Multifocal electroretinography in patients with macular telangiectasia type 2.

Abstract

To evaluate the multifocal electroretinographic (mfERG) response in patients with macular telangiectasia (MacTel) type 2. Prospective, observational case series. Thirty-four eyes of 18 patients diagnosed with nonproliferative MacTel type 2 underwent recording of best-corrected visual acuity (BCVA), fundus fluorescein angiography, spectral domain optical coherence tomography (SD-OCT) and mfERG using 61 hexagonal elements, in accordance with ISCEV guidelines. The P1 average response densities and implicit times of the first-order kernel responses were grouped into five concentric rings centred on the fovea. Data from the left eyes of cases (18 eyes) were compared with 34 eyes of age- and sex-matched controls. Correlation analyses were performed between BCVA, mfERG parameters and SD-OCT measurements. Mean BCVA of the cases was 0.3 ± 0.26 ranging from 0 to 1. On SD-OCT, mean central foveal thickness was 205.78 ± 40.92μm and average mean macular thickness was 248.22 ± 23.08μm. Mean P1 amplitudes were significantly decreased in eyes with MacTel type 2 as compared to controls in ring 1 (p = 0.039). Mean P1 implicit time in all the rings was comparable between the two groups. BCVA was significantly and negatively correlated with P1 amplitude in ring 1 (r = - 0.518, p = 0.028) in eyes with MacTel type 2. mfERG reflects localised inner retinal dysfunction in MacTel type 2. Correlation with BCVA reinforces that mfERG should be used to objectively assess the macular function in these patients.