Leucocoria: what is it, causes, symptoms, treatment, prognosis

What is Leukocoria?

Leucocoria means a white retinal reflex or a white "glow" of the pupil, the condition is also often called "cat's eye". Leukocoria is a symptom manifested by an abnormal pupillary reflex, more clearly visible in mydriasis or photograph. This is often the first sign of a series of serious intraocular disorders. Leukocoria is usually observed with congenital cataract, Coates disease, retinoblastoma, retinopathy of prematurity, toxocariasis, Norrie's disease, retrolental fibroplasia and other diseases. Immediate diagnosis and treatment is imperative, as most conditions are vision-threatening and retinoblastoma can be life-threatening. Immediate referral to an ophthalmologist, interdisciplinary interaction with a pediatric ophthalmologist, retinal specialist, and ophthalmic oncologist will help in treating leukocoria-laden eyes appropriately.

How is leukocoria detected?

In more obvious cases, a white pupil can be detected simply by chance observation. In other situations, the pupil may appear white only under certain circumstances, such as when the pupil becomes larger in a darkened room or when a child looks in a certain direction. Sometimes leukocoria is found in flash photography when one pupil has an abnormal or "white reflex" compared to the other eye, which has a normal "red reflex". Finally, a pediatrician can detect leukocoria, especially when looking into the eyes with an ophthalmoscope.

Causes and risk factors

The normal red reflex of the human eye is due to the retro-luminescence of the normal vasculature. choroid (choroid), reflected through the retina, vitreous humor, lens, pupil and cornea. Any interference with any of these structures will lead to a change in the red reflex or leukocoria. Some of the common causes of leukocoria are:

• Retinoblastoma;
• Coates disease (exudative retinitis or retinal telangiectasia);
• Persistent hyperplastic vitreous;
• Retinopathy of prematurity;
• Ophthalmic toxocariasis and toxoplasmosis;
• Astrocytic hamartoma;
• Familial exudative vitreoretinopathy (SEVRP);
• Vitreous hemorrhage;
• Retinochoroidal coloboma;
• Endogenous endophthalmitis;
• Pigment incontinence (Bloch-Sulzberger syndrome);
• Retinal disinsertion;
• Child uveitis;
• Myelinated retinal nerve fibers;
• Medulloepithelioma;
• TORCH syndrome (toxoplasmosis, other pathogens, rubella, cytomegalovirus and herpes simplex).

What is a red reflex?

When light enters the eye through the pupil, the retina absorbs most of the light. However, a small amount of light is reflected by the retina from the eye through the pupil. The light is reddish orange in color, reflecting the color of the normal retina. The red reflex is easiest to see when the observer's line of sight is aligned with the light source in the eye. An example would be a camera in which the flash is mounted very close to the lens, resulting in photographs with red pupillary reflexes.

The red reflex is either absent or white with leukocoria. This occurs as a result of improper reflection of light coming from the eye.

Epidemiology

In a retrospective 10-year study, the average age of children with leukocoria was 42.5 months. Bilateral lesion was observed in 54% with a sex ratio between men and women of 1: 5. 76% of children were under the age of six. 75% of cases were caused by cataractand 21% with retinoblastoma. Other causes of leukocoria included retinal detachment (1%), retinopathy of prematurity (1%), residual membrane of the pupil (1%), primary persistent hyperplastic vitreous humor (0.6%), endophthalmitis (0.64%), optic coloboma (0.3%), iris heterochromia (0.3%) and ametropia (0.3%).

Data from the Third National Cancer Survey show that there are 11 new cases of retinoblastoma per million children under 5 years of age each year. Retinoblastoma is the most common intraocular malignant neoplasm in children and accounts for 2% of all cancers in children. The estimated incidence ranges from 3 to 42 per million live births. In America, the incidence is 12 per million live births in children under the age of five, with a prevalence of 6% of all cancers in this age group. Retinoblastoma affects both sexes equally. Retinoblastoma is most common in children under four years of age. The incidence of Coates disease is 0.09 per 100,000 population, with 85% of cases affecting men.

The global prevalence of cataracts in children ranges from 0.3% to 23% per 10,000, with a mean of 1 in 10,000 and 0.6 to 9.8% per 10,000 for congenital cataracts with a mean of 1.7 in 10,000 based on many studies that have reported congenital cataract. In a study of 602 newborns, the incidence of retinopathy of prematurity (ROP) at any stage was 34%, and the prethreshold ROP of type 1 was 5% with an average gestational age of 31 weeks. The incidence of neonatal endophthalmitis in the United States alone is 4.2 per 1,000,000 live births.

