I recommend reaching out to the schools you are considering because some are stricter about having an optometrist's letter of rec., whereas some are more lenient. I would personally shadow an optometrist regardless of what those schools say to strengthen your application. Although ophthalmology and optometry are similar, you are applying to an optometry school, so it'd make sense to have some experience in this specific field. If you have your own optometrist, definitely ask if you can shadow for a week or two to get the experience; or I would ask your ophthalmologist if they have a recommended optometrist in mind.