Ophthalmology — red eye, vision loss, glaucoma

◆Red eye differential

• •Conjunctivitis bacterial: purulent discharge, eyes 'glued shut' in morning; topical erythromycin (kids) or fluoroquinolone (adults, contact lens wearers — cover Pseudomonas)
• •Conjunctivitis viral: watery discharge, preauricular lymphadenopathy, often bilateral; supportive (highly contagious — adenovirus)
• •Conjunctivitis allergic: itching is prominent + bilateral; topical antihistamines
• •Acute angle-closure glaucoma: severe pain + halos + nausea + mid-dilated FIXED pupil + cloudy cornea + ↑↑ IOP; emergency — pilocarpine, timolol, acetazolamide, mannitol, then laser iridotomy
• •Corneal abrasion: pain, foreign body sensation, photophobia; fluorescein stain shows defect; topical antibiotic; NO eye patch (Pseudomonas risk in contact lens wearer)
• •Uveitis/iritis: pain + photophobia + ciliary flush (perilimbal redness) + cells in anterior chamber; associations: HLA-B27, sarcoid, JIA, IBD, syphilis; topical steroids + cycloplegic
• •Scleritis: severe deep pain, photophobia; associated RA, GPA; systemic NSAIDs/steroids; episcleritis is milder and self-limited
• •Keratitis: corneal inflammation; HSV (dendritic ulcer on fluorescein) → acyclovir; bacterial (esp. contact lens) → topical antibiotics + URGENT ophtho

◆Acute vision loss

• •Central retinal artery occlusion (CRAO): sudden painless monocular vision loss; cherry-red spot on fundus; ophthalmic emergency — ocular massage, anterior chamber paracentesis, work up emboli + GCA
• •Central retinal vein occlusion (CRVO): sudden painless less severe vision loss; 'blood and thunder' fundus (diffuse hemorrhages, dilated tortuous veins); ↑ risk DM, HTN, glaucoma
• •Retinal detachment: floaters → flashes → 'curtain coming down' → vision loss; risk factors high myopia, trauma, prior cataract surgery; URGENT ophtho for surgery
• •Vitreous hemorrhage: floaters + decreased vision; DM (proliferative retinopathy), trauma; observe vs vitrectomy
• •Optic neuritis: subacute vision loss + pain with eye movement; afferent pupillary defect; classic for MS — get MRI brain; IV steroids accelerate recovery
• •Amaurosis fugax: TIA — transient monocular vision loss ('curtain'); carotid stenosis source; carotid Doppler + antiplatelet
• •Giant cell arteritis: vision loss + headache + jaw claudication + ↑ ESR + age >50 — START STEROIDS BEFORE biopsy

◆Glaucoma

• •Open-angle (chronic): asymptomatic until late, cupping of optic disc (cup:disc >0.6), visual field defects; screening tonometry + fundoscopy; treat: latanoprost (PGF analog) first-line, then β-blocker drops (timolol), then surgery
• •Acute angle-closure: severe pain, halos, fixed mid-dilated pupil, cloudy cornea, ↑↑ IOP, nausea; emergency — DON'T dilate eyes for fundoscopy first
• •Treatment acute angle-closure: pilocarpine + timolol + acetazolamide + mannitol; then LASER PERIPHERAL IRIDOTOMY (definitive)
• •Triggers for acute angle-closure: dim light (mydriasis), anticholinergics, sympathomimetics

◆Diabetic & hypertensive retinopathy

• •Diabetic retinopathy — yearly dilated exam from diagnosis (T2DM) or 5 yr after diagnosis (T1DM)
• •Non-proliferative DR: microaneurysms, dot/blot hemorrhages, hard exudates, cotton wool spots
• •Proliferative DR: neovascularization → vitreous hemorrhage, traction retinal detachment; treat with PAN-RETINAL PHOTOCOAGULATION + anti-VEGF (bevacizumab, ranibizumab)
• •Diabetic macular edema: anti-VEGF intravitreal
• •Hypertensive retinopathy: arteriolar narrowing → AV nicking → flame hemorrhages, cotton wool spots → papilledema (malignant HTN)

◆Other key topics

• •Age-related macular degeneration: central vision loss; dry (drusen, slow) vs wet (neovascular, fast); wet AMD → anti-VEGF injections
• •Cataract: gradual painless vision loss with glare; risk factors age, steroids, diabetes; treat: surgical removal + IOL
• •Orbital cellulitis: pain with eye movement, proptosis, vision changes — EMERGENCY (CT, IV antibiotics, possible surgery)
• •Preseptal cellulitis: anterior to orbital septum, no eye movement pain or proptosis; oral antibiotics
• •Optic disc swelling (papilledema): bilateral → ↑ ICP; unilateral → optic neuritis or AION
• •Horner syndrome: ptosis + miosis + anhidrosis from sympathetic disruption (Pancoast tumor, carotid dissection, brainstem stroke)
• •Marcus Gunn pupil (RAPD): afferent pupillary defect — optic nerve disease

Red eye quick differential