by Wendy Strouse Watt, O.D.
Retinal telangiectasias are a group of rare, idiopathic (a disease having no known cause), congenital retinal vascular anomalies affecting the retinal capillaries. The conditions are characterized by dilation and tortuosity of retinal vessels and formation of multiple aneurysms (localized, pathological, blood-filled dilatations of a blood vessel caused by a disease or weakening of the vessel’s wall), with different degrees of leakage and lipid exudates (that ooze from the blood vessels). Idiopathic JXT, Leber’s miliary aneurysms, and Coats’ disease are three types of retinal telangiectasias.
Idiopathic juxtafoveolar retinal telangiectasia (JXT) is commonly characterized by slow vision loss beginning in adulthood. JXT may be unilateral or bilateral. The unilateral form only affects men and typically is not discovered until after age 40. Patients with unilateral JXT are usually asymptomatic. Dilated and kinked vessels, along with microaneurysms, in the parafoveal (beside the fovea, the center of the macula) capillary network are the hallmark of the condition. Leakage may cause macular edema and reduced visual acuity. Fundus assessment often reveals parafoveal dot and blot hemorrhages and, rarely, exudates. Current convention divides patients into one of three sub-categories of disease. In group 1, the telangiectasis appears to be caused by retinal capillary leakage. In group 2, the telangiectasis is most likely caused by capillary diffusion abnormalities. Capillary occlusion is suspected of causing the telangiectasis in group 3 patients. Group 1 patients are primarily male. The telangiectasia is unilateral in most cases and easily visible. It is suspected that this form of JXT may be a mild presentation of Coats’ disease. Group 2 patients are characterized by retinal juxtafoveolar telangiectasia, minimal exudation, superficial retinal crystalline deposits, and right-angle venules (small veins, especially one joining capillaries to larger veins). As the disease progresses, intraretinal pigment plaques and subretinal neovascularization (new blood vessel growth) develop. Group 3 patients are diagnosed with bilateral, easily visible telangiectasia, minimal exudation, and capillary occlusion. Gass and Blodi (1993) postulate this category of disease to be related to systemic conditions, such as gouty arthritis or hypoglycemia (low blood sugar).
The differential diagnoses (those that need to be ruled out) for idiopathic JXT includes retinal vascular disorders (such as branch retinal vein occlusion), diabetic retinopathy, sickle-cell retinopathy, Eales’ disease, and retinopathy of prematurity.
Leber’s miliary aneurysms represent a more severe form of telangiectasia. Patients often present in middle-age with a drop in VA. Fundus (retinal) findings include lipid deposition at the macula and dilation of arterioles and venules. Cryotherapy or photocoagulation may be needed to destroy the area of vascular abnormality. (For more information about Leber’s miliary aneurysms, see “Eye Diseases and Conditions.”)
Coats’ Disease is a very severe, unilateral form of retinal telangiectasia that is most often seen in boys before age 10. Patients often present with strabismus (an eye turn) or leukocoria (a white pupil). The differential diagnoses includes retinoblastoma (a malignant tumor of the retina that causes a white pupil) and retinopathy of prematurity. The disease is characterized by large areas of dilated, tortuous retinal blood vessels which overlie intra- and sub-retinal yellow exudate at the posterior pole (the optic nerve and macular areas) and in the periphery. Retinal edema may also be persistent, causing decreased acuity when it reaches the macula. Ischemia or decreased blood flow may develop as well, with neovascularization and subsequent vitreal hemorrhage and retinal detachment. Spontaneous resolution is rare and the disease often progresses to massive sub-retinal exudation, exudative retinal detachment, rubeosis iridis (neovascularization of the colored part of the eye), secondary cataract, and secondary glaucoma. Treatment includes cryotherapy and photocoagulation to destroy the abnormal vessels and to prevent retinal detachment.