Leukocoria is a disorder where the circular hole (pupil) in the colored eye area is white. It's created by an abnormal reflection from the light-sensitive layer at the back of the eye (the retina). The retina absorbs most of the light that reaches the eye through the pupil. However, a small portion of the light is reflected by the retina and exits the eye through the pupil. The reflected light is called the red reflex and is usually reddish-orange, mirroring the retina's normal color.
The red reflex is seen most readily when the observer's line of sight is in alignment with the light source; for example, a camera with the flash is mounted next to the lens. In leukocoria, the red reflex is either absent or a white, yellow, pale, or otherwise abnormal light reflection seen in the pupil of one or both eyes. Often, the phenomenon is the initial sign of a range of underlying serious eye diseases. Some of the conditions may pose a serious threat to vision, while others can be life-threatening. Therefore, it's advisable to seek prompt evaluation of leukocoria by an ophthalmologist.
Also Known As
- White pupil
- Cat's eye pupil
- White pupillary reflex
Causes & Risk Factors
The white reflex may be triggered by any condition that affects the transmission of ambient light and the light's reflection through the pupil. The most common causes include:
- Coats disease
- Pediatric uveitis
- Congenital cataract
- Retinal detachment
- Vitreous hemorrhage
- Astrocytic hamartoma
- Retinochoroidal coloboma
- Bloch-Sulzberger syndrome
- Persistent fetal vasculature
- Retinopathy of prematurity
- Endogenous endophthalmitis
- Medullated retinal nerve fiber
- Familial exudative vitreoretinopathy
- Ocular toxocariasis and toxoplasmosis
- TORCH syndrome (Toxoplasmosis, Other agents, Rubella, Cytomegalovirus, and Herpes simplex syndrome)
Often, leukokoria in a child indicates retinoblastoma, which is also its most severe cause. Over 50 percent of retinoblastomas are suspected or diagnosed in the USA after a white reflex is spotted, usually by a close relative. The most significant risk factor is a family history of hereditary causes.
Signs & Symptoms
In obvious leukocoria cases, the pupil seems white on casual observation. In other cases, the pupil may look white only in certain situations, like when the pupil widens in a darkened room. At times, the white reflex is detected from photographs where one pupil has a normal red reflex, while the other eye shows an abnormal reflex.
The patient needs to receive a thorough workup for leukocoria. The ophthalmologist will take a present illness medical history, previous ocular history, medical history, and family history of a child presenting with leukocoria. In the case of an infant or toddler, s/he will take a detailed birth and delivery history. S/he will examine the patient for vision and pupillary reflexes and perform various exams, including:
- Direct ophthalmoscopy
- Indirect ophthalmoscopy
- Retinal fundus photography
- Fundus fluorescein angiography
- Slit-lamp examination of both anterior segment and fundus
S/he may order additional tests to confirm the diagnosis, including:
- Blood workup
- Genetic testing
- Fine-needle aspiration cytology
- Orbital/head imaging studies, such as B-scan ultrasonography, MRI of the head and orbits, and Optical coherence tomography (OCT) of the retina
The treatment of leukocoria varies and depends on the underlying condition. The doctor may recommend observation, medication, surgery, chemotherapy, and radiation. For example, the primary mode of treatment for intraocular retinoblastoma is chemo reduction accompanied by adjuvant consolidative treatment, i.e., laser photocoagulation, thermotherapy, cryotherapy, and chemotherapy. The doctor may recommend observing minor cases of Coats disease, persistent fetal vasculature and retinopathy of prematurity. Congenital cataracts and retinal detachment may require surgical intervention.
Prognosis & Long-Term outlook
Early diagnosis and treatment can improve the child's chances of maintaining their vision. Retinoblastoma has a 90 to 95 percent survival rate with a good prognosis, but the involved eye may be visually impaired.
Congenital cataracts have a good prognosis if detected early and operated on within six weeks.
Endogenous endophthalmitis has a poor prognosis, while familial exudative vitreoretinopathy is a lifelong disease that may reactivate at any time.
Prevention & Follow Up
Leukocoria is not preventable. Parents and siblings should all be involved in care management. The doctor will chart a plan for proper follow up based on the underlying disease.