To characterize changes in macular structure and vascularity seen in premature-birth adults. Retrospective review of adult patients seen in our clinic from July 2018 to November 2020 with history of premature birth not requiring treatment for retinopathy of prematurity (ROP), as well as healthy controls. Swept-source OCT-angiography (OCT-A) scans were analyzed for various parameters related to macular structure and vascularity. Statistical analysis was performed using univariate linear regression. Thirty-four eyes were included (17 eyes from 10 premature-birth adults, 17 eyes from 11 control patients). Prematurity was associated with vascular changes on OCT-A: decreased foveal avascular zone (FAZ) area (p=0.001), decreased FAZ circularity index (p<0.001), decreased superficial capillary plexus vessel (CPV) density (p=0.02), and decreased deep CPV density (p<0.001). Prematurity was also associated with structural changes: shallower foveal pit depth (p<0.001), decreased cube average thickness (CAT) (p=0.005), and increased central subfield thickness-to-CAT ratio (p=0.002). This is the largest published series of OCT-A data for premature-birth adults. Even without a history of ROP treatment, premature birth is associated with multiple changes to macular structure and vascularity that persist into adulthood. These include a smaller, more irregularly shaped FAZ, decreased juxtafoveal vascular density, and a shallower foveal pit.