American Medical Association Family Medical Guide - American Medical Association [724]
Having Your Eyes Examined
If you are having vision problems, talk to your primary care doctor, or go directly to an eye care professional for diagnosis and treatment. The main types of eye care professionals are ophthalmologists (eye MDs), optometrists, and opticians.
Ophthalmologists are medical doctors with specialized training in the diagnosis and treatment of eye diseases and disorders. They perform eye examinations to evaluate vision and check for signs of eye diseases such as cataracts or glaucoma. Ophthalmologists are licensed to prescribe drugs, glasses, and contact lenses. They are also trained and licensed to perform eye surgery.
Optometrists are health professionals who are trained and licensed to diagnose and treat vision problems and to prescribe glasses and contact lenses. Optometrists are not MDs and are not licensed to perform eye surgery. In some states they are licensed to treat some eye diseases and prescribe certain drugs, such as eyedrops.
Opticians are eye care professionals who are trained to make and fit glasses and, sometimes, contact lenses, after they have been prescribed by an ophthalmologist or an optometrist. Opticians do not perform eye examinations.
How Often Should I Have My Eyes Examined?
To protect your vision, you should have regular eye examinations performed by an ophthalmologist every few years. If you are over age 40, your eyes should be examined every 2 years or as often as your doctor recommends. Some serious eye diseases, such as some types of glaucoma, produce no symptoms in the early stages and can be detected only by an eye examination. For this reason, regular eye examinations are essential for maintaining good vision and eye health.
An Eye Examination
Before performing a thorough eye examination, an ophthalmologist asks you about your health history and your family’s health history, and asks you to describe any vision problems you may be having. The examination itself usually consists of the following painless evaluations and tests:
• Visual acuity test To test the acuity (sharpness) of your vision, the doctor asks you to read the rows of letters on an eye chart. The letters on the eye chart are of a standard, decreasing size, and the chart is set at a standard distance of 20 feet. To take the test, one eye is covered and you read as far down the chart as possible; then the other eye is covered and you read down the chart again. The results of a visual acuity test are given as two numbers (for example, 20/40). The first number refers to the distance at which you read the letters—20 feet. The second number refers to the distance at which a person with normal vision can read the smallest letters that you were able to read correctly at 20 feet. For example, the result 20/40 means that you were able to read letters at 20 feet that a person with normal vision would be able to read at 40 feet. Visual acuity may be different for each eye. Difficulty reading the chart may indicate a focusing disorder, usually nearsightedness (see page 1030) or farsightedness (see page 1032). It could also be a sign of a serious eye disease such as macular degeneration (see page 1046).
• Outer eye examination The doctor examines the appearance of the outer eye, including the eyelids, eyelashes, and orbits (the bony sockets in the skull that contain the eyeballs), and the surface of the eyeball, including the conjunctiva and sclera. He or she may direct a light toward and away from each eye to determine if the pupils open and close properly. To evaluate your eye muscles and the alignment of your eyes, the doctor asks you to focus on and follow a moving object, such as his or her finger. The ophthalmologist will also use a slit lamp (a powerful microscope that shines a bright light into your eye) to examine the front of the eye, including the cornea, anterior chamber, iris,