Abstract
Purpose: :
To identify the effects of low dose orbital radiation on active thyroid eye disease.
Methods: :
Retrospective chart review of 38 patients with active thyroid eye disease, between the ages of 18 and 70, who underwent low dose orbital radiation. Patients were excluded if their disease was classified as non-progressive and inactive based on the clinical activity score (CAS). Patients were excluded if they had received oral steroids prior to or during their clinical evaluation at the Dean A. McGee Eye Institute. The clinical activity score (CAS), used to characterize the severity of the thyroid eye disease, was determined at time zero (T0), 12 weeks post radiation (T12), and 24 weeks post radiation therapy (T24). Patients who underwent surgery for strabismus, eyelid retraction or orbital decompression between T0 and T12 were excluded. No patients were identified as having compressive optic neuropathy during the retrospective review. The change in CAS post radiation was examined for statistical significance using the standard t-test.
Results: :
The average CAS at TO= 3.3, T12=1.57, T24=1.94 . There was a statistically significant difference comparing the CAS at time T0 to T12 (p<0.001) and T0 to T24 (p<0.001). There was no statistical difference noted between times T12 and T24. The increase in CAS from T12 to T24 is reflective of 3 patients whose CAS increased from T12 to T24 and the smaller sample size of patients included in the T24 data (n=19). Patients who underwent surgery for either restrictive strabismus, eyelid retraction or orbital decompression were excluded in the 24 week data due to the difficulty in accurately assigning a CAS to these patients.
Conclusions: :
Low dose orbital radiation is effective in decreasing the clinical activity score in patients with active thyroid eye disease.
Keywords: radiation therapy • orbit • inflammation