An atypical case of microcysts associated with silicone hydrogel contact lens: findings on in vivo confocal laser microscopy.

To report a case of microcysts in the cornea of a female who wore silicone hydrogel contact lenses (CLs) including observation by an in vivo confocal laser microscope. A 31-year-old woman who wore Acuvue Oasys CLs was referred to our hospital because of reduced visual acuity, eye pain, and photophobia in both eyes. The patient's history and clinical presentation were reviewed. In vivo investigation was also performed by using HRT II Rostock Cornea Module. Slitlamp microscopy revealed corneal haze and a number of microcysts in both eyes. The cysts were less obvious on fluorescein staining than on corneal observation. Observation with the HRT II Rostock Cornea Module showed a number of irregular oval-shaped cysts in the basal layer of the corneal epithelium. The cysts were much larger than those induced by infection with Acanthamoeba, so the possibility of Acanthamoeba keratitis was ruled out. Based on these findings, treatment with betamethasone phosphate eye drops and levofloxacin eye drops (both five times daily) were started for the microcysts. After about 10 days of treatment, all of the cysts resolved. Microcysts may occur in persons who wear silicone hydrogel CLs caused by inflammatory, mechanical etiology, or a toxic reaction from the solution/lens interaction that the patient was using. In vivo Confocal laser microscope is useful for making a definite diagnosis of microcysts.