For years, radiation therapy to the eye has been used to treat eye problems associated with the thyroid condition Graves' disease. Now a new study questions whether this treatment is actually useful.

Graves' disease triggers an overproduction of hormones from the body's thyroid gland, a key regulator of metabolism and other vital functions. A small percentage of people with the disorder have a complication called Graves' ophthalmopathy, which is characterized by bulging eyes, double vision and other eye problems.

To investigate the effectiveness of radiotherapy for these eye complications, investigators studied 42 patients with Graves' ophthalmopathy. The patients exhibited a variety of symptoms including higher-than-normal volumes of eye muscle and fat, bulging of the eyes, less eye range of motion and double vision.

The patients received radiotherapy in one eye and a "sham" treatment in the other eye.

At follow-up, 3 and 6 months after treatment, no significant differences were observed between the treated and untreated eyes.

And this was true regardless of whether a patient was a smoker. Smokers, the researchers note, have been found to be more vulnerable to Graves' ophthalmopathy, and this could theoretically affect their response to treatment.

Graves' disease is a naturally remitting condition, and over a period of time many of the symptoms, including [those related to] the eyes, may improve. This tendency to natural remission, together with the imprecision of measurements used in most previous studies, has allowed the perception to persist that the treatment is effective.

Overall, in 44% of the patients, the eye treated with radiotherapy did not appear any different from the non-treated eye. In about 27% of patients the treated eye appeared better than the untreated eye, but in 30% it appeared worse.

Ophthalmology September 2001;108:1523-1534