# Congenital and Developmental Cataracts

## Introduction

Pediatric cataracts are a significant cause of preventable blindness worldwide, responsible for 5-20% of childhood blindness. **Congenital cataracts** are present at birth, while **developmental cataracts** appear during the first decade of life. Early diagnosis and appropriate management are critical to prevent irreversible deprivation amblyopia.

## Epidemiology

Incidence: 1-6 per 10,000 live births. Bilateral in approximately 60% of cases. Unilateral dense congenital cataracts carry the worst visual prognosis due to severe amblyopia. One-third idiopathic, one-third hereditary, one-third secondary to systemic disease or infection.

## Etiology

### Hereditary

**Autosomal dominant** -- most common inheritance pattern; variable expressivity. Mutations in crystallin genes (CRYAA, CRYBB2), connexin genes (GJA3, GJA8), and others. Family members should be examined with slit lamp.

### Intrauterine Infections (TORCH)

**Rubella** -- most common infectious cause worldwide; nuclear or total cataract, microphthalmos, glaucoma, pigmentary retinopathy. **Toxoplasmosis**, **CMV**, **HSV**, **syphilis**, varicella.

### Metabolic Disorders

**Galactosemia** -- oil-droplet cataract (central, refractile); reversible if galactose-free diet started early. **Galactokinase deficiency** -- lamellar cataract without systemic disease. **Lowe syndrome** (oculocerebrorenal) -- dense bilateral cataracts, glaucoma, renal tubular acidosis, intellectual disability. **Hypoglycemia**, **hypocalcemia** -- lamellar cataracts.

### Chromosomal Abnormalities

**Trisomy 21 (Down syndrome)** -- most common chromosomal association; cerulean, lamellar, or sutural cataracts. **Turner syndrome (45,X)**, trisomy 13, trisomy 18.

### Ocular Anomalies

**Persistent fetal vasculature (PFV)** -- unilateral microphthalmic eye with retrolental membrane. **Anterior segment dysgenesis**, aniridia.

![Slit-lamp photograph showing a dense white total congenital cataract in an infant](/images/ophthalmology/congenital-cataract-total.jpg)

## Morphologic Classification

**Nuclear** -- central, dense; often visually significant. **Lamellar (zonular)** -- most common morphology; concentric layers of opacity; may be visually significant depending on density. **Posterior subcapsular** -- often progressive; seen in steroid use, radiation. **Anterior polar** -- small, central; usually not amblyogenic; may be associated with anterior lenticonus. **Posterior polar** -- risk of capsule rupture during surgery. **Cerulean (blue dot)** -- typically not visually significant.

**Sutural** -- along Y-sutures; usually not amblyogenic. **Total/mature** -- entire lens opacified.

| Morphology | Location | Visual Significance | Key Association |
|---|---|---|---|
| Nuclear | Central lens | Usually significant | Rubella; hereditary |
| Lamellar (zonular) | Concentric layers | Variable (density-dependent) | Most common morphology; galactosemia |
| Posterior subcapsular | Posterior capsule | Progressive; significant | Steroids; radiation |
| Anterior polar | Anterior capsule center | Usually NOT amblyogenic | Anterior lenticonus |
| Posterior polar | Posterior capsule center | Variable | Risk of capsule rupture during surgery |
| Cerulean (blue dot) | Throughout cortex | Usually NOT significant | Autosomal dominant |
| Sutural | Along Y-sutures | Usually NOT amblyogenic | Hereditary |
| Total/mature | Entire lens | Dense; always significant | Various etiologies |

## Workup

### Unilateral Cataract

Often idiopathic or due to PFV, trauma, or ocular anomaly. Less likely to have systemic association. Evaluate for PFV (ultrasound), trauma history, anterior segment dysgenesis.

### Bilateral Cataracts

Systemic workup indicated: **Urine**: reducing substances (galactosemia), amino acids. **Serum**: calcium, phosphorus, glucose, galactose-1-phosphate uridylyltransferase. **TORCH titers** if clinical suspicion. **Karyotype** if dysmorphic features. Pediatric and genetics consultation.

## Surgical Management

### Timing

**Dense unilateral cataract**: surgery by age 4-6 weeks; delay increases risk of irreversible deprivation amblyopia. **Dense bilateral cataracts**: surgery by age 6-8 weeks; second eye within 1-2 weeks of first. **Partial cataracts**: observe if not visually significant; surgery when amblyopia develops.

### Surgical Technique

**Lensectomy with anterior vitrectomy** -- standard in infants. **Lens aspiration with posterior capsulotomy and anterior vitrectomy** -- prevents posterior capsule opacification (PCO), which occurs in nearly 100% of young children without this step. **IOL implantation**: debated in infants <6 months (IATS study); generally implanted age >= 1-2 years. IATS (Infant Aphakia Treatment Study): no significant difference in visual outcomes between contact lens aphakia and primary IOL implantation at age <7 months, but more adverse events and reoperations in IOL group.

### Optical Rehabilitation

**Aphakic correction** -- contact lens (preferred in infants) or spectacles. **IOL power calculation** -- target slight undercorrection in young children to account for myopic shift with eye growth. SRK/T or Holladay formulas; biometry challenging in small eyes.

![Intraoperative photograph of pediatric lensectomy with anterior vitrectomy](/images/ophthalmology/pediatric-lensectomy-intraop.jpg)

## Postoperative Management

Aggressive **amblyopia treatment** -- patching or atropine penalization of the fellow eye. Unilateral cases require intensive patching (up to 50% of waking hours initially) Monitor for **complications**: **Posterior capsule opacification** -- most common complication; Nd:YAG capsulotomy or surgical membranectomy. **Glaucoma** -- occurs in 10-25% of pediatric aphakic/pseudophakic eyes; lifelong risk. **Strabismus**, retinal detachment, endophthalmitis.

![RetCam photograph showing posterior capsule opacification after pediatric cataract surgery](/images/ophthalmology/pediatric-pco-retcam.jpg)

## Key Clinical Pearls

An absent or abnormal red reflex in an infant is an emergency requiring urgent ophthalmologic referral. Dense unilateral congenital cataracts must be operated within 6 weeks to prevent irreversible amblyopia. Bilateral cataracts require systemic workup including metabolic and infectious screening. Glaucoma can develop years to decades after pediatric cataract surgery -- lifelong monitoring is essential. The visual prognosis for unilateral congenital cataracts remains guarded despite optimal surgery and amblyopia therapy.

## References

1. Lambert SR, et al. A randomized clinical trial comparing contact lens and intraocular lens correction of monocular aphakia during infancy (IATS). Ophthalmology. 2014;121(6):1216-1222.
2. Medsinge A, Nischal KK. Pediatric cataract: challenges and future directions. Clin Ophthalmol. 2015;9:77-90.
3. Lloyd IC, et al. Neonatal cataract: aetiology, pathogenesis, and management. Eye. 1992;6:184-196.
4. American Academy of Ophthalmology. Pediatric Ophthalmology and Strabismus. BCSC Section 6. 2023-2024.