Experimental cataract models produced by repeated blunt mechanical stimulation and elucidation of the pathogenetic mechanism

PURPOSE: The pathogenesis of cataract produced by mechanical stimulation of the eye was studied using experimental models. METHODS: The eyes of rabbits (in vivo) and the extracted lenses of rats (in vitro) were subjected to vibration from an electric massage machine and tapping. The histological changes, aqueous flare score, protein and prostaglandin (PG) E2 levels in aqueous humor, and the rate of vitreous liquefaction were measured, and the involvement of apoptosis was examined in the rabbit model. RESULTS: In both models, mechanical stimulation resulted in a high frequency of opacification of the lens in the anterior or posterior subcapsular region. In the in vivo model, histopathological examination revealed vacuolar changes in the lens epithelium and swelling of lens fibers. Increases in aqueous flare score, protein level, PGE2 level, and the rate of vitreous liquefaction were confirmed. The involvement of apoptosis was not proven. CONCLUSION: Repeated mechanical stimulation of the eye produced lens opacification. In patients with atopic dermatitis, mechanical stimulation such as a habit of eye tapping may be the cause of or a factor in promoting cataract development.