Diagnostics

The physician needs to take a detailed medical history of the present illness, past ocular history, and family history. Family photos can help you know if leukocoria was present from birth or later in childhood. Persistent hyperplastic vitreous is most often present at birth. Presence in anamnesis premature allows doctors to conduct research in accordance with retinopathy of prematurity, which manifests itself as leukocoria due to retinal detachment and retrolental fibroplasia. Birth trauma can lead to hypheme or vitreous hemorrhage, which manifests as an altered pupillary reflex. A family history is important in retinoblastoma, EVERP, and coloboma.

Pupillary reflex color also provides clues to the diagnosis. Retinoblastoma presents with a whitish pupillary reflex, while congenital cataracts exhibit a blue-gray reflex. With Coates disease and retinal detachment, a yellowish reflex appears. In 20% of cases, retinoblastoma manifests itself squint. Retinal detachment, vitreous hemorrhage, Coates disease, and retinoblastoma (60%) usually present as unilateral disease, while EVERP, endogenous endophthalmitis, astrocytic hamartomas and 40% retinoblastomas are bilateral.

Also, any child with leukocoria should be examined for vision, pupillary reflexes, examination of the anterior segment and fundus using slit lamp, indirect ophthalmoscopy, fluorescence angiography, optical coherence tomography of the retina (OCT) and ultrasound scanning in B-mode. Neuroimaging, blood tests, genetic testing, and fine needle aspiration cytology are other complementary tests done to confirm the diagnosis.

Treatment

Leukocoria is a symptom of an underlying eye disease. Treatment for leukocoria includes treating the underlying condition (retinoblastoma, cataract, retinal detachment, Coates disease, EVERP, infection, etc.) responsible for the appearance of the white retinal reflex.

Forecast

Retinoblastoma has a 90% to 95% survival rate with a good prognosis, although the affected eye may lose sight. Poor prognostic signs of retinoblastoma are optic nerve invasion / extrascleral / uveal invasion, multifocal tumors, late diagnosis, and grade of differentiation. Bilateral lesion does not worsen the prognosis, and the degree of necrosis and calcification does not affect the prognosis. The prognosis of retinoblastoma depends on the condition of the tumor - the worst eye. Signs of a high risk of recurrence are optic nerve invasion, massive damage to the choroid, orbit, anterior segment, and uveal tissue.

Congenital cataracts have a good prognosis if diagnosed early and operated on for up to six weeks. The prognosis of acquired cataracts is better than that of congenital cataracts. Bilateral cataracts have a better prognosis than unilateral ones. Even slight turbidity can cause significant amblyopia. Unilateral cataracts also increase the risk of anisometropia.

Endogenous endophthalmitis does not have a favorable prognosis. Most cases result in retinal detachment and uncontrolled infection, ultimately requiring enucleation or evisceration.

Familial exudative vitreoretinopathy (EVERP) is a lifelong condition that can recur at any time. After treatment, patients with EVERP should have a fundus examination and fluorescence angiography every six months. The prognosis for retinal detachment surgery is very poor because children often have low visual acuity with a higher percentage of macular lesions. In addition, the child has a lifelong risk of cataracts, glaucoma and recurrence of retinal detachment.

Medulloepithelioma confined to the eye has an excellent prognosis with a 5-year survival rate of 90-95% after enucleation.

The prognosis for retinochoroidal coloboma is good enough if amblyopia is treated in time and preventive laser therapy is carried out to prevent retinal detachment. Involvement of foveal tissue in a coloboma results in severe vision loss.

Complications

Retinoblastoma:

• Choroidal and scleral invasion;
• Metastases;
• Vitreous sowing;
• Tumor invasion into the anterior chamber;
• Iridic rubeosis and glaucoma;
• Relapse of the tumor and subsequent neoplasms;
• Increased intracranial pressure;
• Tuberculosis;
• Death.

Childhood uveitis:

• Amblyopia;
• Cataract;
• Tape keratopathy;
• Glaucoma;
• Cystic macular edema.

Retinochoroidal coloboma:

• Cataract;
• Retinal disinsertion;
• Amblyopia;
• Weakness of zonular support of the lens.

Cataract and its surgery:

• Amblyopia;
• Anisometropia;
• Secondary capsular opacification;
• Secondary glaucoma;
• Postoperative uveitis and endophthalmitis;
• Retinal disinsertion.

Coates disease:

• Neovascular glaucoma;
• Orbital cellulite;
• Anterior chamber cholesterol;
• Vitreous hemorrhage;
• Neovascularization of the disc and retina;
• Intraretinal microcysts;
• Secondary vasoproliferative tumor.