Mark Gillies

　　澳大利亚悉尼眼科医院

　　Idiopathic Macular Telangiectasia type 2(MT2)is an uncommon retinal vascular disease characterised by parafoveal telangiectasis in both eyes and hyperfluorescence on fluorescein angiography without cystic oedema.The condition is often mis-diagnosed，even by retinal specialists，as age-related macular degeneration.Clinically the telangiectasis most often involves the temporal parafovea and can be accompanied by right-angled venules，reduced retinal transparency，and superficial crystalline deposits.Loss of vision，if it occurs at all，develops gradually over many years.In around 20%of cases，subretinal neovascularisation develops leading to more rapid decline in vision.Optical coherence tomography often shows inner or outer retinal cavitation.Autofluorescence characteristically shows loss of central masking by macular pigment.Although the cause of Type 2 IMT is unknown，familial clustering has been observed suggesting that there may be a genetic component.Currently there is no treatment，however finding an effective intervention to prevent loss of vision from MT2 is the goal of the MacTel project，an international collaboration of 30 clinical and laboratory science centres(see：www.mactelresearch.org).Histological studies of the only known post mortem specimen from a patient with MT2 suggests that the disease might be caused primarily by a Muller cell defect.