To investigate the efficacy and safety of intravitreal ranibizumab for the treatment of nonproliferative macular telangiectasia (MacTel) type 2.

Prospective, open-label, uncontrolled, nonrandomized interventional clinical trial.

One eye (disease stage 2 or 3) of each patient (n = 10) with nonproliferative MacTel type 2 was injected with 0.5 mg ranibizumab at monthly intervals for one year. Visual acuity, angiographic findings, and retinal thickness were assessed at each visit. The primary endpoint was the change in best-corrected distance visual acuity after one year compared to baseline.

Mean visual acuity showed a transient increase in the study eye. However, after 12 months of treatment there was no significant change of visual acuity compared to baseline or compared to the fellow eye. Fluorescein angiography revealed a decrease of telangiectatic-appearing capillaries and of late-phase leakage, which was accompanied by a topographically related significant reduction in macular thickness. Three to 5 months after the last treatment, angiographic appearance and retinal thickness were similar to baseline. In one patient, the last intravitreal injection was not performed because of safety concerns after a transitory ischemic attack. Otherwise, no serious adverse events were observed.

The angiographic and tomographic effects after intravitreal inhibition of vascular endothelial growth factor (VEGF) using ranibizumab implicate a pathophysiological role of the VEGF pathway in nonproliferative MacTel type 2. As the morphologic response was not associated with a clear functional benefit, and because of the transient nature of the treatment effect, monthly intravitreal ranibizumab is not recommended for the nonproliferative disease stage of MacTel type 2.