OBJECTIVE Our study is aimed at evaluating the role of UVB light in inducing cytotoxicity in an in vitro model. METHODS RGC-5 and ARPE-19 cells were exposed to different time periods of UVB light: 0, 15, 30, and 45 min. They were subsequently examined for changes in cell morphology, cell viability (neutral red uptake assay), generation of reactive oxygen species (ROS), expression of bax, bcl-2 and cytochome C by reverse transcriptase polymerase chain reaction and western blot, respectively. RESULTS Dose-dependent reduction in cell viability to UVB light was demonstrated with parallel increase in ROS. Increased duration of exposure (>15 minutes), was associated with increased expression of bax and cytochrome C, and absence of bcl-2 expression. CONCLUSIONS UVB light exposure results in cell cytotoxicity. The concomitant generation of ROS and expression of apoptotic markers suggests the role of oxidative stress in UVB-mediated apoptosis in an in vitro model of retinal ganglion and pigment epithelial cells.