Measurement Method of Eyelid Pressure Distribution Using Thin Film Coating on Contact Lenses - 3rd Report: Safety Evaluation and Scratch Mark Formation by Animal Experiments

Eyelid pressure distribution is visualized as a 2D chart of abrasive mark using a sucrose film coated contact lens and an image analysis system. The lens was attached in a rabbit eye for a short time from I to 2 min, and the abrasive mark can be observed by comparing two images taken before and after the experiment. The lens was fabricated by a lamination of a mold casted sucrose and a spin-coated PDMS lens. In order to minimize rabbit's stress caused by wearing the lens, as well as a shorter measurement time, experimental conditions are explored on tear volume for lens lubrication, waiting time before blink, number of blink and blink period. Finally, abrasive charts were obtained by manually assisted eye blink, and they are interpreted as a 2D eyelid pressure distribution chart. A maximum thickness decrease of 0.5mm has been obtained for a blink number of 20 and a blink period of 3s. Biocompatibility and health disorders due to the sucrose lens were also evaluated for 7 month, resulting in no health damages. © 2023 Japan Society for Precision Engineering. All rights reserved.