Scleritis is a severe chronic inflammation of the eye wall. High-dose corticosteroids and other immunosuppressive drugs are often required to control the inflammatory process. With the development of new and potentially more effective treatment modalities for scleritis has emerged the need for an accurate and reproducible system for quantifying the severity of scleritis and evaluating the response of individual patients to treatment. We have developed a quantitative scoring system, based on common clinical signs of scleritis, and evaluated it in 24 patients with scleritis. Our results indicate that this system is simple, rapid, reproducible and useful in grading the severity of scleritis and in predicting the response of patients to systemic immunosuppressive therapy.