Multimodal characterization of macular telangiectasia type 2 and correlation with multifocal electroretinogram

Abstract

1. Purpose: To study the correlation of multimodal imaging in macular telangiectasia (Mac Tel) with foveal function on multifocal electroretinogram (mfERG)2. Methods: Eyes with non- proliferative Mac Tel diagnosed based on clinical examination, optical coherence tomography (OCT), autofluorescence (AF), fluorescein angiography (FA), OCT angiography (OCTA). Control group with normal eye exam included for multifocal electroretinogram.Staging of OCT, OCTA, AF and FA done in Mac Tel subjects. mfERG done in study subjects and controls. Correlation of imaging modalities and P1 amplitudes at fovea (ring 1) studied in terms of correlation co-efficient.3. Results: Twenty nine eyes of 16 patients of Mac Tel and 25 eyes of 19 controls were included. BCVA was 0.38 ± 0.266 in study eyes and 0 in control eyes. On OCT it was observed that 41.4% Mac Tel eyes (n = 12) belonged to stage 3, 37.9%(n = 11)) eyes belonged to stage 2 and 20.7% (n = 6) eyes belonged to stage 1. AF- Stage 3 comprised of 75.9% eyes (n = 22); 4 eyes belonged to stage 2 and 3 eyes to stage 1. On FA, 18 eyes belonged to stage 3 (62.1%); stage 2 was seen in 1 (3.4%) eye and stage 1 was seen in 10 (34.5%) eyes. There was decrease in P1 amplitudes from R1(p < 0.001), R2( 0.001), R3 (< 0.001) and R4 (0.001) in Mac Tel eyes compared to control eyes but not in R5 (p 0.785). SD- OCT had positive correlation with FAF (CC 0.747,p < 0.001) FFA (CC 0.775, p < 0.001) and R1P1 (CC 0.682, p < 0.001). With OCTA there was no significant correlation (CC 0.318, p 0.093). There was positive and significant correlation of OCT (0.682,<0.001), OCTA (0.379,p 0.042) AF ( 0.635, p < 0.001) and FA (0.495, p < 0.006) with R1P1.4. Conclusions: Existing multimodal imaging systems can be reliable indicators of foveal function as on mfERG.