Congenital and Developmental Cataracts

Intro & Etiology - Cloudy Beginnings

• Definition: Lens opacity at birth or early infancy, obstructing visual axis, potentially causing amblyopia.
• Significance: Leading cause of treatable childhood blindness. Early intervention (first 2-3 months) crucial for visual development.
• Etiology:
  • Genetic:
    • Autosomal Dominant (AD) most common for isolated cataracts.
    • AR, X-linked; syndromic (e.g., Down's, Lowe's).
  • Metabolic:
    • Galactosemia (""oil-droplet"" cataract).
    • Hypoglycemia, Hypocalcemia.
  • Intrauterine Infections:
    • 📌 TORCH: Toxoplasmosis, Other (Syphilis, VZV), Rubella (classic), CMV, Herpes.
  • Trauma: Rare (e.g., birth injury).
  • Idiopathic: ~30-50% of cases.

⭐ Most common inheritance for isolated congenital cataracts: Autosomal Dominant.

Morphology & Syndromes - Cataract Shapes & Links

• Associated Syndromes:
  • Lowe's Syndrome: Cataract (~50%), posterior lenticonus
  • Down's Syndrome (Trisomy 21): Flake-like, sutural, cerulean
  • Hallermann-Streiff: Membranous, microphthalmia
  • Congenital Rubella: Nuclear, total; "salt & pepper" fundus
  • Galactosemia: Oil-droplet (reversible early), zonular
  • Alport's Syndrome: Anterior lenticonus, PSC
  • Wilson's Disease: Sunflower cataract (copper)
  • Myotonic Dystrophy: Christmas tree (polychromatic), PSC

Clinical Features & Diagnosis - Spotting the Haze

• Symptoms (Parental/Pediatrician Concern):
  • Leukocoria (white pupil) - hallmark sign!
  • Poor visual fixation, nystagmus (involuntary eye movements), strabismus (misaligned eyes).
  • Photophobia (light sensitivity).
  • Absent or abnormal red reflex.
• Diagnostic Evaluation:
  • Visual Acuity: Age-appropriate methods (e.g., fixation preference, Teller cards).
  • Bruckner Test: Assesses symmetry of red reflexes.
  • Ophthalmoscopy (Direct/Indirect): To view red reflex, lens, and fundus.
  • Slit-lamp Examination: Detailed view of cataract morphology; opacity > 3mm or central is often visually significant.
  • B-scan Ultrasonography: If dense cataract obscures fundus view, to rule out posterior pathology.

⭐ Leukocoria in a child is an ocular emergency requiring urgent evaluation to exclude retinoblastoma and congenital cataract.

Management & Complications - Clearing the View

• Surgical Timing (Critical Window):
  • Bilateral significant cataracts: by 4-6 weeks of age.
  • Unilateral significant cataracts: by 6-8 weeks of age.
• Surgical Procedures:
  • Lensectomy (lens removal).
  • Anterior vitrectomy (common in infants, prevents PCO).
  • Primary Posterior Capsulotomy (PPC).
• IOL Implantation:
  • Primary (at surgery) vs. Secondary (later).
  • Challenges: Power calculation (growing eye); target slight hypermetropia.
• Amblyopia Management (CRUCIAL):
  • Aggressive patching of sound eye.
  • Optical correction: Aphakic glasses, contact lenses, IOL.
• Complications:
  • Glaucoma (most common serious long-term).
  • Posterior Capsular Opacification (PCO).
  • Retinal detachment, Strabismus, Nystagmus, Endophthalmitis.

⭐ The most common and serious long-term complication following congenital cataract surgery is secondary glaucoma.

High‑Yield Points - ⚡ Biggest Takeaways

• Leukocoria (white reflex) is a critical sign; urgent referral is mandatory.
• Amblyopia is the major risk; early surgery (e.g., <2 months for dense bilateral) is crucial.
• Lamellar cataract is the most common type of developmental cataract.
• Maternal rubella (1st trimester) causes pearly nuclear cataracts & microphthalmos.
• Galactosemia presents with an "oil-droplet" cataract, reversible with early dietary restriction.
• Hereditary cataracts are most commonly autosomal dominant.
• Posterior polar cataracts: high risk of posterior capsular rupture during surgery.