Free radical production in patients undergoing long-term topical antiglaucoma treatment or contact lens wearers by impression cytology specimens

Purpose: To investigate free radical production in impression cytology spec imens using microplate cold light cytofluorimetry. Methods: 60 impression cytology specimens (IC) were harvested in 30 patient s aged from 20 to 90 years. IC were taken in 10 healthy subjects, 10 glauco ma patients receiving longterm treatment for glaucoma and 10 contact lens w earers for more than five years. A complete ophthalmologic examination (BUT , corneal staining) was performed. Evaluation of free radical production wa s done using a dichlorofluoresceine diacetate (DCFH-DA) test for H2O2 evalu ation and a hydroethidine test for O-2(-) measurement. Results: The BUT values in the two pathological groups were significantly l ower than those of controls (p<0.001). A free radical production was found in both contact lens wearers (p<0.001 compared to control values) and glauc oma patients (p<0.001 compared to control values). Both hydrogen peroxyde a nd superoxide anion productions were significantly correlated to the decrea se of BUT values and the increase of superficial punctuate keratitis. Conclusion: The results of this preliminary study confirm that conjunctival epithelial cells may abnormally produce oxygen free radicals in chronic oc ular surface disorders. This may participate to the cellular alterations ob served in inflammatory diseases of ocular surface.