RT Journal Article A1 Karanjia, Rustum A1 Berezovsky, Adriana A1 Sacai, Paula Yuri A1 Cavascan, Nivea Nunes A1 Liu, Henry Yuheng A1 Nazarali, Samir A1 Moraes-Filho, Milton Nunes A1 Anderson, Kirsten A1 Tran, Jeffrey Show A1 Watanabe, Sung EunSong A1 Moraes, Milton Nunes A1 Sadun, Federico A1 DeNegri, Anna Maria A1 Barboni, Piero A1 do Val Ferreira Ramos, Carolina A1 La Morgia, Chiara A1 Carelli, Valerio A1 Belfort, Rubens, Jr A1 Coupland, Stuart Glenn A1 Salomao, Solange Rios A1 Sadun, Alfredo A. T1 The Photopic Negative Response: An Objective Measure of Retinal Ganglion Cell Function in Patients With Leber's Hereditary Optic Neuropathy JF Investigative Ophthalmology & Visual Science JO Invest. Ophthalmol. Vis. Sci. YR 2017 DO 10.1167/iovs.17-21773 VO 58 IS 6 SP BIO300 OP BIO306 SN 1552-5783 AB The photopic negative response (PhNR) is a slow negative component of a flash photopic full-field ERG that has been shown to be specific for retinal ganglion cell (RGC) activity. Direct evaluation of RGC function is desirable in patients with Leber's hereditary optic neuropathy (LHON) in which the loss of central acuity can make it difficult to monitor patients with standard metrics. The purpose of this study was to evaluate the use of PhNR as an objective noninvasive clinical metric in LHON. Full-field photopic ERG recordings were collected in subjects with the mt.11778G>A/ND4 LHON mutation using a red on blue stimulus. The PhNR was identified using a computer-based automated detection system, and data were manually examined to remove movement artifacts. The PhNR amplitude was compared between controls (n = 13), carriers (n = 17), and affected (n = 6). Mean PhNR amplitude decreased significantly across groups (P < 0.0001). Post hoc Tukey's test revealed a significant decrease in PhNR amplitude between carriers and controls (P < 0.05) and between carriers and affected (P < 0.01). We are able to demonstrate that the PhNR amplitude is significantly decreased in patients affected by LHON compared to carriers in a well-described pedigree. Surprisingly, there was also a decrease in PhNR in carriers, suggesting potential subclinical RGC dysfunction in some carriers. This is important in patients affected with LHON who typically have a dense central scotoma. The PhNR may be a useful objective outcome measure for future clinical trials. RD 3/5/2021 UL https://doi.org/10.1167/iovs.17-21773