Frequency of dry eye syndrome in patients with multiple sclerosis: A cross-sectional case-control study

Demyelination of the nerve fibers of the central nervous system is a main pathology of multiple sclerosis (MS), in which inflammation plays a major role. Studies have shown that inflammation is the leading cause of dry eye disorder. To investigate the association between inflammation and both diseases, we aimed to estimate the prevalence of dry eye syndrome (DES) in MS patients and its correlation with the severity of the disease and disability status.

We enrolled 100 MS patients randomly and 100 healthy controls. DES was evaluated by Dry Eye questionnaire and Scoring System (DESS), tear break-up time (TBUT), tear meniscus height (TMH), and Schirmer 1 & 2 tests in subjects. Furthermore, the leading disability in MS was assessed by a clinician (neurology professor) using the related questionnaire (Expanded Disability Status Scale).

According to the TBUT, THM, and Schirmer tests, the number of subjects with abnormal results was significantly higher in the MS group than in the control group. The severity of DES measured by the DESS was also higher in the MS group compared to control group. Also, there was a significant relationship between increasing disability and abnormal dry eye tests, especially in MS patients with EDSS scores>4.

The present study highlights the importance of considering dry eye disorder in MS patients as a possible consequence of inflammation. Also, our results suggested a significant relationship between dry eye disorder and the EDSS scores.