An ophthalmologist is a medical doctor who specializes in treating eyes and vision. Unlike an optometrist, who checks your vision and prescribes glasses, an ophthalmologist has gone to medical school and can perform eye surgery, diagnose eye diseases, and treat serious problems like cataracts, glaucoma, or injuries to the eye.

If you ever need surgery to fix a lazy eye, remove a cataract (a clouding of the eye's lens), or treat an infection deep inside your eye, you'd see an ophthalmologist. They're the most highly trained eye specialists. Many ophthalmologists focus on specific parts of the eye or particular conditions, like retinal specialists who treat the back of the eye, or pediatric ophthalmologists who work specifically with children.

When you get your vision checked for glasses at the mall or a vision center, you're seeing an optometrist. But if something is seriously wrong with your eyes, you'll likely need an ophthalmologist's expertise and training.