This paper analyzes the cost-effectiveness of screening and treating diabetic retinopathy (DR) by simulating the disease progress continuously with existing data. A new computer simulation based on Monte Carlo techniques and logistic transformation follows cohorts from diabetes onset until death in five care scenarios. For younger-onset patients, ophthalmic care reduces the prevalence of blindness by 52% or greater while savings in disability facilities and production losses surpass direct costs. For older-onset patients, less favorable results appear. Financial benefits surpass costs for juvenile-onset patients. For other patients, the net costs of ophthalmic care seem lower than in other health care programs.