Macular telangiectasia is a condition of the retina, the light-sensing tissue at the back of the eye that causes gradual deterioration of central vision, interfering with tasks such as reading and driving. Type 1, a very rare disease involving microaneurysms in the retina, typically affects a single eye in male patients, and it may be associated with Coats' disease. Type 2 (referred to as MacTel) is the most common macular telangiectasia. It is categorized as "macular perifoveal telangiectasia", a neurodegenerative metabolic disorder, correlated with diabetes and coronary artery disease. It generally affects both eyes and usually affects both sexes equally. Type 3 is an extremely rare, poorly understood neurological disease of the retina. It is characterized by occlusion and telangiectasia of the capillaries of the fovea in one or both eyes, as well as some exudation. Early research Although J. D. Gass originally identified four types of idiopathic juxtafoveolar retinal telangiectasis in 1982, contemporary researchers describe three types collectively known as idiopathic juxtafoveal telangiectasia: macular telangiectasia type 1, macular telangiectasia type 2, and macular telangiectasia type 3. Both macular telangiectasia and age-related macular degeneration (AMD) lead to photoreceptor atrophy and loss of central vision. The two diseases may be distinguished by symptoms, clinical features, and pathogenesis. The natural history of macular telangiectasia suggests a slowly progressive disorder. A retrospective series of 20 patients over 10 to 21 years showed deterioration of vision in more than 84% of eyes, either due to intra-retinal edema and serous retinal detachment (Type 1) or retinal pigment epithelium (RPE) scar formation or neovascularization (Type 2). Type 1 Type 1 idiopathic macular telangiectasia patients are typically males, 40 years old or older. Pathophysiology Type 1 may be defined as an acquired capillary ectasia (a focal expansion or outpouching) and dilation in the parafoveal region, leading to vascular incompetence. Telangiectatic vessels develop micro-aneurysms that leak fluid, blood, and occasionally, lipid. Macular telangiectasia type 1 has been called as a variant of Coats' disease. Treatment Treatment options for Type 1 include laser photocoagulation, intravitreal injections of steroids, or anti-vascular endothelial growth factor (VEGF) agents. Photocoagulation was recommended by Gass and remains to date the mainstay of treatment. It seems to be successful in causing resolution of exudation and VA improvement or stabilization in selected patients. Photocoagulation should be used sparingly to reduce the chance of producing a symptomatic paracentral scotoma and metamorphopsia. Small burns (100–200 μm) of moderate