This study is an open-label, pilot study of intravitreal injections of ranibizumab in participants with macular telangiectasia. Genentech will supply the ranibizumab for this trial. Five study participants, with neovascularization, will be selected for this study. The study eye in participants who present with bilateral macular telangiectasia will be designated as the eye with the greater severity of involvement as determined by visual acuity measurements, fluorescein angiography and OCT results. However, in the case where the more severely affected eye is judged to unlikely benefit from treatment due to irreversible structural changes (extensive atrophy and pigmentary change, chronic macular scarring), then the less severely affected eye may be considered. In cases where both eyes are equivalent, the investigator and participant will determine the study eye. The fellow eye will be treated according to standard-of-care. Because the pathogenesis of this condition is unknown, one can only speculate on the possible role of vascular endothelial growth factor (VEGF) in this condition. The leakage seen on fluorescein angiogram reflects on the endothelial dysfunction of the retinal vessels although it is not certain that this may be a primary or a secondary condition. The fluorescein leakage of macular telangiectasia resembles that of diabetic retinopathy where VEGF has proven to be important in its pathogenesis. The development of neovascularization, which often begins as intra-retinal neovascularization, which then develops into subretinal and choroidal neovascularization, suggests that VEGF may also be implicated in this process. For these reasons, we believe it is important to test the possible role of ranibizumab therapy with intravitreal injections of ranibizumab. We will learn about the feasibility of this treatment while we learn about any safety issues. We do not understand fully the cause of vision loss in the early stages of the disease. It is evident that the neovascular process will decrease vision in a similar process as that of other causes of neovascularization such as age-related macular degeneration.

National Institute of Health (NIH)
National Eye Institute (NEI)
Investigator-Initiated Intramural Research Projects (ZIA)
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U.S. National Eye Institute
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Charbel Issa, Peter; Gillies, Mark C; Chew, Emily Y et al. (2013) Macular telangiectasia type 2. Prog Retin Eye Res 34:49-77
Meleth, Annal D; Toy, Brian C; Nigam, Divya et al. (2013) Prevalence and progression of pigment clumping associated with idiopathic macular telangiectasia type 2. Retina 33:762-70
Chew, Emily Y (2012) How prevalent is macular telangiectasia type 2? Ophthalmic Epidemiol 19:183-4
Toy, Brian C; Koo, Euna; Cukras, Catherine et al. (2012) Treatment of nonneovascular idiopathic macular telangiectasia type 2 with intravitreal ranibizumab: results of a phase II clinical trial. Retina 32:996-1006