Effect of Topical Cyclosporine on Dendritic Cell Density in Patients with Dry Eye Syndrome Using In Vivo Confocal Microscopy

Abstract

Background: Dry Eye Syndrome (DES) is a multifactorial disorder of the ocular surface, characterized by inadequate moisture and subsequent discomfort, pain, or visual disturbances. DES is associated with increased corneal dendritic cell (DC) density, a marker of inflammation. Treatments proposed to decrease inflammation in DES currently lack quantitative evidence. This study investigated the effects of cyclosporine eye drops on corneal DC density using in vivo confocal microscopy (IVCM). Our hypothesis is that topical cyclosporine treatment will reduce inflammation as demonstrated by decreased DC density. Methods: In this prospective study, central cornea images for DES patients were obtained with IVCM (HRT III RCM). Images were taken prior to and three months after treatment with either cyclosporine 0.05% or 0.09% twice daily in both eyes. A semi-automated cell count software was used to analyze dendritic cells (DCs) in the sub-basal nerve plexus. A student t-test was conducted to compare DC density before and after treatment. Results: 20 eyes of 10 patients (7 women; mean age 56 ± 22 years) completed the study. 16 eyes and 4 eyes were treated with cyclosporine 0.05% and 0.09% respectively. One eye was excluded due to poor image quality. Mean DC density was 64.63 ± 81.48 cells/mm2 at baseline and 50.36 ± 61.86 cells/mm2 after three months of treatment. There was an average DC density decrease of 14.26 ± 44.95 cells/mm2 after treatment. 12 eyes showed decreased corneal DC density and 7 eyes showed either no detectable change or increased DC density. For eyes treated with cyclosporine 0.05% and 0.09%, the mean difference between baseline and post-intervention was a non-statistically significant decrease of 3.00 ± 25.56 cells/mm2 (p=0.92) and 56.50 ± 77.87 cells/mm2 (p=0.24) respectively. Conclusion: Topical cyclosporine is known to be effective in treating DES, but its microstructural effects on ocular surface inflammation have not been quantified. In this study, IVCM was used to quantify cyclosporine’s effects on reducing corneal DC density in dry eyes. Further investigation is necessary to elucidate this potentially dose-related effect.