Progression of vascular changes in macular telangiectasia type 2: comparison between SD-OCT and OCT angiography.

In SD-OCT, the severity of MacTel is characterized by progressive EZ loss, which may be used as a simple clinical "disease severity scale". In addition, OCT-A enables visualization and quantification of vascular patterns with mathematical methods. The morphological progression of the disease correlated significantly with progressive vascular changes, especially in respect of the numbers of branches and vessel segments as well as fractal dimension. This suggests that the severity of neurodegenerative and neurovascular changes develops in parallel and that the analysis and quantification of the vascular changes in the superficial and deep capillary networks may become an additional parameter for future treatment trials. Moreover, the significant association between hyperreflective material progressively visible on SD-OCT in the OR, which most often contains vessels in OCT-A, and advancing SD-OCT severity grades, as well as vascular changes in OCT-A, supports the concept of retinal neovascularization in the OR in patients with advanced MacTel.