Effects of 0.05% cyclosporine A eye drops on ocular surface microbiome in patients with mild to moderate dry eye syndrome

Purpose: To evaluate the effects of topical use of 0.05% cyclosporine A eye drops for three months on ocular surface microbiome in patients with mild to moderate dry eye syndrome. Methods In this study, 14 patients(28 eyes) diagnosed with dry eye syndrome were enrolled. All patients used 0.05% cyclosporine A eye drops twice a day combined with 0.3% sodium hyaluronate eye drops four times a day for three consecutive months. The ocular surface parameters and tear samples were detected before using the medication, and six weeks, three months after using the medication. The results were recorded as V1, V2 and V3, respectively. The test indexes included the scores of the Chinese Dry Eye Questionnaire, Schirmer's Ⅰ test, inferior corneal staining scores (ICSS), fluorescein staining tear film breaking time (FBUT), noninvasive tear breakup time-average (NITBUT-av), tear meniscus height (TMH) and ocular redness index (ORI). Also, the differences of ocular surface microbiome between V1 and V3 were compared by the 16S rRNA gene sequencing technology. Results Two of the ocular surface parameters were significantly improved after three months of treatment, which were FBUT (P V1−V2 =0.017, P V1−V3 =0.001) and ICSS (P V1−V2 =0.036, P V1−V3 =0.001). However, CDEQ, Schirmer's Ⅰtest, TMH, NTBUT-av and ORI showed no statistical significance in our study. We analyzed the samples by the 16s RNA gene sequencing technology, and the results suggested that the analysis of the alpha diversity, beta diversity and bacteria abundance revealed no significant difference between V1 and V3. Conclusion Topical application of 0.05% cyclosporine A eye drops twice a day combined with 0.3% sodium hyaluronate eye drops four times a day can relieve the symptoms and signs of patients with dry eye syndrome. However, it showed little effect on the microbiome of ocular surface over the course of our study. Trial registration This study was also registered in Chinese Clinical Trials Registry (ChiCTR2100042465) On 22/01/2021.