AOA 2025: In vitro antioxidant effects of dry eye formulation on human corneal epithelial cells

Over-the-counter drops for dry eye may help reduce oxidative stress and maintain the ocular surface homeostasis.

(Image credit: ©Gevorg Simonyan—stock.adobe.com)

Cecelia Koetting, OD, and investigators reported that Blink Nourish Eye Drops (Bausch + Lomb) exerted antioxidant effects on human corneal epithelial cells in an in vitro cell model. She reported the results at the Annual Meeting of the 2025 American Optometric Associations Congress in Minneapolis, Minnesota. She is from the University of Colorado School of Medicine, Aurora, Colorado.

Oxidative stress, she explained, plays a key role in the pathogenesis of dry eye disease. Specifically, high levels of reactive oxygen species (ROS), lipid oxidative stress markers, and inflammatory cells have been reported in the conjunctiva and tear film of patients with Sjogren syndrome.¹

Over-the-counter drops for dry eye may help reduce oxidative stress and maintain the ocular surface homeostasis.

She and her colleagues conducted an in vitro study to evaluate the formulation’s effects on human corneal epithelial cells compared with two other over-the-counter dry eye drops (Refresh Relieva, Allergan; Systane Hydration, Alcon).

The cells were maintained in medium with a dry eye drop for 30 minutes and then exposed to CellRox green (CRG) reagent for 30 minutes; CRG is a fluorogenic dye used to detect ROS, a key indicator of oxidative stress in live cells. The CRG medium was removed and the cells were exposed to 0.003% or 0.006% hydrogen peroxide and a dry eye drop. The changes in the CRG were measured every 15 minutes for 2 hours.

Effect on cells exposed to hydrogen peroxide

Koetting reported that Blink Nourish demonstrated antioxidant activity by protecting the cell metabolic activity and significantly reducing oxidation of CRG after exposure to 0.003% hydrogen peroxide.

Five cell scenarios were evaluated: no exposure to hydrogen peroxide, exposure to 0.003% hydrogen peroxide, and exposure to hydrogen peroxide in the presence of each of the 3 formulations of dry eye drops.

Regarding the metabolic activity of the cells, Blink Nourish protected the cell metabolic activity and significantly reduced the oxidation of CRG (measured by relative fluorescent units) following stimulation with 0.003% hydrogen peroxide. “The results of Blink Nourish did not differ significantly from the cells not exposed to hydrogen peroxide, indicating more of a protective effect from a component in the Blink Nourish formulation,” she said. The cell groups exposed to the other two formulations tested had significantly lower metabolic activity.

The area under the curve (AUC) of CRG fluorescence showed that Blink Nourish had a significantly lower AUC compared with the other two formulations evaluated, again suggesting that a component of Blink Nourish had an antioxidant effect.

In the evaluation of the effect of exposure of cells to the 0.006% hydrogen peroxide, all groups had significantly reduced metabolic activity. As previously, the AUC was significantly lower with Blink Nourish compared with the other formulations. The Blink Nourish group was the only formulation that was did not have significantly greater damage compared with the control. “Overall, the Blink Nourish drop demonstrated antioxidant activity by protecting the cell metabolic activity and significantly reducing the oxidation of CRG after exposure to 0.006% hydrogen peroxide,” Koetting said.

She concluded, “The results indicated that the antioxidant effects of Blink Nourish eye drops with human corneal epithelial cells compared with other dry eye products in this in vitro cell model. The Blink Nourish formulation exhibited antioxidant activity and demonstrated the potential to main the homeostasis of the ocular surface environment.

Reference

Wakamatsu TH, Dogru M, Matsumoto Y, et al. Evaluation of lipid oxidative stress status in Sjogren syndrome patients. Invest Ophthalmol Vis Sci. 2013;54:201-10. doi:https://doi.org/10.1167/iovs.12-10325.