Anatomy of the Eye The structures of the eye include the cornea, iris, pupil, macula, retina, and the optic nerve. Eye Care Specialists An ophthalmologist is either a medical doctor (M.D.) or an osteopathic physician (D.O.). An optometrist is a doctor of optometry (O.D.) but is not a medical doctor. An optician is a technician who fits eyeglasses. Eye Examinations During an eye exam, an eye doctor reviews your medical history and completes a series of tests to determine the health of your eyes. Eyeglasses and Contact Lenses Eyeglasses are the most common form of eyewear used to correct or improve many types of vision problems. Contact lenses are worn directly on the cornea of the eye. Aging Eyes and Glasses As your eyes age, their lenses become less flexible, and they slowly lose their ability to focus. It's an ongoing, lifelong process called presbyopia, which you begin to notice between ages 40 and 45. Low-Vision Devices Low-vision devices are categorized as either optical or nonoptical. Optical devices are magnifying lenses or closed circuit TV. Nonoptical devices are large-print books and talking computers. Common Eye Disorders One common eye disorder is conjunctivitis, sometimes called pink eye. It's an inflammation of the blood vessels in the eye membrane. Another common disorder is a chalazion—a small bump that develops on the upper or lower eyelid. Age-Related Macular Degeneration (AMD) Age-related macular degeneration is a disease that affects an individual's central vision, making it difficult of read, drive, or perform other daily activities. Why Doctors Remove Cataracts A cataract is a clouding of the eye's lens, a clear, soft structure behind the pupil that works much like a camera lens. The top cause of cataracts is aging. In fact, more people over 70 have cataracts than not. Cataracts and Cataract Surgery A cataract is a clouding or opaque area over the lens of the eye—an area that's normally transparent. As less light reaches the retina, it becomes increasingly harder to see and vision may become dull and blurry. Diabetic Retinopathy Diabetic retinopathy is the most common eye disease in people with diabetes and a leading cause of blindness in the United States. If you have diabetes, you can reduce your risk for this disorder by keeping your blood sugar levels under tight control. Glaucoma Glaucoma is a condition in which the normal fluid pressure inside the eyes slowly rises because the fluid aqueous humor is not able to drain properly. This pressure damages the optic nerve. Refractive Errors Astigmatism is one type of refractive error. It's a condition in which an abnormal curvature of the cornea can cause two focal points to fall in two different locations—making objects up close and at a distance appear blurry.