Purpose: Exposure to solar ultraviolet (UV) radiation is believed to increase oxidative stress and may cause oxidative damage to retinal pigment epithelial (RPE) cells. UV light triggers a number of deleterious cellular responses in retinal cells that lead to changes in gene and protein expression. Lutein and zeaxanthin isomers—RRand RS-zeaxanthin—(L/Zi) are carotenoids that play a functional role in the macula and retina of the eye. Optimal levels of L/Zi may reduce the risk of macular degeneration, due in large part to their antioxidant properties and ability to absorb light within the UV range. This study is to evaluate soluble macular carotenoids’ (Lutemax ® 2020) effect on cholinesterase activity, antioxidant enzymes and in response to UV irradiation in an in vitro model. Methods: Retinal pigment epithelial (RPE) cells play a key protective role by shielding the retina from damaging UV rays, and are used as a model to study the effect of therapeutic interventions. In this study, a human RPE cell line [ARPE-19 cells were acquired from ATCC (CRL-2302)] was either mock treated or given L/Zi (Lutemax ®