SD-OCT stages of progression of type 2 macular telangiectasia in a patient followed for 3 years

Purpose: To describe the natural course of type 2 idiopathic macular telangiectasia (MT) using spectral-domain optical coherence tomography (SD-OCT). Methods: Analysis of the different stages of progression of type 2 MT during a period of 3 years using multimodal imaging, including SD-OCT correlated with angiographic and autofluorescence images. The analysis of the different steps was obtained initially from the first eye, then successively from the fellow eye when progressive changes appeared. Results: The earliest visible alteration at SD-OCT was the interruption of the interface between inner segment and ellipsoid (IS/EL) (stage 1). The second stage was characterized by the complete interruption of both IS/EL interface and external limiting membrane (stage 2). At the next step, a wide disruption of the outer nuclear layer was noted (stage 3). The fourth stage showed a complete disorganization of the inner layers with aspect of fusion of the inner retinal layers associated with progressive atrophy of the outer layers (stage 4). Hyper-reflective deposits were found in both the internal and external retinal layers (stage 5). Small intraretinal cystoid spaces appeared in the different retinal layers (stage 6). This last feature was an earlier manifestation of the typical intraretinal cysts that are the wellknown OCT appearance of type 2 MT. Conclusions: We describe the 6 steps of progression from earlier SD-OCT findings that led to a complete disorganization and fusion of the inner layers (probably due to changes in the Muller cells) to the typical intraretinal cysts.