Updated project metadata. During oxidative stress, reactive oxygen species (ROS) can modify and damage cellular proteins. In particular, the thiol groups of cysteine residues can undergo reversible or irreversible oxidative post-translation modifications (PTMs). Identifying the redox-sensitive cysteines on a proteome-wide scale can provide insight into those proteins that act as redox sensors or become irreversibly damaged upon exposure to high levels of ROS. Aging is accompanied by oxidative stress, and oxygen-rich tissues such as the eye are particularly vulnerable because of its high energy demand and generation of ROS byproducts, which increases the risk for ocular disease. In this study, we profiled the redox proteome of the aging Drosophila eye to identify cysteine residues that are modified by age-associated ROS.