PURPOSE: To determine the use of eye care services by type of provider (ophthalmologist, optometrist, and non-ophthalmologist physician) in the Medicare population. METHODS: As a basis for characterizing eye conditions and ophthalmic services among a population 65 years of age and older, 1991 claims from a representative 5% sample of Medicare beneficiaries were analyzed using a previously described classification scheme. Analysis was specifically conducted by type of provider as well as by the service provided. RESULTS: Almost one half of the approximately 30 million Medicare beneficiaries 65 years of age or older received eye care services in 1991, resulting in more than 35,000,000 visits (claims). Ophthalmologists provided services to 71% of this eye care population, and optometrists to 22%; 36% of this population received ophthalmic-related services from other providers, and 14% from only other providers (commonly for eye lid dermatitis and tumors). Cataract was the most common condition, accounting for 41% of visits to ophthalmologists (and 1.2 million cases of surgery), glaucoma accounted for 19% of visits, and retinal diseases for 14%. The visit percentages for optometrists are 58%, 8%, and 11%, respectively. Ophthalmic examination and evaluation accounted for 63% of the 28,000,000 paid ophthalmologists' procedures, and 58% of the 5,500,000 optometrists' procedures. CONCLUSION: Optometrists and physicians other than ophthalmologists were the sole providers of ophthalmic-related services to a large percentage of beneficiaries who received eye care in 1991. Within the universe of service provided by ophthalmologists, the majority of all care consisted of evaluation and management services as opposed to surgical procedure-based care.