Coats disease

Coats disease is a rare, non hereditary eye condition characterized by abnormal development of blood vessels in the retina. These vessels become dilated, tortuous, and fragile, leading to leakage of fluid, proteins, and lipids into and under the retina. This leakage can cause fluid accumulation, hemorrhages, and in severe cases, exudative retinal detachment, secondary glaucoma, and even blindness.

The disease typically affects one eye (in about 90% of cases) and usually manifests in early childhood, with an average age of diagnosis around five years. Boys are more commonly affected than girls. The exact cause of Coats disease is currently unknown.

The most common initial sign of Coats disease is often a "white pupil" (leukocoria), which results from light reflecting off the fluid deposits or detached retina. Other symptoms may include decreased vision, a new squint (strabismus), or in more advanced stages, flashes of light (photopsia) and floaters in the visual field.

Young children may not complain about vision loss, as they often adapt easily to changes or the unaffected eye compensates for the impaired vision. Eye pain is not a common symptom in the early stages but can occur in advanced cases of secondary glaucoma, where intraocular pressure significantly increases.

The diagnosis of Coats disease is typically made through a comprehensive eye examination. Ophthalmoscopy, an examination of the back of the eye, allows the doctor to visualize the dilated and tortuous retinal blood vessels, as well as the fluid and lipid exudates. Often, the diagnosis is made in later stages of the disease when symptoms become more apparent.

Additional diagnostic tests include fluorescein angiography, which highlights the leakage from the abnormal blood vessels, and ocular ultrasound. Ultrasound is particularly important to rule out other conditions in children, such as retinoblastoma, an eye tumor that can present with similar symptoms like a white pupil.

The goal of treatment for Coats disease is to destroy or constrict the leaking retinal blood vessels to prevent further leakage and preserve vision as much as possible. In the early stages of the disease, treatment may involve laser photocoagulation or cryotherapy (freezing treatment). These treatments are directed at the abnormal blood vessels. In selected cases, a retina specialist may add injections of anti VEGF medicines or corticosteroids into or around the eye to help reduce fluid and swelling. This use is often outside the licensed indication, and injections do not replace treatment of the abnormal vessels. Benefits must be weighed against risks, including scarring and traction on the retina reported with some injection treatments.

In more advanced cases, where significant retinal detachment or other complications are present, surgical intervention may be necessary. The type of surgery depends on the severity of the condition and the existing complications. It is important to note that treatment does not cure the disease but aims to manage its progression and prevent further damage.

Without treatment, Coats disease can lead to severe complications, including exudative retinal detachment, secondary glaucoma (increased intraocular pressure), cataracts, and recurrent vitreous hemorrhages. These complications can result in significant vision loss and even blindness in the affected eye.

The prognosis (expected outcome) varies greatly and depends on the stage of the disease at diagnosis and the response to treatment. Early diagnosis and appropriate intervention can improve the chances of preserving some vision. However, in advanced cases, even with treatment, it may not be possible to restore lost vision.

After diagnosis and treatment, regular follow up with an ophthalmologist is necessary to assess the disease's response to treatment, identify any new complications, and consider further interventions if needed. The frequency of follow up will be determined by the treating physician based on the specific condition.

It is important to seek immediate medical attention from an ophthalmologist if any new visual changes are noticed, such as a sudden decrease in vision, the appearance of a white pupil, a new squint, eye pain, or any other concerning signs. Early detection of these changes can be crucial for preserving eye health.