NAC Attack, a phase-3, multicenter, randomized, placebo-controlled trial with retinitis pigmentosa: OCT Reading Center - Abstract The objective of the activities proposed in this application is to provide spectral-domain optical coherence tomography (SD-OCT) Reading Center support to the NAC Attack study. This project's primary goal is to identify by OCT the effect of N-acetyl cysteine (NAC) compared to control treatment on progression of retinitis pigmentosa from baseline to study end, as assessed by the cumulative loss in foveal-centered ellipsoid zone (EZ) length. An exploratory goal is to determine NAC's effect, when compared to control, on the cumulative loss of the EZ area. The primary and exploratory objectives will be accomplished through the following specific aims: Specific Aim 1: Provide the infrastructure to process SD-OCT images submitted by NAC Attack clinical sites to the OCT Reading Center. Specific Aim 2: Train and certify NAC Attack clinical site personnel on methods to acquire and transmit images to the OCT Reading Center. Specific Aim 3: Provide Reliable, Timely, Reproducible, and Systematic Grading of submitted SD-OCT. To achieve these aims, we will use in-house developed, validated, and 21 CFR 21-compliant stand-alone web-based systems to provide secure methods for clinical sites to transmit electronic SD-OCT data to the OCT Reading Center, to store and back-up submitted data, assign the images to be graded to Reader, and to provide electronic data entry forms into which Readers will enter their image quality assessment data. Readers will use our custom-developed and validated software to manually grade the foveal EZ length and automatically quantify the EZ area in the assigned images. The foveal EZ length and EZ area data will be exported directly from software into a database that will be transferred to the Coordinating Center through a secure portal. The OCT Reading Center will also implement materials and methods for Reader and clinical site OCT technician certification and training, rigorous quality control for manual and automatic gradings, and support study goals as an image resource for recruitment, Study Group meetings, presentations, and publications.