Exudative macular neovascularization before visible pigmentation in Macular Telangiectasia Type-2 (MacTel)

Purpose: To examine multimodal imaging findings in eyes before and after the onset of exudative macular neovascularization (ExMNV) bypassing the stage of pigmentation in Macular Telangiectasia Type-2 (MacTel). Methods: From a total of 798 patients, MacTel eyes with ExMNV that exhibited no signs of focal hyperpigmentation on color fundus photo, fundus autofluorescence and spectral-domain optical coherence tomography (OCT) were retrospectively evaluated. Results: There were 16 eyes of 16 patients (2%) with a mean age of 50.60 ± 9.82 years. Among them, 11 eyes had ExMNV at the time of examination, while the remaining 5 eyes developed ExMNV during the follow-up period, all lacking pigment when it occurred. The average time for ExMNV development in the 5 eyes was 27.6 months (range: 11–46 months). Preceding signs of ExMNV included right-angled vessels and telangiectatic leaks causing the following OCT changes - temporal parafoveal thickening in 3 eyes, minimal intraretinal fluid pockets in 3 eyes, convex hypo-reflective subretinal space in 2 eyes, and subretinal fluid in 2 eyes. With further declension/descent of inner into outer retina, progression of ellipsoid zone (EZ) loss was seen and outer retinal hyper-reflectivity formed in areas with pre-existing EZ loss with visual acuity decline. Multiple retinal vessels formed an anastomosis with each other and extended into the center of the subretinal neovascular lesion. Conclusion: Patients with early MacTel can proceed directly to ExMNV without pigmentation. Recognizing the signs before ExMNV develop will allow for closer follow-up and earlier treatment of these patients to prevent irreversible visual loss.