Contact Lenses Image
The lens is specifically designed to prevent contact lens-induced dry eye (CLIDE) (Credit: Terasaki Institute for Biomedical Innovation)

A contact lens prototype has been specifically designed to prevent contact lens-induced dry eye (CLIDE). The lens alleviates this condition by facilitating tear flow in response to normal eye blinking. This approach can relieve the discomfort, visual impairment, and risk of inflammation experienced by millions of contact lens users suffering from CLIDE.

The approach uses a contact lens design that incorporates microchannels to facilitate tear flow movement and flow so that dry eye can be avoided. This flow can be achieved by pressure applied by normal eye blinking so that no external devices are needed.

In fabricating their contact lens prototype, the team utilized a time-saving method — their lens mold was made from a silicone polymer mixture; this allowed for easy removal of the lens cast on it by gently bending the mold. Previous methods necessitated a twelve-hour soak in hot water to remove the lens. The approach resulted in high-quality, smooth microchannels, as well as lenses that could be thirty times thinner than previous lenses. A custom device was used to fabricate reservoirs at the ends of each microchannel for the inflow and outflow of liquids.

After various experiments, a configuration that proved effective was microchannels with square cross-sections arrayed in a novel circular pattern on the lens surface; this was compatible with the function and curvature of the lens and allowed for optimum liquid flow.

The team demonstrated a proof-of-concept validation of their lens’ ability to guide tear flow originating from the lens surface to the underside of the lens to combat dry eye syndrome. The team quantified these flows and established that the flows were driven by low-pressure levels like those from normal eye blinking. Further tests could be devised to test these lenses on animal models and in patients.