

Optic neuritis: painful vision loss, reduced color vision, afferent pupillary defect, and a swollen or normal disc; multiple sclerosis association is common.

Giant cell arteritis: age >50, headache, jaw claudication, elevated ESR/CRP; give high-dose corticosteroids immediately and biopsy within 2 weeks.

Horner syndrome: ptosis, miosis, and anhidrosis; postganglionic lesions may show a dilated pupil after hydroxyamphetamine, and any new Horner warrants imaging.

Third nerve palsy with a dilated pupil suggests a compressive lesion such as aneurysm; urgent imaging is indicated.

Papilledema is bilateral disc swelling from raised intracranial pressure; it spares visual acuity early and requires neuroimaging and lumbar puncture.

Internuclear ophthalmoplegia: impaired adduction on the affected side and abducting nystagmus; a lesion in the medial longitudinal fasciculus, often MS or stroke.

Leber hereditary optic neuropathy: bilateral sequential painless central vision loss in a young man, with telangiectatic disc vessels early and optic atrophy later.

Afferent pupillary defect indicates an optic nerve or severe retinal lesion and is tested with the swinging flashlight.

Leukocoria differential includes retinoblastoma, congenital cataract, persistent fetal vasculature, Coats disease, and toxocariasis; retinoblastoma is the priority to exclude.

Congenital nasolacrimal duct obstruction: tearing and discharge in infancy; treat with massage, then probing if persistent beyond 12 months.

Amblyopia: reduced vision from abnormal visual experience; penalization or patching is most effective before age 7-8.

Esotropia: accommodative esotropia often responds to hyperopic correction; infantile esotropia requires surgical alignment by about 2 years.

Exotropia: intermittent exotropia may be managed with observation, over-minus lenses, or surgery if control deteriorates.

Congenital glaucoma: enlarged cornea (buphthalmos), tearing, photophobia, and elevated IOP; urgent surgical management is needed.

Retinoblastoma: white reflex, strabismus, or family history; enucleation for advanced disease, and genetic counseling for RB1 mutation.

Strabismus surgery: recession weakens a muscle and resection strengthens it; adjustable sutures allow postoperative adjustment.

Orbital cellulitis: fever, proptosis, pain, and restricted eye movement; requires urgent imaging and IV antibiotics, with surgical drainage if abscess forms.

Thyroid eye disease: lid retraction, proptosis, and restrictive strabismus; smoking cessation is the single most important modifiable risk factor.

Basal cell carcinoma: pearly nodule with telangiectasia, most common eyelid malignancy; Mohs surgery preserves tissue in the periocular region.

Chalazion is a lipogranuloma of the meibomian gland; initial treatment is warm compresses, and incision and curettage is used if persistent.

Dacryocystitis: tender medial canthal swelling from nasolacrimal duct obstruction; treat with antibiotics and dacryocystorhinostomy if recurrent.

Orbital compartment syndrome: vision loss, proptosis, and a tense orbit after trauma or surgery; emergent lateral canthotomy and cantholysis is sight-saving.

Ptosis: levator function >10 mm favors levator advancement; poor function may need frontalis suspension.

Orbital floor fracture: restricted upgaze, enophthalmos, and infraorbital numbness; surgery is indicated for entrapment or persistent diplopia.

Anterior uveitis: cells and flare in the anterior chamber, photophobia, and a miotic pupil; treat with topical steroids and cycloplegics.

HLA-B27-associated uveitis is often unilateral and recurrent; it is associated with ankylosing spondylitis and inflammatory bowel disease.

Posterior synechiae form between iris and lens; cycloplegics prevent adhesion and break early synechiae.

Toxoplasmosis retinochondritis: focal necrotizing retinitis adjacent to a pigmented scar; treat with pyrimethamine and sulfadiazine if vision-threatening.

Sympathetic ophthalmia: bilateral granulomatous panuveitis after penetrating trauma to one eye; enucleation within 2 weeks of injury reduces risk.

Sarcoidosis uveitis: mutton-fat keratic precipitates, iris nodules, and retinal periphlebitis; chest imaging supports diagnosis.

Behçet disease: recurrent oral and genital ulcers with hypopyon uveitis; systemic immunosuppression is required.

CMV retinitis: hemorrhagic retinitis with granular borders in immunocompromised patients; treat with systemic antivirals.

Nuclear sclerotic cataract causes gradual blurring and increased myopia; cortical cataract produces glare and spokes; posterior subcapsular cataract causes glare out of proportion to acuity.

