Prevalence of dry eye disease in autoimmune thyroid disease and the association of dry eye with clinical signs of thyroid associated ophthalmopathy: observational, noncomparative, cross-sectional study

Background: Autoimmune thyroid disease (AITD) is a risk factor for dry eye disease. The prevalence of dry eye in AITD is not definitely known. Objectives: To determine the prevalence of dry eye in AITD and its association with clinical signs of thyroid associated ophthalmopathy (TAO). Methods: We enrolled a cross-section of 92 patients with AITD between May 1 and August 31, 2013. All were examined to establish thyroid eye signs, and severity was classified as none, mild, and moderate-severe according to the European Group on Graves' orbitopathy. Dry eye disease was verified using an Ocular Surface Disease Index (OSDI) questionnaire, tear break-up time (TBUT), Schirmer test, and ocular surface fluorescein staining. Features of meibomian glands were inspected. This observational study was registered at www.clinicaltrials.in.th, No. TCTR20130713001. Results: The prevalence of dry eye in AITD was 27% by OSDI questionnaire (95% confidence interval (CI), 16%-34%); 96% (95% CI, 93%-99%) by TBUT; 69% (95% CI, 62%-75%) by ocular surface staining; and 18% (95% CI, 12%-23%) using a Schirmer test, which associated dry eye and proptosis with an odds ratio (OR) of 9.3 (95% CI, 1.2-70.6, P = 0.031), and lagophthalmos by ocular surface staining with an OR of 5.8 (95% CI, 1.2-27.7, P = 0.026). Dry eye in patients with or without clinical signs of TAO was not significantly different. Conclusions: The prevalence of dry eye varied by criteria, but was not different in AITD patients with or without TAO. Proptosis and lagophthalmos were associated more strongly with dry eye disease in AITD with TAO, than without.