Der Effekt UV-blockierender Kontaktlinsen bei der Therapie der Keratitis superficialis chronica des Hundes

Objective Canine chronic superficial keratitis (CSK) is chronic, progressive keratopathy, which is suspected to be caused by an immune mediated response triggered by ultraviolet light exposure. The purpose of this study was to evaluate the effect of UV-blocking soft contact lenses in treatment for CSK. Methods 26 dogs (26 eyes) with CSK were treated continuously with UV-blocking contact lenses (*Acri.Pat®-UV bandage lenses) for six months. A contact lens was placed on one eye of each dog; the other eye remained without a lens as a control eye. Then, five dogs were treated further on wearing now contact lenses on either eye. Continuously, all patients were treated topically with cyclosporine A on both eyes. The contact lenses were changed every four weeks and an ophthalmic examination was performed at each appointment. Evaluation criteria included corneal alterations as pigmentation, edema, pannus and vascularisation based on digital photographs and drawings. To determine the transmittance characteristics of the contact lenses before and after use, 32 contact lenses were measured with a UV-vis-NIR spectrophotometer. Results Pigmentation increased in eyes wearing contact lenses and in control eyes over the evaluation period of six months. Corneal edema increased in the eyes wearing lenses, but remained unaffected in the control eyes. A significant difference in the incidence of pannus and the extent of corneal vascularisation could not be evaluated. Side effects were noted in six cases (corneal edema and vascularisation, conjunctivitis, blepharospasm). All new lenses studied reduced UV-radiation to a safe level, whereas used lenses did not maintain their transmittance characteristics. Conclusion Extended wear of UV-blocking contact lenses is an ineffective treatment for canine CSK and bears the risk of severe side effects