Purpose: To evaluate the clinical features of Type 1 idiopathic macular telangiectasia (IMT) followed up for 2 years.Methods: Forty-nine patients with unilateral Type 1 IMT were examined. Thirty-one IMT eyes were treated with direct laser photocoagulation and/or intravitreal bevacizumab; the remaining 18 eyes, with good vision or slight macular edema, were untreated. Changes in best-corrected visual acuity and central retinal thickness between baseline and 24 months after the initial visit were examined.Results: Of 49 eyes, nine were treated with direct laser photocoagulation, 12 with laser photocoagulation and intravitreal bevacizumab, 10 with intravitreal bevacizumab monotherapy, whereas 18 did not receive any treatment. The mean logarithm of the minimum angle of resolution best-corrected visual acuity was 0.20 +/- 0.19 (median, 20/29) and 0.13 +/- 0.22 (median, 20/25) at baseline and 24 months, respectively (P = 0.023). The mean central retinal thickness was 375.0 +/- 94.5 mu m and 315.3 +/- 78.5 mu m at baseline and 24 months, respectively (P < 0.001). Retinal vein occlusion and retinal macroaneurysm occurred in six eyes and one eye, respectively, during follow-up.Conclusion: Treatment with laser photocoagulation and/or intravitreal bevacizumab may be effective for Type 1 IMT, 36.7% of IMT eyes required no treatment over a 2-year follow up, and other retinal vascular events were not uncommon.