There are a limited number of case reports confirming the radioiodine (I-131) presence in tears and only a few case reports of lacrimal gland dysfunction after I-131 therapy. This study was designed to clarify whether lacrimal gland function can be affected by I-131 therapy.
We studied 100 eyes of 50 patients who had received high doses of I-131 for treatment of differentiated thyroid carcinoma and 100 eyes of 50 age- and sex-matched control individuals without a history of interfering conditions. The exposed group was studied at least 3 months after their last I-131 therapy. Dry eye symptoms and Schirmer test values (wetting level in millimeters per 5 minutes) of an exposed group were compared with those of an unexposed group.
Fifty-one percent of the exposed eyes and 50% of the unexposed ones revealed at least 1 of the dry eye symptoms. There was no significant difference in symptoms between 2 groups, except for burning sensation and eye redness, which were significantly higher in the exposed eyes. A lower Schirmer test value was noted in the exposed group, 14.5 ± 10.8 mm, when compared with that in controls, 18.2 ± 11.0 mm (P = 0.016), and the relative risk of an abnormal Schirmer test in exposed cases to control group was 1.78 ± 0.62. Correlation coefficient analysis showed no significant relationship between Schirmer test values and cumulative doses of administered I-131.
Reduction in the tear secretion from lacrimal glands is seen after high-dose I-131 therapy; however, their symptoms are no greater than an unexposed population.
From the Research Institute for Nuclear Medicine, Medical Sciences/University of Tehran, Shariati Hospital, Tehran, Iran.
Received for publication March 3, 2007; revision accepted May 23, 2007.
Supported by the Medical Sciences/University of Tehran (grant no. 2021).
Reprints: Babak Fallahi, MD, Research Institute for Nuclear Medicine, Shariati Hospital, Kargar Shomali Ave., PC 14114, Tehran, Iran. E-mail: firstname.lastname@example.org.