Congenital Cataracts: Complete Guide to Causes, Symptoms, Diagnosis, and Treatment

A congenital cataract is a clouding of the eye’s natural lens present at birth or shortly thereafter. The lens becomes opaque, blocking or distorting visual information.

Clear images are essential for brain development in infancy. Early obstruction can disrupt normal visual maturation and may cause amblyopia, a permanent reduction in vision that can persist even after cataract removal.

Congenital cataracts can be:

Unilateral (one eye): more likely to cause severe amblyopia if untreated
Bilateral (both eyes): often linked to genetic or metabolic disorders
Partial or total, stationary or progressive

Congenital cataracts affect approximately 1 in 3,000 babies, either at birth or within the first year of life.

Why Congenital Cataracts Matter

In adults, cataracts typically develop gradually and can be easily removed, often with excellent outcomes.
In infants, cataracts are an ophthalmic emergency. The visual system develops rapidly during the first few months, known as the critical period for visual development.

If light does not reach the retina during this period, the visual cortex cannot mature properly. Even with later surgery, full vision may not be restored.

Early detection and treatment, ideally within the first 6 to 10 weeks, can make a significant difference between lifelong blindness and normal vision.

How the Eye Develops Before Birth

Understanding prenatal eye development helps explain the causes of congenital cataracts.

Around the 4th week of gestation, the optic vesicle comes into contact with the surface ectoderm, forming the lens placode.
By the 6th week, this placode folds inward to create the lens vesicle, which separates from the surface to become the primitive lens.
Between the 8th and 12th weeks, lens fibers form from the back wall and fill the vesicle, creating the embryonic lens nucleus.

Disruptions during these stages, including infection, genetic factors, or metabolic issues, can cause structural or protein abnormalities that result in cataracts.

Main Causes of Congenital Cataracts

Congenital cataracts have many causes. The main distinction is whether the cataract is isolated or part of a systemic condition. Identifying the underlying cause is essential because it guides treatment and helps manage complications. A multidisciplinary evaluation by a pediatrician, geneticist, and ophthalmologist ensures optimal care. It also helps counsel families about the risks of recurrence and prognosis.

1. Genetic and Hereditary Factors

Approximately 30–50% of congenital cataracts are genetic.
They can occur:

As an isolated lens defect
As part of a syndrome involving other organs (eyes, skeleton, kidneys, nervous system)
Autosomal dominant inheritance is the most common pattern, though other inheritance modes are possible.

Commonly affected genes influence crystallin proteins, membrane transporters, and transcription factors essential for lens transparency.
A family history of childhood cataracts, consanguinity, or known genetic disorders increases the risk.

Examples of syndromic associations:

Down syndrome (trisomy 21)
Marfan and Weill-Marchesani syndromes (connective tissue disorders)
Stickler syndrome (collagen abnormality with increased risk of retinal detachment)
Lowe syndrome (ocular, renal, and neurological disorder)
Steinert myotonic dystrophy (muscular dystrophy with cataracts)

2. Infectious Causes (TORCH Infections)

Maternal infections during pregnancy can cross the placenta and damage the developing lens.
The main culprits are grouped under the acronym TORCH:

Toxoplasmosis
Other infections (syphilis, varicella-zoster, parvovirus B19)
Rubella (also known as German measles) is the most common cause of this condition.
Cytomegalovirus (CMV)
Herpes simplex virus (HSV)

Rubella infection during the first trimester is especially harmful, leading to classic congenital rubella syndrome, which includes cataracts, deafness, and heart defects.
Vaccinating women before pregnancy is the most effective prevention.

3. Metabolic disorders, such as galactosemia or calcium imbalances.

Galactosemia: inability to process galactose leads to accumulation of toxic byproducts in the lens, resulting in rapid bilateral cataracts
Hypocalcemia or hypophosphatemia
Aminoaciduria or ferritin storage disorders
Hypoparathyroidism
Diabetes in infants (rarely)

Early identification of these disorders enables systemic treatment and helps prevent recurrence.

