A 'Gleam' in the Left Eye of a 5-Year-Old Boy

Mauricio E. Pons, MD; Maria Silvana Horenstein, MD


July 22, 2016


Coats disease is a rare idiopathic retinal condition, first described by George Coats in 1908, in which abnormal telangiectatic retinal vessels cause intra- and subretinal exudates, leading to serous retinal detachment.[1] The most common presentations are decreased visual acuity, strabismus, or leukocoria, which is generally more yellow than white owing to the presence of subretinal lipid. Most cases that present with leukocoria are diagnosed at age 5-9 years, which is older than most patients with retinoblastoma.

No racial or laterality predilection is noted for Coats disease. The incidence and prevalence are unknown.

Clinical examination typically reveals subretinal lipid and abnormal telangiectatic vessels. In advanced cases, ocular ultrasonography demonstrates complete retinal detachment with massive subretinal lipid. Intraocular calcification is very rarely present in Coats disease, another feature that helps to distinguish it from retinoblastoma.

Coats disease is presumed to have a vascular etiology, postulated to be a somatic mutation in the NDP gene, resulting in a deficiency of norrin (the protein product of the NDP gene) within the developing retina. It is unilateral in 95% of children, with a 4-to-1 male predominance and a bimodal distribution in males younger than 18 years and middle-aged men, often as a secondary response to a vascular event.

The mean age at diagnosis is 5 years. It may be seen as early as age 1 month, and most cases are diagnosed before 10 years of age. The condition is more severe in younger patients (especially those < 3 years), in whom the disease progresses more rapidly.

Coats disease has a sporadic occurrence and is not known to be associated with other organ abnormalities, ocular conditions, or systemic conditions. No evidence suggests genetic predisposition; however, it has been associated with retinitis pigmentosa, muscular dystrophy, deafness, and Norrie disease.[2]

Clinically, Coats disease presents with decreased vision, strabismus, leukocoria (white pupillary reflex or "cat's eye reflex"), and redness. It may, however, be detected incidentally.[3] It is not generally associated with pain, except in advanced cases with secondary associated neovascular glaucoma. It has not been associated with infectious or inflammatory conditions, and most patients have no associated systemic medical problems.


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