Congenital Cataract

Definition And Epidemiology

Visible lenticular opacity present since birth.
Impairs visual acuity and obstructs clear view of fundus.
Occurs as unilateral or bilateral, symmetric or asymmetric.
Incidence represents 2 to 13 per 10,000 live births.
Low birthweight infants weighing 2,500 grams or less exhibit three to fourfold increased risk.
Presents as isolated defect in 60 percent, syndromic in 22 percent, and associated with unrelated major birth defects in remaining cases.

Etiology Category	Specific Conditions	Clinical Characteristics
Genetic And Chromosomal	Trisomy 13, 18, 21; Turner syndrome; Autosomal dominant traits.	Approximately 35 genes identified; crystallin gene variants represent most frequent etiology.
Congenital Infections	Toxoplasmosis, cytomegalovirus, syphilis, rubella, herpes simplex.	Often accompanied by microphthalmos, pigment epithelial mottling, and systemic anomalies.
Metabolic Disorders	Galactosemia, Lowe syndrome, Cerebrotendinous xanthomatosis.	Galactosemia produces oil droplet appearance; Lowe syndrome features dense bilateral opacities with glaucoma.
Developmental Variants	Persistent pupillary membrane, Mittendorf dot, Prematurity.	Prematurity causes transient vacuoles in Y sutures; hyaloid remnants cause focal capsule opacities.
Maternal Factors	Diabetes mellitus.	Congenital lens opacities occur in children of diabetic and prediabetic mothers.

Classic infantile galactosemia causes zonular cataracts with haziness of perinuclear layers.
Galactose-1-phosphate uridyltransferase deficiency drives oil droplet cataract formation.
Early dietary intervention with galactose-free diet reverses early lens changes.
Cerebrotendinous xanthomatosis causes childhood cataracts alongside chronic diarrhea and neurologic impairment.
Prompt treatment with chenodeoxycholic acid prevents permanent neurologic decline.

Incomplete regression of primitive hyaloid vascular system leaves Mittendorf dot on posterior capsule.
Persistent pupillary membrane strands cause anterior capsule opacities.
Congenital opacities of this type typically remain stationary and rarely reduce vision.

Red reflex testing reveals white reflex, dark spots, or absent reflection.
Direct ophthalmoscopy views optic disc and macula through undilated pupil.
Slit-lamp biomicroscopy determines precise depth and localization within lens layers.
Cycloplegic drops facilitate thorough peripheral retinal examination.

Visually significant opacities demand urgent surgical treatment to prevent irreversible sensory deprivation amblyopia.
Functional success peaks when operated within first few weeks of life.
Procedure involves aspiration and surgical removal of opaque lens material.

Optical correction of resultant aphakic refractive error remains essential.
Intraocular lens implantation serves as mainstay for children over 2 years of age.
Intraocular lenses generally avoided in children under 2 years due to changing lens power requirements and rapid eyeball growth.
Very young children retain capsule rim for subsequent secondary intraocular lens implantation.
Contact lenses provide highly effective temporary optical rehabilitation for infants.
Multicenter trials demonstrate higher intraoperative complications and adverse events with primary intraocular lenses in very young infants compared to contact lenses.

Patching therapy of sound eye mandatory for unilateral cases.
Treatment of sensory deprivation amblyopia represents most demanding and difficult step in visual rehabilitation.

Persistent amblyopia represents most common cause of poor visual recovery.
Aphakic glaucoma develops in up to 25 percent of children undergoing early cataract surgery.
Additional complications include inflammatory sequelae, secondary membranes, retinal detachment, and changes in axial length.
Overall prognosis depends on age at onset, age at intervention, duration of amblyopia, and associated ocular anomalies like microphthalmia or optic atrophy.