Clinical Signs and Symptoms

Parents are often the first to notice a white appearance in their child’s eye or that the baby does not fixate on or follow objects.

Key warning signs:

Leukocoria: a white or gray pupil reflex in place of the normal red reflex
Strabismus (crossed eyes): due to unequal vision
Nystagmus: rapid, involuntary eye movements (indicating early, severe visual deprivation)
Poor tracking or absent eye contact
Eye pressing or rubbing (known as the Franceschetti sign)
Delayed visual milestones

Diagnosis and Medical Evaluation

Diagnosis involves multiple steps:

1. Parental Interview

The ophthalmologist asks about:

Pregnancy history (infections, medications, radiation exposure)
Delivery and neonatal health
Family history or consanguinity
Age at which abnormal signs appeared

2. Ophthalmic Examination

In infants, the examination is performed under sedation or anesthesia:

Visual behavior (fixation, following light, response to faces)
Corneal size and clarity
Iris structure and pupil reactions
Lens examination with a slit lamp or a direct ophthalmoscope
Fundus evaluation (to rule out retinal tumors, including retinoblastoma)
Intraocular pressure measurement

3. Imaging and Tests

Ultrasound (B-scan): explores retina and vitreous when the lens is opaque
Ultrabiomicroscopy (UBM): analyzes anterior segment anatomy
Electrophysiology (ERG/VEP): checks retinal and optic nerve function
Laboratory workup: TORCH serology, galactosemia screening, calcium/phosphate/glucose/ferritin levels
Genetic karyotyping: if associated anomalies or family history exist

Types and Classification of Congenital Cataracts

Congenital cataracts are classified based on their location, appearance, and underlying cause. Main types include nuclear, lamellar, cortical, anterior polar, posterior polar, and total cataracts. Each type affects a specific part of the lens and has distinct implications for vision and management. Accurate classification guides treatment and helps predict prognosis. Recognizing patterns can also indicate underlying genetic or metabolic disorders.

Total	Entire lens opaque	Complete blindness; urgent surgery
Nuclear	Central dense core	Mild to moderate, often hereditary
Lamellar / Zonular	Rings around fetal nucleus	Variable, common genetic type
Cerulean	Blue-white cortical dots	Minimal impact, often stable
Coralliform	Crystalline, coral-like	Progressive and visually significant
Anterior polar	Small white spot at front	Often harmless
Posterior polar	Dense opacity at back	Dangerous — can cause early amblyopia
Subcapsular	Beneath capsule	May obscure central vision quickly
Composite	Mixed features	Requires individualized evaluation

Associated Conditions and Syndromes

In addition to ocular causes, congenital cataracts may be part of multisystem diseases involving:

Kidneys (Lowe, Alport syndromes)
Heart (Sengers syndrome)
Muscles and skeleton (epiphyseal dysplasia, myotonic dystrophy)
Skin and teeth (Cockayne, Rothmund-Thomson syndromes)
Craniofacial dysmorphisms (Hallermann-Streiff, Smith-Lemli-Opitz)

Recognizing these associations is essential for genetic counseling and comprehensive management. and How to Treat

Congenital cataracts that block the visual axis require urgent surgical intervention.

Unilateral, total	Before 6 weeks of age	Prevent irreversible amblyopia
Bilateral, total	Before 8–10 weeks	Each eye operated a few days apart
Partial	Observe; operate if vision < 3/10	Regular follow-up essential

Treatment Options

Treatment for congenital cataracts is individualized based on the cataract’s size, location, density, and the child’s age and health. Small, non-progressive cataracts that do not affect the visual axis may be monitored. Visually significant cataracts typically require prompt surgery to prevent irreversible loss of vision. A specialized team determines the timing, surgical approach, and method of optical correction to achieve the best visual outcomes.

