Ophthalmologist: a medical practitioner specializing in the diagnosis and treatment of eye diseases. Eye surgeon, full drug prescribing. Mainly diagnose and treat pathology. Can also prescribe glasses They are MDs
Optist: Also called as optometrist. A person who is professionally trained and licensed to examine the eyes for visual defects, diagnose problems or impairments, and prescribe corrective lenses or provide other types of treatment.
An ophthalmologist get specialized training in ophthalmology, so they are able to do surgery and prescribe medicine.They often treat eye diseases. While an optometrist can only prescribe glasses and contacts. That is to say, they often treat vision problem.