Clinical characteristics of dry eye patients with thyroid disorders: a cross-sectional study.

Purpose: To characterize the clinical findings in dry eye disease (DED) patients with thyroid disorders and explore their associations with DED symptoms and signs.

Methods: In this retrospective cross-sectional chart review study, 99 patients who were diagnosed as DED and subjected to thyroid function screening were included. Corneal fluorescein staining (CFS), Schirmer 1 test (S1T), tear meniscus height (TMH), the first noninvasive breakup time (NIBUT-first), the average noninvasive breakup time (NIBUT-avg), and meibomian gland (MG) dropout ratio were tested and their correlations with thyroid function were analyzed.

Results: Overall, the average age and gender distribution of DED patients with or without thyroid disorders were similar (p = 0.391 and 0.804). DED patients with thyroid disorders had shorter NIBUT-first(p < 0.001) and NIBUT-avg( p = 0.0042), and higher MG dropout ratio (p = 0.001). Among thyroid function assessments, elevated levels of anti-thyroid peroxidase antibody (Anti-TPO) and anti-thyroglobulin antibody (Anti-Tg) had significant correlation with reduced NIBUT and increased MG dropout ratio. When either NIBUT-first or MG dropout ratio was used as a predicting factor for thyroid disorders, ROC curve demonstrated a cut-off value of 5.255(NIBUT-first AUC 0.770, sensitivity 85.7%, specificity 58.8%, p < 0.001) and 0.229 (MG dropout ratio AUC 0.784, sensitivity 70.6%, specificity 79.6%, p < 0.001). When combining them together, an AUC area of 0.841(sensitivity 88.2%, specificity 66.2%, p < 0.001) was reached.

Conclusion: Shorter NIBUT and higher MG dropout ratio correlated with abnormally elevated levels of Anti-TPO and Anti-Tg in DED patients. A combination of NIBUT and MG dropout assessment may have diagnostic potential as a predictive biomarker of possible thyroid disorders.