Coats' disease is a rare congenital, nonhereditary eye disorder, causing full or partial blindness, characterized by abnormal development of blood vessels behind the retina.

[2] Symptoms typically begin as blurred vision, usually pronounced when one eye is closed (due to the unilateral nature of the disease).

Deterioration is likely to begin in the upper part of the vision field as this corresponds with the bottom of the eye where blood usually pools.

Initially, these may be mistaken for psychological hallucinations, but are actually the result of both retinal detachment and foreign fluids mechanically interacting with the photoreceptors located on the retina.

Children with yellow-eye in photographs are typically advised to immediately seek evaluation from an optometrist or ophthalmologist, who will assess and diagnose the condition and refer to a vitreo-retinal specialist.

Coats' usually affects only one eye (unilateral) and occurs predominantly in young males 1/100,000, with the onset of symptoms generally appearing in the first decade of life.

Blood leaks from the abnormal vessels into the back of the eye, leaving behind cholesterol deposits and damaging the retina.

[2][5] On funduscopic eye examination, the retinal vessels in early Coats' disease appear tortuous and dilated, mainly confined to the peripheral and temporal portions of retina.

[2] In moderate to severe Coats' disease, massive retinal detachment and hemorrhage from the abnormal vessels may be seen.

Laser surgery or cryotherapy (freezing) can be used to destroy the abnormal blood vessels, thus halting progression of the disease.