Leukocoria is an abnormal white reflection in the pupil of the eye, replacing the familiar red-eye glow you’d normally see in flash photographs. It signals that something inside the eye is blocking or reflecting light abnormally, and it’s one of the most important early warning signs of serious eye conditions in children. About 76% of children who present with leukocoria are under six years old.
Why the Pupil Looks White
In a healthy eye, light passes through the pupil, hits the blood-rich retina at the back of the eye, and bounces back out as a reddish glow. That’s the “red reflex” you see in flash photos. When something sits between the pupil and the retina, or when the retina itself is abnormal, that light reflects back as white, gray, or yellowish instead of red. The color of the abnormal reflex can hint at the underlying cause: a bright white reflection is typical of retinoblastoma (a childhood eye cancer), a blue-gray pupil is commonly seen with congenital cataracts, and a yellowish reflex suggests advanced Coats disease, where fluid and fatty deposits have accumulated beneath the retina.
Most Common Causes
In a ten-year study of children presenting with leukocoria, cataracts accounted for 75% of cases and retinoblastoma accounted for 21%. Everything else combined made up roughly 4%, including retinal detachment, retinopathy of prematurity, a persistent membrane across the pupil, and a developmental abnormality called persistent hyperplastic primary vitreous. About 54% of children in that study had both eyes affected, and boys were 1.5 times more likely to be diagnosed than girls.
Congenital Cataracts
A cataract is a clouding of the lens inside the eye. When a baby is born with one, or develops one in early childhood, the clouded lens blocks the normal light path and produces that characteristic blue-gray or whitish pupil. Some congenital cataracts are small enough that they don’t immediately affect vision, while others are dense enough to be visible to parents without any special equipment. The earlier a visually significant cataract is treated, the better the chance of normal visual development, because a child’s brain is still learning to process visual input during the first years of life.
Retinoblastoma
Retinoblastoma is a cancer of the retina that almost exclusively affects young children. Globally, about 6,275 new cases were diagnosed in 2021, up from roughly 4,674 in 1990. Leukocoria is often the very first sign parents notice, typically as a white glow in one eye in photographs. About 60% of cases affect only one eye; the rest are bilateral. Survival rates are high when it’s caught early, but delayed diagnosis can allow the cancer to spread beyond the eye.
Coats Disease
Coats disease is a non-hereditary condition where abnormal blood vessels in the retina leak fluid and fatty deposits. It overwhelmingly affects boys, with one large study of 351 consecutive cases finding 84% were male, and it’s virtually always limited to one eye. Most cases are diagnosed in the first or second decade of life. Parents may notice the child’s eye drifting (strabismus), a yellowish pupil reflex, or vision loss. The hallmark features are an accumulation of fluid beneath the retina, irregularly widened blood vessels, and areas of poor blood flow at the edges of the retina.
Less Common Causes
Persistent hyperplastic primary vitreous (PHPV) is a developmental condition where fetal blood vessels inside the eye fail to dissolve before birth, as they normally do around the 20th week of pregnancy. The leftover tissue sits behind the lens and produces a white reflex, often alongside a noticeably smaller eye and cataract formation. It’s usually present at birth.
Ocular toxocariasis is an infection caused by ingesting eggs of the Toxocara parasite, most commonly from contaminated soil. The larvae travel through the bloodstream and can settle in the eye, forming a white or yellowish mass on the retina. Children between ages 2 and 9 are most commonly affected. Parents typically notice a white pupil, eye redness, or the eye turning inward or outward before the child complains of any symptoms.
How Leukocoria Is Detected
Pediatricians screen for leukocoria using a red reflex test, sometimes called the Brückner test. The doctor holds an ophthalmoscope about one to two feet away in a dimly lit room and shines light into both of the child’s eyes simultaneously. A healthy eye produces an even, symmetric reddish glow. Any white, dull, or asymmetric reflection is flagged as abnormal. The doctor then moves closer to check each eye individually.
Many parents first spot leukocoria in casual flash photographs, a phenomenon called photoleukocoria. Smartphones can capture a white pupil when the flash aligns with the camera lens, the child’s pupils are undilated, and the child is looking slightly toward the nose. This has led to earlier detection in some cases. However, smartphones also produce a significant number of false positives. Different camera angles, lighting conditions, and even the specific phone model can create a white reflex in a perfectly healthy eye. A white glow in a photograph is worth investigating, but only an eye exam by an ophthalmologist can confirm or rule out a true problem.
Why Urgent Evaluation Matters
The American Academy of Pediatrics recommends that any child with an abnormal red reflex be referred to a pediatric ophthalmologist, and that suspected leukocoria specifically warrants urgent referral. The reason is straightforward: the conditions behind a white pupil range from vision-threatening to life-threatening, and nearly all of them have better outcomes when caught early. Retinoblastoma, for example, is highly curable when confined to the eye but far more dangerous once it spreads. Congenital cataracts treated in the first weeks of life give the brain the best chance to develop normal sight in that eye. Even Coats disease, which isn’t cancerous, can lead to permanent vision loss or a painful, blind eye if fluid buildup goes untreated for too long.
If you notice a persistent white, yellowish, or asymmetric glow in your child’s eye, whether in photos or just under certain lighting, getting it checked promptly is the single most important step. The exam itself is quick and painless, and a normal result simply means peace of mind.