Outer Retinal Tubulation in Subretinal Neovascularization Associated with Macular Telangiectasia Type 2

To describe characteristics of outer retinal tubulation (ORT) in eyes with subretinal neovascular membrane (SRNVM) associated with Macular Telangiectasia type 2 (MacTel type 2).A retrospective analysis of longitudinal spectral domain optical coherence tomography (SD-OCT) scans of 46 eyes of 30 patients with SRNVM associated with MacTel type 2 was performed. To identify ORTs, each B-scan image of the macular cube (512 X 128) scan on the Cirrus® SD-OCT was reviewed. Changes in ORT characteristics, including location, size, reflectivity of the borders, and internal reflectivity, were noted during an average follow-up period of 18 months.Ten ORTs were detected in 7 of 46 eyes (15.2%); SRNVM showed no activity in six of these seven eyes. ORT was seen as round or ovoid hyporeflective spaces with hyperreflective borders, and measured 56 to 206 μm in height and 120 to 357 μm in width. An average of 1 bevacizumab injection (range: 0-2) was administered before at least one ORT was diagnosed. The mean interval between the last injection and detection of ORT was 10.2 months (range: 1-48 months). Over the 18-month follow-up period, ORTs were unchanged in four eyes, while in the remaining three eyes ORTs underwent structural changes. Five ORTs disappeared, four new ORTs appeared, and one ORT disappeared and reappeared. The size and the shape of ORT did not change, except in one case.Outer retinal tubulation can develop in eyes with MacTel type 2 associated SRNVM, with similar characteristics to ORT found in other degenerative diseases. ORTs may undergo dynamic structural modifications over time, with or without ongoing bevacizumab treatment.