Changes in conjunctival cytology and tear function tests with radioiodine treatment for hyperthyroidism.

Objectives: Radioiodine (RAI) is used in the treatment of hyperthyroidism and differentiated thyroid cancer. Radioiodine therapy is associated with dry eyes and some side effects are seen especially due to beta rays. In this study, the functional and cytological status of lacrimal glands after RAI therapy was evaluated.

Methods: Twenty-five patients with a mean age of 55.16 years with planned low-dose RAI therapy were evaluated. Just before and 6 months after the treatment, the lacrimal glands were evaluated with tear break-up time (BUT), Schirmer's test, impression cytology and "Ocular Surface Disease Index (OSDI)" questionnaire.

Results: The mean value of Schirmer's test was 16.20 ± 3.61 pre-treatment and 11.28 ± 4.39 post-treatment for the right eye, and 15.76 ± 3.27 and 10.60 ± 4.42 for the left eye, respectively. The mean value of Schirmer's test decreased significantly post-treatment in both eyes (p = 0.0001). The BUT score also decreased significantly post-treatment (p = 0.001). The mean value of OSDI score was 27.5 ± 8.02 pre-treatment and 46.36 ± 10.27 post-treatment. The mean value of OSDI score increased post-treatment (p = 0.0001). The impression scores also increased post-treatment in both eyes (p = 0.0001).

Conclusion: Even low-dose (≤30 mci) RAI treatment affects lacrimal gland functions. Low-dose RAI causes a decrease in the value of Schirmer's test and the BUT test, and an increase in the value of OSDI score and impression scores.