Experimental orbital myositis: Evaluation of therapeutic modalities

Abstract

In an animal model of orbital myositis, 47 eyes of 47 male New Zealand white rabbits were treated with orbital photon irradiation, systemic cyclophosphamide, systemic and periocular 5-fluorouracil, systemic and periocular cyclosporine A, and systemic hydrocortisone to evaluate their effect on extraocular muscle fibrosis and restriction. All dosages of photon irradiation lowered early strain gauge measurements but late results were optimal with 20 Gy (Gray). No significant improvement in late strain gauge measurements was gained using systemic corticosteroids or cyclophosphamide. Systemic cyclosporine A produced significant late strain gauge measurement reduction. Periocular cyclosporine A and 5-fluorouracil both produced increased fibrosis and restriction in this model.

Key Words:

• thyroid ophthalmopathy
• orbital myositis
• phorbol ester
• radiation therapy
• cyclophosphamide
• cyclosporine A
• corticosteroids
• fibrosis