Congenital Cataract

Some children are born with conditions that affect the structure of the eye. These are called congenital eye abnormalities, meaning they are present at or shortly after birth. They can have many different causes—including genetic changes, infections during pregnancy, metabolic conditions, or unknown reasons. These conditions range widely in severity. Some require only monitoring, while others need prompt treatment to protect a child’s vision.

A congenital cataract is a clouding of the lens of the eye that is present at birth or appears in the weeks shortly after. The lens is the clear part of the eye that sits behind the colored iris and helps focus light onto the back of the eye. When a cataract forms, the lens becomes cloudy and blocks or scatters light, making vision blurry or unclear. A congenital cataract may affect one eye (called unilateral) or both eyes (called bilateral). Because there are many possible shapes, sizes, and causes, congenital cataract is considered a group of related conditions rather than a single disease.

Congenital cataracts are a leading treatable cause of childhood blindness worldwide. They are responsible for an estimated 5–20% of blindness in children. Around 20,000 to 40,000 children are born with this condition each year globally, and roughly 3 to 6 out of every 10,000 babies are affected. The clouding of the lens itself does not always worsen over time. However, if a significant cataract is left untreated, the brain stops learning to use the affected eye. This leads to a permanent form of vision loss called amblyopia (lazy eye) that cannot be fully corrected later in life. With early diagnosis and timely surgery, most children can achieve good vision outcomes.

Congenital cataracts develop when the normal growth of the lens is disrupted before or shortly after birth. The cause can be genetic, related to an infection or illness during pregnancy, connected to another health condition, or unknown. In roughly one-third of cases, no specific cause is found.

Hereditary (genetic) causes are the most common identifiable source and account for roughly one-quarter to one-third of all congenital cataracts. Many of these are passed down in an autosomal dominant pattern, meaning a child only needs to inherit the gene change from one parent for the condition to develop. Gene mutations affecting proteins in the lens—such as the crystallin proteins that keep the lens clear—are a common genetic mechanism.

Other known causes include:

• Infections during pregnancy: Viruses and other infections contracted by the mother can cross to the developing baby and affect the eye. These include rubella (German measles), cytomegalovirus (CMV), toxoplasmosis, and herpes simplex virus. Together, these are sometimes called TORCH infections.
• Metabolic conditions in the baby: These disorders affect how the body processes certain substances that can damage the lens. Galactosemia (a condition where the body cannot break down a sugar called galactose) and hypoglycemia (low blood sugar) are examples.
• Chromosomal conditions: Certain genetic syndromes can affect the number or structure of chromosomes associated with congenital cataracts. Down syndrome (trisomy 21) is the most well-known example.
• Other eye abnormalities: Congenital cataracts sometimes occur alongside other structural problems in the eye, such as PFV or aniridia (absent or incomplete iris).
• Unknown cause (idiopathic): In many cases, especially unilateral cataracts, a clear cause cannot be identified despite thorough testing.

Congenital cataracts can occur in any family, including those with no prior history of eye conditions. However, certain factors increase the likelihood that a child will be born with or develop a cataract shortly after birth.

• Family history: Having a parent or sibling with congenital cataract raises the risk, especially for the inherited lamellar type.
• Chromosomal conditions: Babies born with Down syndrome or other chromosomal disorders have a higher rate of congenital cataract.
• Maternal infection during pregnancy: A mother who contracts rubella, CMV, toxoplasmosis, or herpes during pregnancy is at greater risk of having a baby with a cataract.
• Metabolic conditions in the newborn: Galactosemia and other metabolic disorders identified through newborn screening are linked to lens clouding.
• Premature birth: Babies born significantly early (premature) may face higher rates of eye abnormalities, including cataracts.
• Other congenital eye abnormalities: The presence of other structural eye problems, such as PFV or aniridia, increases the chance that a cataract is also present.

Screening for congenital cataract begins in the newborn nursery. Pediatricians and neonatologists perform a red reflex test shortly after birth. In this test, the doctor shines a light into the baby’s eyes and looks for a bright reddish-orange glow—like the red-eye effect in a photograph. A normal red reflex means light is passing through the lens clearly. An absent, white, or asymmetrical reflex may signal a cataract or another eye problem and should prompt urgent referral to a pediatric ophthalmologist (an eye doctor who specializes in children). The red reflex test is also repeated at all routine well-child checkups through early childhood. Children with a known genetic risk, a family history of congenital cataract, or a related medical diagnosis should be referred for a full dilated eye exam early in infancy.

Congenital cataracts caused by genetic mutations cannot be prevented. However, genetic counseling is available for families with a known history of hereditary cataract. A genetic counselor can explain the inheritance pattern, estimate the likelihood of the condition occurring in future pregnancies, and guide decisions about genetic testing. Some infectious causes can be reduced through prevention. Pregnant women can lower the risk of TORCH infections by washing hands frequently, avoiding undercooked meat, staying away from cat litter (a source of toxoplasmosis), and making sure their rubella vaccination is up to date before becoming pregnant.

Unlike adults who can describe blurry vision, infants and young children cannot communicate what they see. This makes early detection dependent on physical signs that parents, caregivers, and doctors can observe. The most important warning sign is a white, gray, or absent red reflex in one or both eyes.

