Ophthalmology is the branch of medicine focused on eyes. The doctor who gives you an eye exam studied ophthalmology.
There are many branches of medicine, such as psychiatry, cardiology, and podiatry, which focus on the mind, the heart, and the feet, respectively. Ophthalmology is the branch that focuses on the eyes. If you study ophthalmology, you'll learn about different parts of the eye such as the iris and cornea. You'll learn about eye problems, such as cataracts. Doctors who study ophthalmology are called ophthalmologists, and they're the kind of doctor you go to when you need glasses or contacts.