What's the main difference between an ophthalmologist and an optometrist? I just know that an ophthalmologist is a md. If I was recently diagnosed with hyperthyroidism (with graves disease being the likely cause), which one am I suppose to see? My eyes

In . In this case it makes sense to see an ophthalmologist who is an md and is trained in both the medical and surgical treatment of eye diseases. In your case, may may need to see a subspecialist known as an oculo-plastic specialist.
While . While the optometrist takes care of one's vision by use of glasses and contact lenses, only the ophthalmologist can perform any surgery on your eyes. The person who made the diagnosis of hyperthyroidism can also refer you to the appropriate ophthalmologist for further evaluation and treatment. More importantly, any time you need/want a referral to a specialist, i would suggest turning to your family physician for his/her input since they probably work with all the specialists in your area. Ask who they would see if they had the same condition or who they would send their family members to see. Short of that, you can blindly search online for specialty association members in your area. Remember that not all specialties, associations, and boards are recognized. That's why i always suggest going to see your family physician. Good luck!
Ophthalmologists . Ophthalmologists are medical doctors, having attended medical school after college, and then completing a 4 year residency training in a hospital. We are trained to make the proper diagnosis and to treat medical and surgical diseases of the eye. Optometry is generally a 4 year college experience. While many optometrists have gained training to deal with these issues, most of the time they need to refer their patients to medical doctors for treatment.