The classic findings in Coats disease are yellow subretinal and intraretinal lipid exudates associated with retinal vascular abnormalities—most often telangiectasia, tortuosity, aneurysmal dilatations, and retinal capillary nonperfusion. The clinical presentation varies, ranging from mild changes to total retinal detachment (Fig 25-29).
Males are affected more frequently than females, and the condition is usually, but not always, unilateral. The average age at diagnosis is 6–8 years, but the disease has also been observed in infants. The etiology of Coats disease is unknown. Associations with various gene deletions have been reported, but the disease is isolated in most cases.
Figure 25-29 Advanced Coats disease with extensive subretinal exudation and total retinal detachment. Superior retinal macrocysts—associated with macroaneurysms and dilatated, tortuous vessels—are present.
(Courtesy of Scott C. Oliver, MD.)
The diagnosis of Coats disease requires the presence of abnormal retinal vessels, which occasionally are small and difficult to find. The subretinal exudate is thought to come from the leaking anomalous vessels. Fluorescein angiography may be helpful in identifying leakage from the telangiectatic vessels and in assessing the effectiveness of therapy (Fig 25-30). Oral fluorescein can be used in place of intravenous fluorescein in the ambulatory setting to monitor disease and avoid examination under anesthesia.
Figure 25-30 Coats disease. A, Ultra-wide-angle color photograph reveals foveal exudation with temporal macroaneurysms and telangiectasias. Inset shows magnification of macroaneurysms and telangiectasias. Subtle nasal telangiectasias are also present. B, Image obtained with oral fluorescein angiography shows extensive leakage from temporal macroaneurysms, mild leakage from temporal and nasal telangiectasias, and macular leakage with some staining.
(Courtesy of Scott C. Oliver, MD.)
The differential diagnosis includes persistent fetal vasculature, ROP, toxocariasis, FEVR, Norrie disease, retinal dysplasia, endophthalmitis, leukemia, and retinoblastoma. Calcium is frequently detected by ultrasonography in retinoblastoma but is distinctly rare in Coats disease. Coats disease often presents with xanthocoria (yellow pupillary reflex), whereas retinoblastoma presents with leukocoria.
Treatment is directed at obliterating the abnormal leaking vessels and includes cryotherapy, laser photocoagulation, vitrectomy, and silicone oil. Exudative retinal detachments and subretinal fibrosis develop in eyes with progressive disease. Once the fovea is detached and the subretinal exudate becomes organized, the prognosis for restoration of central vision is poor. Use of intravitreal bevacizumab in addition to laser treatment has been reported, but one study found that this approach was associated with a higher incidence of vitreoretinal fibrosis and tractional retinal detachment.
Mulvihill A, Morris B. A population-based study of Coats disease in the United Kingdom II: investigation, treatment, and outcomes. Eye (Lond). 2010;24(12):1802–1807.
Ramasubramanian A, Shields CL. Bevacizumab for Coats disease with exudative retinal detachment and risk of vitreoretinal traction. Br J Ophthalmol. 2012;96(3):356–359.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.