Abstract
Purpose: :
To ascertain if there are any significant differences in tear film osmolarity in patients with Graves' disease when compared to normal controls. Patients with Graves' disease are at risk for developing thyroid eye disease (TED) and subsequent dry eye syndrome (DES)1.
Methods: :
Tear osmolarity was measured using the TearLab osmolarity system in patients with Graves' disease (n=18) and normal controls (n=18). Subjects had not used any eye drops within 2 hours of tear osmolarity testing. Dry eye symptoms were assessed using the Ocular Surface Disease Index (OSDI) and Symptom Assessment in Dry Eye (SANDE). Controls were recruited from ophthalmology clinics with no history of dry eye syndrome (DES) or thyroid dysfunction.
Results: :
The cases and controls were matched with respect to age, gender and race. Of the eighteen patients with Graves disease, 83% had TED associated with proptosis (77%) and/or eyelid retraction (61%). There were differences in the use of artificial tears (n=12, n=2 p=0.002) between cases and controls, respectively. There were no significant differences in the mean number of systemic medications (2.7, and 3.6) between cases and controls, respectively. The mean (± SE) tear osmolarity was similar in Graves' disease patients as compared to controls (305.1 ±2.6, 304.5 ±2.6, p=0.80). Analyzing the eye with the higher osmolarity for each patient rather than the mean osmolarity also revealed no significant difference between groups (313.4 ±2.97 vs. 310.3 ±2.97 p=0.46). Only 3 (16.7%) patients from each group had elevated tear osmolarity (≥315). OSDI and SANDE scores were not correlated with tear osmolarity (Spearman r=-0.12, -0.08 respectively, all p>0.50). There were statistically significant differences between Graves' patients as compared to controls in mean OSDI score (14.3±2.2 vs. 6.33±2.2, p=0.02) and mean SANDE score (52.1 ±5.7 vs. 8.6 ±5.7, p<0.0001).
Conclusions: :
Dry eye symptoms were found to be significantly correlated with the presence of TED. However, in contrast to previous reports, we did not find any significant difference in tear osmolarity between patients with Graves' Disease and normal controls2. One possible explanation is that a higher percentage of Graves' disease patients were using artificial tears and therefore over time may have caused an improvement in their underlying dry eye syndrome. 1. Gürdal C, Saraç O, Genç I, Kirimlioglu H, Takmaz T, Can I. Ocular surface and dry eye in Graves' disease. Curr Eye Res. 2011 Jan;36(1):8-13. 2. Iskeleli G, Karakoc Y, Abdula A. Tear film osmolarity in patients with thyroid ophthalmopathy. Jpn J Ophthalmol. 2008 Jul-Aug;52(4):323-6. Epub 2008 Sep 5.
Keywords: cornea: tears/tear film/dry eye • autoimmune disease