Selenium in Mild Thyroid Eye Disease in North America

Thyroid eye disease (TED) is a disease in which the soft tissues surrounding the eye can
become inflamed, scarred, and at times permanently damaged in an autoimmune reaction highly
associated with abnormal thyroid hormone levels. Some patients have much more severe TED
than others, but overall, most patients reach a point with relatively stable TED after 1 to
2 years. A recent European study showed that oral selenium, a trace mineral involved in
anti-oxidation and immune regulation, could actually alter the course of mild TED, lessening
its signs and symptoms and even improving the quality of life of those who took it. The
investigators would like to perform a sister study throughout North America. In this
randomized, double-blinded, multi-center trial, some subjects with mild TED would be given
100 micrograms of sodium selenite twice a day; others would receive a placebo. Signs,
symptoms, and quality of life would be measured at regular intervals throughout the 6 month
period of drug administration, and for 6 months thereafter.

Inclusion Criteria:

- Age 18 or older

- Able to provide informed consent

- Able to swallow pills

- Mild thyroid eye disease requiring no past treatment other than ophthalmic drops or
ointment

- Euthyroid: at least 2 months if on medication irregardless of thyroidectomy status;
at least 6 months after radioiodine therapy; if euthyroid for the year prior to
enrollment, needs normal thyroid-stimulating hormone (TSH) within last 3 months; if
uncontrolled for the year prior to enrollment, needs normal TSH and free T4 within
last 3 months; if TSH low, needs normal T3 and free T4

Exclusion Criteria:

- Moderate or severe thyroid eye disease (based upon International Thyroid Eye Disease
Society VISA form), including: grade 2 chemosis or lid edema; corneal exposure with
threat of or resulting in perforation; optic neuropathy; grade 3 restriction of any
extraocular muscle

- Double vision (diplopia) in primary or reading positions

- Duration of thyroid eye disease greater than 12 months (as per patient history)

- Drug or alcohol abuse

- Concurrent or past use of selenium during period of thyroid eye disease

- Severe systemic illness (defined by treating physician)

- Pregnant or breastfeeding