Sir,

We thank Koay et al1 for their interest in our paper2 and for presenting an interesting case. We feel that the effectiveness of intravitreal bevacizumab varies among patients with idiopathic macular telangiectasia (MacTel) type 1. In our patients, visual acuity improved only in one of the five eyes at 12 months after the initial treatment. However, Gamulescu et al3 reported that a single intravitreal bevacizumab markedly increased the visual acuity in a MacTel type 1 patient, and Koay et al1 showed a case of MacTel type 1 successfully treated with intravitreal bevacizumab.

One possible reason for this discrepancy may be the different treatment protocol. In our study, the protocol was as follows: all patients were examined for changes in the visual acuity or retinal thickness 2 weeks after treatment; if macular oedema did not reduce, additional treatments were performed one to two times at the discretion of the physician at 4-week intervals. In contrast, Koay et al1 administered a monthly injection of intravitreal bevacizumab three times from the baseline. Thus, a prospective study using a fixed protocol in a larger number of patients is necessary to confirm the efficacy of bevacizumab for the treatment of MacTel type 1.

Recently, He et al4 reported that Coats’ disease is associated with an increased intraocular vascular endothelial growth factor (VEGF) level. In their study, intraocular fluid was obtained from three children and one adult diagnosed with Coats’ disease. Currently, this disorder is considered as Coats’ disease in childhood and is usually referred to as MacTel type 1 when it is diagnosed in an adult, and involves the macula. Further studies on intraocular VEGF level in MacTel type 1 or adult-onset Coats’ disease will show whether VEGF has a function in the pathogenesis of MacTel type1.