Coats' disease with retinochoroidal anastomosis.

A 4-year-old girl presented with decreased vision since 3 months. Visual acuity was 20/20 in right eye and counting fingers at 2 meters in the left. Left eye examination revealed exotropia, retinal telangiectasia, extensive subretinal exudation over the macula and exudative retinal detachment suggestive of Coats' disease. Fundus fluoroscein angiography highlighted the hallmark 'light bulb' retinal telangiectasias, macular retinochoroidal anstamosis and peripheral nonperfused retina. The patient was treated with focal laser photocoagulation to the retinal telangiectatic vessels and scatter laser photocoagulation of the non-perfused retina.

Retinochoroidal anastomosis (RCA) represents a communication between the retinal and choroidal circulations and has commonly been reported with neovascular age-related macular degeneration and idiopathic macular telangiectasia (IMT). Other reported causes include polypoidal choroidal vasculopathy, proliferative diabetic retinopathy, retinal artery macroaneurysm, central retinal vein occlusion, sickle cell retinopathy, histoplasmosis, toxoplasmosis, angioid streaks, and post-traumatic choroidal rupture. Published reports of Coats' disease with RCA are rare. Hereby, we describe a case of Coats' disease with RCA.

A 4-year-old girl was brought in with outward deviation of her left eye associated with decreased vision noticed by her mother since past 3 months. On examination, her visual acuity was 6/6 in right eye and counting fingers at 2 m in the left. Right eye was essentially normal [Figure 1]. Anterior segment examination of the left eye was normal except exotropia. Fundus examination of left eye revealed retinal telangiectatic vessels in the temporal periphery with extensive subretinal exudation over the macular area and exudative retinal detachment suggestive of Coats' disease [Figure 2].[1] Fundus fluorescein angiography highlighted the hallmark “light bulb” retinal telangiectasias, macular retinochoroidal anastomosis, and peripheral nonperfused retina [Figure 3]. The patient was treated with focal laser photocoagulation to the retinal telangiectatic vessels and scatter laser photocoagulation of the nonperfused retina.

Figure 1

Retcam images of right eye; (a) color fundus photograph of the posterior pole, (b) mid-arteriovenous phase of fundus fluorescein angiography revealing normal retinal vasculature

Figure 2

Retcam color fundus photograph of left eye revealing retinochoroidal anastomosis over macula (left arrow) and retinal telangiectasias (right arrows)

Figure 3

Retcam fundus fluorescein angiography images of left eye; (a) early and (b) late arteriovenous phases highlighting retinochoroidal anastomosis at macula (left arrow), retinal telangiectasias (right arrows), and nonperfused peripheral retina (oblique arrows)

Although RCA has been reported in many pathological entities, Yannuzzi et al.[2] highlighted the basic underlying pathophysiological mechanisms, staging, clinical, and angiographic characteristics of RCA in retinal angiomatous proliferation, a variant of neovascular age-related macular degeneration.

Subsequently, RCA has been extensively studied in IMT and other telangiectatic pathologies. Coats' disease is a condition with primary retinal telangiectasia characterized by unilateral abnormal telangiectatic segments of blood vessels causing subretinal lipid exudation.[3] RCA has recently been reported with Coats' disease.[4] We agree with Sigler and Calzada that aberrant vascular communicating channels which are known to occur in Coats' disease could favor formation of RCA. Anastomoses have been generally considered a sign of late stage of pathological disease. Furthermore, RCA is known to be a poor prognostic sign for medical treatment of choroidal neovascularization, in general.[5] Further studies are required to elaborate the prognostic significance of RCA in Coats' disease.

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