Association of thyroid dysfunction with ocular surface damage in thyroid dysfunction patients without thyroid ophthalmopathy

Background

It is determined that the patients with thyroid-associated ophthalmopathy (TAO) often occur dry-eye related symptoms due to increasing tear evaporation caused by exophthalmos.However, more than half of thyroid dysfunction patients without TAO appear ocular surface inflammation.It is very important for us to understand the association of thyroid dysfunction patients without TAO with ocular damage.

Objective

This study was to observe the ocular surface changes in thyroid dysfunction patients without TAO.

Methods

A prospective cohort study was performed.Thirty-one patients who were initially diagnosed as thyroid dysfunction without TAO were included in the Second Hospital of Tianjin Medical University from January 2015 to May 2016 as the thyroid dysfunction group, and 16 helthy subjects were simutenniously selected as the control group under the informed consent of all the individuals.The peripheral blood was collected to detect the thyroid function-related indexes.Then the patients with thyroid dysfunction were divided into thyroid stimulating hormone (TSH) reduced group (18 patients) versus TSH elevated group (13 patients) and thyrotrophin receptor antibody (TRAb)⁺ group (20 patients) versus TRAb^– group (11 patients). Exophthalmos degree, Schirmer Ⅰtest (SⅠt), tear film break-up time (BUT), fluorescent integral, ocular surface disease index (OSDI) and corneal inflammation index were examined and intergrouply compared.The correlations of thyroid function indexes with ocular surface examination

results

were analyzed. Results There were no significant differences in exophthalmos degree and SⅠt values between thyroid dysfunction group and control group (t=0.037, P=0.971; t=0.815, P=0.419). The BUT values were (7.74±1.45)seconds and (10.56±1.40)seconds, fluorescent integral scores were 5.00 (1.50) and 2.50 (2.38), OSDI scores were 45.58±9.23 and 19.47±6.25, and corneal inflammation index scores were 0.11 (0.22) and 0.00 (0.06) in the thyroid dysfunction group and the control group, respectively, showing significant differences between the two groups (all at P<0.01). There were not significant differences in exophthalmos degree, SⅠt, BUT and corneal inflammation index scores between the TSH elevated group and TSH reduced group (t=0.473, P=0.640; t=0.650, P=0.521; t=1.634, P=0.113; Z=0.270, P=0.787). The fluorescent integral scores were 4.00 (2.00) and 5.00 (1.00), and OSDI scores were 40.08±9.91 and 47.11±9.75 in the TSH elevated group and TSH reduced group, repectively, with statistically significant differences between these two groups (all at P<0.01). The exophthalmos degrees, SⅠt, BUT and corneal inflammation index scores were not considerably different between TRAb^– group and TRAb⁺ group (all at P>0.05); and significant differences were seen in fluorescent integral scores (4.00[1.50]vs.5.50[1.50]) and OSDI scores ([39.18±6.25]vs.[46.78±8.76]). Corneal inflammation index scores were positive correlated with serum TSH (R²=0.520, P=0.000), and fluorescent integral scores, OSDI scores and corneal inflammation index scores were positive correlated with serum TRAb (R²=0.587, P=0.000; R²=0.329, P=0.024; R²=0.400, P=0.005).

Conclusions

Thyroid dysfunction patients without TAO have ocular surface dysfunction, which probably is associated with abnormal serum TSH and TRAb.

Thyroid dysfunction; Thyroid associated ophthalmopathy; Ocular surface; Thyroid stimulating hormone; Thyrotrophin receptor antibody