Idiopathic Macular Telangiectasia

Abstract

Idiopathic macular telangiectasia is a spectrum of rare disorders with the common feature of abnormalities of the perifoveal capillaries. In macular telangiectasia type 1, aneurysmal changes, lipid exudation, and cystoid macular edema predominate. The clinical presentation resembles a mild variant of Coats’ disease. Macular telangiectasia type 2 is a slowly progressive, neurodegenerative disorder that is typically diagnosed in the fifth and sixth decades of life. Commonly referred to as MacTel, this form is characterized by typical blue reflectance changes and cavitary spaces on optical coherence tomography that can proceed capillary changes. Characteristic features include perifoveal capillary telangiectasia temporal to the fovea and corresponding leakage on fluorescein angiography. Right-angle vessels, perifoveal retinal crystalline deposits, and retinal pigment epithelium migration are also typical. Subretinal neovascular proliferation can occur in late stages. Macular telangiectasia type 3 is a poorly understood condition with a familial component and systemic associations. MacTel is the most frequently occurring form and has been the most extensively characterized. Historical strategies for treating MacTel involved laser destruction of abnormal vasculature using various modalities, resulting in limited success. With the advent of anti-vascular endothelial growth factor therapies, intravitreal agents and steroids have been trialed with variable results. As understanding of the underlying pathophysiologic mechanisms driving these disease processes has evolved, there has been a shift toward development of neuroprotective treatment strategies. International collaboration through the MacTel Project has accelerated the pace of discovery of this disease, and promising research in this area is currently underway.