1. Preoperative Management

Visual stimulation and amblyopia therapy may be started for partial cataracts.
A general pediatric evaluation ensures the baby is fit for anesthesia.

2. Surgical Techniques

The goal is to remove the opaque lens and restore a clear visual pathway.

Steps include:

Limbal incision
Gentle capsulorhexis (anterior + posterior)
Phacoaspiration of the lens
Anterior vitrectomy to prevent secondary cataract
Intraocular lens (IOL) implantation when anatomically possible
Suturing is required in infants to prevent wound leakage.

IOL power is intentionally undercorrected to compensate for eye growth:

60% of the calculated value at 0–3 months
80–90% at 6 months–2 years
Full correction after 4 years

3. Postoperative Care

Topical therapy: antibiotic, steroid, and anti-inflammatory eye drops for one month
Systemic steroids: prescribed for 7 to 10 days if inflammation is severe
Follow-up schedule: Follow-up visits are scheduled for Day 1, Week 1, 1 Month, 3 Months, 6 Months, and then every 6 months after surgery. Intraocular pressure should be checked at each visit to detect glaucoma early.

4. Optical and Visual Rehabilitation

After surgery, the child is aphakic, or without a natural lens, unless an IOL is implanted.
Options:

Glasses: for bilateral cases
Contact lenses: preferred for unilateral cases, as they provide better visual quality
Bifocal or progressive lenses: after walking age

Amblyopia therapy (patching):

For unilateral cataract: patch the healthy eye for several hours daily.
For bilateral cataracts: alternate patching daily
Treatment continues for several years and is adjusted according to improvements in visual acuity.

Possible Complications

Even with meticulous surgery, complications may occur:

Inflammation and fibrotic membrane formation
Secondary cataract (posterior capsule opacification) within 6 months
Glaucoma: may develop years later, requiring lifelong follow-up.
IOL decentration or dislocation
Retinal detachment
Corneal dystrophy (rare, associated with anterior chamber IOLs)
Endophthalmitis (extremely rare but vision-threatening)

Visual Prognosis and Long-Term Outlook

Final visual outcomes depend on:

Age at diagnosis
Timing of surgery
Whether one or both eyes are affected
Associated eye malformations
Adherence to amblyopia treatment
Parental commitment to follow-up

With early detection and appropriate treatment, many children achieve functional binocular vision, attend regular school, and lead normal lives.
However, lifelong monitoring is necessary because complications such as glaucoma or retinal detachment may develop years later.

Prevention and Early Detection

Prenatal care: vaccinate against rubella and screen for infections
Newborn screening: perform red reflex examination before hospital discharge
Parental awareness: seek early consultation if your baby’s eye appears white or does not follow faces
Genetic counseling: recommended for families with a history of hereditary cataracts

Asked Questions (FAQ)

1. Can congenital cataracts be prevented?
Not all congenital cataracts can be prevented, but many are avoidable through maternal vaccination, infection control, and genetic counseling.

2. Does every congenital cataract require surgery?
No. Small, peripheral opacities that do not obstruct the visual axis can be monitored without the need for surgery.

3. Will my child need glasses after surgery?
Yes. Even with IOL implantation, most children require glasses or contact lenses to optimize vision and support binocular function.

4. Is congenital cataract surgery safe?
In the hands of experienced professionals, the procedure is safe. However, careful follow-up is crucial to effectively manage inflammation and detect glaucoma at an early stage.

5. Can vision return to normal?
If treated within the critical window (first 6 to 10 weeks), vision can develop almost normally. Delayed treatment significantly reduces the chances of full recovery.

Key Takeaways

Congenital cataract is a highly treatable cause of childhood blindness, but only with early diagnosis and timely surgery.
Genetic and infectious factors are leading causes; therefore, prevention should begin before birth.
Surgery before two months of age, combined with consistent amblyopia therapy, provides the best outcomes.
Long-term follow-up is essential to monitor for complications such as glaucoma or secondary cataracts
.