Knowledge Bank

Keratoconus is a disorder characterized by progressive non-inflammatory corneal degeneration that leads to abnormal shape of the cornea which impairs vision. The disease affects about one per two thousand people worldwide. A potential cause of keratoconus is believed to be abnormal eye-rubbing. Previous clinical studies have shown a significant mechanical trauma to the corneal epithelium after rubbing on the eyes in normal human subjects. However, the mechanism by which eye-rubbing could contribute to the development and progression of keratoconus is not well understood. This project aims to study the effects of eye-rubbing on the mechanical properties of the cornea in a canine eye model. Six pairs of dog eyes were collected from a local animal shelter and the simulated eye-rubbing were induced in one eye per pair while the intraocular pressure (IOP) is monitored. Cornea samples were collected after eye-rubbing and tested using a dynamic mechanical analysis (DMA) and ramp test protocols by a Rheometrics System Analyzer (RSA) to compare mechanical responses between rubbed eyes and control eyes. The complex modulus and dynamic viscosity showed a decreased trend in the samples that experienced eye-rubbing as compared to the control samples. These results suggested that the cornea’s ability to resist dynamic loading may be altered after eye-rubbing. The results of this research provided insight into whether corneal biomechanical properties are altered by eye-rubbing which contributes to keratoconus risk.