Bright light therapy (BLT) is a simple, safe, and accessible intervention that can effectively ameliorates sleep disruptions, as well as circadian misalignment and depressive symptoms, and could potentially improve reward system function among patients with OUD. Beyond seasonal affective disorder, BLT has shown efficacy as an intervention for non-seasonal depression, and post-traumatic stress disorder, which all exhibit significant impairment of the dopaminergic reward system and poor sleep quality as key symptoms. Investigators propose to conduct a pilot double-blind, parallel arm, randomized placebo-controlled trial evaluating the feasibility, acceptability, and preliminary efficacy of BLT on reward system functioning among patients undergoing medication-assisted treatment for OUD. The present study will establish feasibility for a larger randomized-clinical trial proposal.