Signs that may indicate a congenital cataract include:

• White or cloudy pupil (leukocoria): The dark center of the eye looks white or hazy, especially visible in photos taken with a flash.
• Absent or abnormal red reflex: The reddish-orange glow in the eye is missing or looks uneven compared to the other eye.
• Wandering or roving eye movements (nystagmus): The eye moves back and forth involuntarily. This can be a sign that the eye is not receiving clear images.
• Eyes that do not line up (strabismus): One eye turns in, out, up, or down instead of moving in coordination with the other eye.
• Poor visual tracking: The baby does not follow moving objects or faces with their eyes as expected for their age.
• Squinting or holding objects very close: The child strains to see clearly.
• Sensitivity to bright light (photophobia): The child squints or turns away from lights more than expected.
• A lazy eye (amblyopia): If a cataract is not found early, one eye may stop developing normally. The brain begins to rely on the clearer eye and essentially ignores the other.

A pediatric ophthalmologist diagnoses congenital cataract through a full eye examination. Because infants and young children cannot cooperate with standard vision tests, the exam includes several specialized tools and techniques. Early diagnosis is critical—delays of even a few weeks can affect visual development in young infants. When a cataract is found, the doctor will also order tests to look for an underlying cause.

• Red reflex test: This test is performed by a pediatrician or neonatologist using a handheld ophthalmoscope. It is the first-line screening tool and can detect significant lens opacities in newborns and infants.
• Slit-lamp examination: A specialized microscope shines a narrow beam of light through the eye so the doctor can see the lens in detail. This confirms the presence, location, and size of the cataract.
• Dilated fundus exam: Eye drops are used to widen (dilate) the pupil. The doctor then examines the back of the eye to check for other abnormalities such as PFV or retinal problems.
• B-scan ultrasound: If the cataract is dense and blocks the view of the back of the eye, sound waves are used to image the internal structures without light.
• Refraction assessment: This test measures the optical power of the eye to guide surgery planning and determine the correct prescription for glasses or contact lenses after treatment.
• Blood and urine tests: Newborn metabolic screening may already flag galactosemia. Additional blood or urine testing can look for metabolic and infectious causes.
• Genetic testing: If a hereditary cause is suspected, genetic testing of the child and sometimes the parents can identify the specific mutation involved.
• TORCH serology: This is a blood test panel that checks for antibodies to rubella, CMV, toxoplasmosis, and herpes—the infections most commonly linked to congenital cataract.

Congenital cataract is not curable in the sense that the clouded lens cannot be cleared with medicine or eye drops. The primary treatment is surgery to remove the affected lens. However, surgery alone is not enough. After the natural lens is removed, your child will need both an optical correction—glasses, contact lenses, or an artificial lens implant—and vision therapy to help the brain learn to use the treated eye. The timing of treatment, the type of lens correction used, and the intensity of follow-up care all affect how well your child’s vision develops.

Surgery to remove the cataract (called lensectomy or lens aspiration) is typically performed under general anesthesia in infants and young children. Your surgeon removes the cloudy lens and, in most cases, also removes the clear membrane at the back of the lens (the posterior capsule) to prevent it from becoming cloudy after surgery—a complication that occurs very commonly in young children if the capsule is left in place. For infants under six months of age, the natural lens is removed but an artificial lens implant (intraocular lens—IOL) may not be placed right away. Instead, a contact lens or glasses are used to correct vision. For older children, an IOL is often implanted at the time of surgery, though glasses may still be needed afterward. The right approach depends on your child’s age, the type of cataract, and whether one or both eyes are affected.

After surgery, your child will need to wear a patch over the stronger eye for part of each day. This is called occlusion therapy or patching. It forces the brain to use the treated eye and is one of the most important parts of treatment for preventing amblyopia. Patching must be done consistently for months or years. Your child will also need frequent follow-up visits with the ophthalmologist, as glasses or contact lens prescriptions change rapidly during early childhood as the eye grows. Possible complications after surgery include glaucoma (increased pressure inside the eye), re-clouding of the lens capsule, and continued amblyopia if patching is not done as directed. Lifelong monitoring of eye health and vision is recommended for all children treated for congenital cataract.

Caring for a child with congenital cataract takes dedication, patience, and a strong partnership with your medical team. The early months and years of treatment—surgery, contact lenses or glasses, patching—can feel demanding. But the effort made during this critical window of visual development has a lasting impact on your child’s sight and quality of life. Many children treated early go on to develop functional vision that allows them to read, play, attend school, and participate fully in daily activities. Connecting with other families through support groups and staying in close communication with your child’s ophthalmologist will help you navigate this journey with confidence.

To further your understanding of your child’s diagnosis and to contribute to cutting-edge research, consider participating in a clinical trial so clinicians and scientists can learn more about causes, symptoms, treatment, and prevention of congenital cataract and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

To learn more about clinical trials and find studies that may be right for your child, visit NIH Clinical Research Trials and You at www.nih.gov/health-information/nih-clinical-research-trials-you and ClinicalTrials.gov to search active studies by condition, location, and age group.