Phacoemulsification uses ultrasound to emulsify the nucleus; posterior capsule rupture is the most common serious intraoperative complication.

Endophthalmitis: acute pain and vision loss after cataract surgery; treat with intravitreal antibiotics, and vitrectomy for severe cases.

Pseudophakic bullous keratopathy: corneal edema after surgery from endothelial damage; may require endothelial keratoplasty.

Intraocular lens power calculation uses axial length, keratometry, and A-constant; prior refractive surgery complicates biometry.

Capsular phimosis is anterior capsule contraction after surgery; Nd:YAG capsulotomy treats visually significant posterior capsule opacification.

Cataract surgery in pseudoexfoliation: weak zonules increase risk of capsular complications; consider capsular tension devices.

Congenital cataract with dense opacity requires surgery within the first weeks to months of life to prevent irreversible amblyopia.

Myopia is corrected with a diverging minus lens; hyperopia with a converging plus lens; astigmatism with a cylindrical lens.

LASIK creates a corneal flap and ablates stroma; PRK removes epithelium and ablates stroma, with slower recovery but no flap complications.

Contraindications to refractive surgery include active keratoconus, severe dry eye, and unstable refraction over the prior year.

Corneal ectasia after LASIK is a serious complication; screen with topography and pachymetry for forme fruste keratoconus.

Snellen 20/20 means a letter subtends 5 minutes of arc at 20 feet; 20/40 is the threshold for many driving standards.

Hyperopic LASIK steepens the central cornea; myopic LASIK flattens it.

Anisometropia can cause aniseikonia and amblyopia; refractive correction balances image size.

Presbyopia results from loss of accommodative amplitude; reading adds are prescribed to restore near vision.

Uveal melanoma: most common primary intraocular malignancy in adults; treat with plaque brachytherapy or enucleation, and monitor for metastasis to the liver.

Retinoblastoma: most common intraocular malignancy of childhood; histology shows Flexner-Wintersteiner rosettes.

Conjunctival melanoma arises from primary acquired melanosis; wide local excision with cryotherapy reduces recurrence.

Sebaceous carcinoma of the eyelid mimics chalazion and can pagetoid-spread; biopsy any recurrent chalazion.

Optic nerve glioma is associated with neurofibromatosis type 1; optic nerve sheath meningioma causes gradual vision loss and optociliary shunt vessels.

Lymphoma of the orbit or conjunctiva: salmon-patch appearance; biopsy and systemic staging are required.

Metastatic disease to the choroid is the most common intraocular malignancy overall; breast and lung are common primaries.

Squamous cell carcinoma of the conjunctiva is associated with UV exposure and HIV; it can invade the orbit if neglected.

Topical beta-blockers: reduce aqueous production; caution in asthma, bradycardia, and heart block.

Alpha-2 agonists (brimonidine): reduce aqueous production and increase uveoscleral outflow; cause allergic conjunctivitis and dry mouth.

Carbonic anhydrase inhibitors: reduce aqueous production; systemic acetazolamide causes paresthesias, metabolic acidosis, and kidney stones.

Topical corticosteroids: reduce inflammation but raise IOP and risk cataract and infection; monitor IOP with prolonged use.

Atropine and cyclopentolate are cycloplegic mydriatics; tropicamide produces mydriasis with shorter cycloplegia.

Phenylephrine is an alpha-agonist mydriatic; it can cause systemic hypertension and should be avoided in infants.

Timolol is a nonselective beta-blocker; betaxolol is beta-1 selective with less pulmonary effect but still caution in asthma.

Fluorescein angiography uses sodium fluorescein; adverse reactions include nausea and, rarely, anaphylaxis.

Diabetes: tight glycemic control reduces progression of retinopathy; HbA1c <7% is a common target.

Hypertension is a risk factor for retinal vascular disease; control reduces stroke and retinopathy risk.

Anticoagulation: do not routinely stop aspirin or warfarin for cataract surgery; individualize per procedural bleeding risk.

Perioperative endophthalmitis prophylaxis: topical povidone-iodine is the most effective single measure.

Local anesthetic systemic toxicity: treat with lipid emulsion; monitor for seizures and cardiac arrhythmia.

Sickle cell disease: hyphema and retinal ischemia are risks; avoid hypoxia and dehydration during surgery.

Pregnancy: avoid systemic tetracyclines and fluoroquinolones; topical beta-blockers require caution.

Herpes zoster ophthalmicus: treat with antivirals within 72 hours; consider vaccination for older adults.