👁️ Chapter 32: Eye Disorders

Nelson's Pediatric Symptom-Based Diagnosis | Amblyopia · Strabismus · Leukocoria · Retinoblastoma · Congenital cataracts · Glaucoma · Red eye · Orbital cellulitis · Neuro-ophthalmology

🔍 Eye Disorders in Children: Key Concepts

👁️ Amblyopia (lazy eye)
Unilateral/bilateral vision loss from abnormal visual experience in critical period (<6y). Causes: strabismus, anisometropia, deprivation (cataract, ptosis). Treatment: patching, atropine, correct underlying cause.
🔄 Strabismus
Misalignment. Esotropia (crossing), exotropia (wall-eyed). Infantile esotropia by 6mo; accommodative esotropia from hyperopia. Cover test, corneal light reflex. Amblyopia risk → treat early.
⚪ Leukocoria (white pupil)
Emergency: retinoblastoma (life-threatening), congenital cataract, Coats disease, ROP, PHPV. Red reflex exam mandatory. Retinoblastoma: calcifications on CT/ MRI, genetic counseling.
👶 Congenital cataracts
Bilateral: metabolic (galactosemia), genetic, TORCH. Unilateral: idiopathic, PHPV. Remove within first 6-8 weeks to prevent irreversible amblyopia. Aphakic contact lenses or IOL.
🔵 Congenital glaucoma
Triad: epiphora, photophobia, blepharospasm, cloudy enlarged cornea (buphthalmos). Elevated IOP. Surgical treatment (goniotomy/trabeculotomy).
🟡 Red eye differential
Viral conjunctivitis (watery, preauricular node), bacterial (purulent), allergic (itching), keratitis, uveitis, angle-closure glaucoma, orbital cellulitis (proptosis, EOM limitation).

💡 Key takeaway: Red reflex screening in newborns and children detects leukocoria, cataracts, retinoblastoma. Strabismus and anisometropia cause amblyopia — treat before age 7. Leukocoria = immediate ophthalmology referral. Orbital cellulitis requires IV antibiotics and imaging to rule out subperiosteal abscess.

🩺 Clinical Approach to Pediatric Eye Disorders

🔹 Step 1: Newborn eye screening (red reflex)
• Perform in all newborns before discharge. Darken room, use direct ophthalmoscope.
• Normal: symmetric orange-red reflex. Abnormal: white (leukocoria), dull, asymmetric, or dark spots.
• Abnormal red reflex → emergent ophthalmology referral (retinoblastoma, cataract, Coats).
🔹 Step 2: Vision screening at well-child visits
• Birth-6mo: fix and follow, blink to light. Refer if no tracking by 3mo.
• 3-5y: visual acuity with Lea symbols or HOTV (20/40 acceptable at 3-4y, 20/30 at 5y).
• Photoscreening for preverbal children at high risk.
🔹 Step 3: Strabismus evaluation
• Corneal light reflex (Hirschberg): symmetric = aligned; asymmetric = strabismus.
• Cover test: eye moves to fixate = tropia.
• Any constant strabismus after 3-4 months → refer ophthalmology to prevent amblyopia.
🔹 Step 4: Red eye differential and emergency signs
• Red flags: severe pain, photophobia, decreased vision, corneal opacity, ciliary flush, fixed pupil, proptosis.
• Conjunctivitis: purulent (bacterial) vs watery (viral) vs itching (allergic).
• Orbital cellulitis: proptosis, painful EOM, vision loss → CT orbit, IV antibiotics.
🔹 Step 5: Leukocoria work-up
• Immediate ophthalmology referral. B-scan ultrasound, CT/MRI to detect calcifications (retinoblastoma).
• Retinoblastoma: most common malignant ocular tumor; sporadic or familial (RB1 gene).
• Other causes: PHPV, Coats disease, ROP, toxocariasis.