Leukocoria

Leukocoria may sound unfamiliar, but its appearance is often easy to spot. It shows up as a white or pale reflection in the pupil instead of the normal red reflex you see in photos or during an eye exam. Leukocoria can signal serious eye conditions such as retinoblastoma, congenital cataracts, or other pediatric eye diseases that need quick medical attention.

This symptom does not always point to the same cause, which makes it important to understand the range of conditions linked to it. In children, it may be the first sign of problems like retinopathy of prematurity, Coats disease, or inherited disorders. In some cases, non-disease factors can also cause it, but ruling out dangerous causes is always a priority.

Definition of Symptom

Leukocoria means “white pupil.” It describes an abnormal white or gray reflection seen in the pupil when light enters the eye. Instead of the normal red reflex, the pupil may appear white in photographs or during an eye exam. This symptom happens when light reflects differently from the structures inside the eye.

The reflection often comes from the retina or other tissues that are not normally visible. Doctors often notice leukocoria during a routine red reflex test, while parents may first see it in flash photos. In these images, one eye may show a white glow while the other shows the expected red reflex.

Key Points About Leukocoria

• It is a symptom, not a disease.
• It signals an underlying problem in the eye.
• It may affect one or both eyes.

Term	Meaning
Leukocoria	White reflection in the pupil.
Red Reflex	Normal reddish glow of retina.
White Pupil	Common description of leukocoria.

A white pupil can result from several eye conditions. These include congenital cataracts, retinal disorders, or tumors such as retinoblastoma. Because of these possibilities, doctors take leukocoria seriously.

Possible Causes/Diseases Condition

Several eye conditions, some minor and some very serious, can cause leukocoria. It often means that light is reflecting from abnormal tissue inside the eye instead of the healthy retina.

• Retinoblastoma is one of the most critical causes. This rare childhood eye cancer often first appears as a white pupil and needs urgent evaluation.
• Congenital cataracts can also create a white reflex. These lens cloudings may block normal light passage and affect vision development if not treated early.
• Persistent Fetal Vasculature (PFV) happens when blood vessels in the eye do not regress after birth. This can lead to a white pupil and reduced vision.
• Coats’ disease causes abnormal blood vessel growth in the retina. Leaking vessels can cause retinal detachment and leukocoria, most often in young males.
• Retinopathy of prematurity affects premature infants. Abnormal blood vessel growth in the retina may lead to scarring, detachment, and a white reflex.
• Ocular toxocariasis, caused by a parasitic infection, can produce retinal lumps that appear as leukocoria.
• Norrie disease, a rare genetic condition, leads to abnormal retinal development in infants and can cause blindness along with a white pupil.

Other possible causes include retinal detachment, severe eye infection, and advanced cataracts later in life.

Condition	Key Feature
Retinoblastoma	Childhood eye cancer
Cataract	Clouded lens
PFV	Persistent fetal vessels
Coats’ disease	Abnormal retinal vessels
Retinopathy of prematurity	Preterm retinal changes
Ocular toxocariasis	Parasitic infection
Norrie disease	Genetic disorder

Other Non-Disease Causes

Not all cases of leukocoria come from eye diseases. Sometimes the white reflex appears because of outside factors or normal variations in the eye. One common cause is camera flash. In certain lighting, the angle of a flash can reflect off the retina in a way that looks white instead of red. This effect may show up in only one eye depending on head position.

Unequal pupil size or natural differences in eye shape can also create a misleading reflection. These differences may make one eye appear to have a white reflex when no underlying disorder is present. In rare cases, scarring from past eye injury or surgery can cause light to reflect differently. The scar tissue may scatter light, creating a pale or whitish appearance in the pupil.

Some children with a history of premature birth may show a white reflex without active disease. For example, those screened for retinopathy of prematurity (ROP) may later have changes in the eye that mimic leukocoria but are not linked to ongoing disease. A quick reference table:

Cause	Description	Disease-Related?
Camera flash	Light reflection artifact	No
Unequal pupil size	Normal variation in anatomy	No
Eye injury scarring	Old trauma altering light reflection	No
Premature birth history	Non-active changes after ROP screening	No

These non-disease causes show that not every white reflex signals a serious eye condition, though medical evaluation remains important.

How It Causes the Symptom

Leukocoria appears when the normal red reflex gets blocked or replaced by light reflecting from abnormal tissue inside the eye. In a healthy eye, light passes through a clear lens and reflects as red from the retina. When disease or structural changes interfere, the pupil may look white, yellow, or gray instead. Common causes include:

• Retinoblastoma: A tumor that reflects white instead of red.
• Congenital Cataract: A cloudy lens that blocks the red reflex.
• Coats Disease: Abnormal retinal vessels causing fluid buildup.
• Retinal Detachment: Aeparation of the retina altering light reflection.

Doctors use an ophthalmoscope to check the reflex directly. If the reflex is absent or abnormal, it signals an issue preventing normal light travel inside the eye. This test often provides the first clear sign of a hidden disorder.

The mechanism varies by condition. For example, cataracts scatter light before it reaches the retina. Retinoblastoma creates a solid mass that reflects white. Retinal detachment stops the retina from reflecting properly, while changes in Coats disease create irregular reflections.

In all cases, the symptom happens because something interrupts the usual pathway of light. Instead of a uniform red glow, the pupil shows a pale or opaque reflection that can be seen in photos or during an eye exam.

Possible Complications

Leukocoria can lead to vision loss if the underlying cause is not treated quickly. Conditions like congenital cataracts or retinoblastoma may block normal visual development and result in permanent impairment. Some causes, such as retinoblastoma, carry risks beyond vision. If untreated, this eye cancer can spread outside the eye and become life-threatening.

Children with leukocoria may also face amblyopia (lazy eye). When one eye does not receive clear visual input, the brain may favor the other eye, leading to poor visual development. Other possible complications include:

• Strabismus (crossed eyes) due to unequal vision
• Glaucoma from abnormal eye pressure
• Retinal detachment in conditions like Coats’ disease

Condition	Possible Complication
Congenital cataract	Permanent vision loss
Retinoblastoma	Spread of cancer, vision loss
Coats disease	Retinal detachment, blindness
Retinopathy of prematurity	Scarring, retinal detachment

When to Seek Medical Attention

Leukocoria should never be ignored. A white or yellow reflection in the pupil can signal an underlying eye disease. Parents often notice this first in photographs or under certain lighting conditions, and should act quickly. Seek an eye exam right away if you notice:

• A white, gray, or yellow pupil.
• A difference in pupil color between the two eyes.
• Poor or reduced vision.
• Eyes that do not look in the same direction.
• Unusual eye movements.

An eye doctor can perform a full evaluation. A detailed eye exam can find out whether the cause is a cataract, a problem with the retina, or another condition that needs treatment. Adults who see a white reflection in their own eyes should also contact an eye doctor right away.

While leukocoria is more common in children, it can appear in adults and may signal a serious problem. If unsure, it is safest to schedule an appointment rather than wait. A simple check by an eye doctor can find the cause and guide the next steps.