Objective evaluation of improvement in optic neuropathy following radiation therapy for thyroid eye disease

Purpose: While the literature supports the use of radiation therapy for thy roid eye disease, it does not sufficiently describe in detail the results o f radiation therapy for optic neuropathy associated with thyroid eye diseas e. The objective of this study is to quantify the changes in parameters of optic neuropathy after orbital irradiation for thyroid eye disease. Methods and Materials: Twelve consecutive patients with optic neuropathy fr om thyroid eye disease were followed by a single neuro-ophthalmology practi ce and treated by one radiation oncologist with radiation therapy from 1991 through 1995, All cases were prospectively followed for visual acuity, col or vision, mean deviation, and/or foveal sensitivity and afferent pupillary defect. All patients received 2000 cGy in 10 fractions with megavoltage ir radiation to the orbits. Results: Ten of 12 patients were evaluated for follow-up (one moved out of this country and one had a stroke, which confounded interpretation of exami nation results). An analysis was performed retrospectively while treatment and evaluation remained uniform. Five men and five women formed the basis o f this study with a median age of 60 years (35-76 years). Nineteen eyes wer e evaluated for thyroid optic neuropathy, Improvement in optic nerve functi on occurred in eight of ten patients. Improvement was seen either during ra diotherapy or within 2 weeks of completion. No long-term adverse effects we re noted. Conclusion: This study objectively demonstrates improvement in optic neurop athy from radiation therapy for thyroid eye disease, (C) 2000 Elsevier Scie nce Inc.