Autoimmune Disorders

Abstract

In select cases, external beam radiation to the retrobulbar tissues and eye muscles produces reduction of signs and symptoms associated with autoimmune eye disease. Doses used commonly are 20 Gy in 10 fractions of 200 cGy calculated to the midplane for bilateral cases. Soft tissue findings, corneal involvement, and visual acuity impairment are most likely to respond well, although improved ocular mobility and reduction in proptosis may occur in >50% of cases. Treatment, whether unilateral or bilateral, requires simulation, treatment planning, dose calculation, and care in not exceeding tolerance levels. Treatment with IMRT is also now an option. Complications from correctly administered radiation therapy are rare, although cases of radiation retinopathy have been reported when large daily fraction sizes were inadvertently administered. Cases should be selected with care, with consultation with ophthalmologists and endocrinologists, as all patients with thyroid eye disease are not candidates for radiotherapy. The implementation of secondary therapeutics has increased the number of therapeutic options, but radiotherapy is still prescribed in moderate-to-severe Graves’ orbitopathy especially if IV corticosteroids are contraindicated or ineffective. The role of radiation continues to be the object of prospective clinical investigation (NCT02339142, NCT03098225).