OCT of Outer Retinal Hyperreflectivity, Neovascularization, and Pigment in Macular Telangiectasia Type 2

Abstract

To investigate whether outer retina hyperreflectivity (ORHR) and outer retina neovascularization (ORNV) are visible in eyes with macular telangiectasia type 2 (MacTel 2) before pigment proliferation is visible. Retrospective study in a cohort of patients from the MacTel Project. Thirty-nine MacTel 2 eyes without pigment on color fundus photography (CFP) at presentation were studied over a mean of 36.6 months (range, 13.8-50.4 months; standard deviation, ±10 months). All patients routinely underwent Snellen best-corrected visual acuity (VA) measurement, CFP, spectral-domain OCT, and OCT angiography (OCTA). Pigment in the macula on CFP, best-corrected VA, presence of ORHR, presence of ORNV, presence and surface of ellipsoid zone (EZ) loss, and occurrence of ORHR, ORNV, and pigment. At presentation, 13 eyes showed no EZ loss, and no ORHR nor change was observed during the follow-up. In the 19 eyes with only EZ loss at baseline, ORHR appeared in 6 eyes, and one of them also showed visible pigment on CFP. Among the 7 eyes with ORHR and ORNV at baseline, pigment proliferation became visible in 4 eyes. Overall, at the end of follow-up, 14 eyes showed ORNV and 13 showed ORHR, of which 5 showed pigment on CFP. In all cases, ORHR on spectral-domain OCT corresponded to ORNV on OCTA. Hyperreflectivity and neovascularization developed within an EZ loss area or at its edge. At the end of follow-up, although the EZ loss area was larger in eyes with ORHR, pigment, or both than in eyes without any pigment migration (0.33 mm2 vs. 0.94 mm2; P= 0.01), VA was similar in both groups (0.32 logarithm of the minimum angle of resolution [logMAR] vs. 0.35 logMAR; Snellen equivalent, 20/40 vs. 20/50; P= 0.64). Spectral-domain OCT and OCTA showed that in MacTel 2 eyes, ORHR was associated with ORNV on OCTA and most often did not correspond to pigmentation on CFP. When ORNV developed, hyperreflectivity appeared along the abnormal capillary tracts after a mean follow-up of 36 months. In most cases, the presence of ORHR was not associated with rapid vision loss.