Eye exams are an important part of maintaining good overall eye health. Having regular eye exams is a critical component in detecting eye diseases or problems in their early stages when they are often still treatable. With regular eye exams the doctor can sometimes detect a problem before any noticeable symptoms begin to occur.
Eye exams are necessary to prescribe proper corrective lenses or contacts, but can also serve a more specialized purpose, such as determining eligibility for laser refractive surgery, or monitoring an eye condition. Regular eye exams are the key to preserving good vision for life.
A thorough eye examination consists of a variety of standard tests designed to measure visual acuity and other vision faculties, as well as observe the health of the eye and check for common eye diseases. There is no pain or discomfort associated with an exam, and they typically take less than an hour.
General eye exams can diagnose a variety of eye conditions early on and are the best way to preserve good vision. For children, strabismus (crossed eye) and amblyopia (lazy eye) can often be diagnosed and treated in early childhood, avoiding life-long vision impairment. Also, rare eye conditions from birth (like congenital cataracts) can be diagnosed and treated. For all ages, refraction tests can determine whether prescription eyewear would be beneficial, and what power is necessary. Furthermore, many debilitating eye diseases can be diagnosed before noticeable symptoms occur, potentially making the difference between minor damage and major vision loss.
Eye exams are recommended regularly throughout all phases of one’s life. In the first three years, infants should have their vision checked as part of regular pediatric checkups. Throughout childhood, it is important to have a comprehensive eye exam once a year, as early detection is the best way to prevent vision issues. Into adulthood, the American Optometric Association recommends an eye exam every 2 years, but you should see your eye doctor annually if you notice a change in vision, wear corrective lenses or have a family history of diabetes or glaucoma. Exams may be required more frequently for patients monitoring a diagnosed eye condition, or with a hereditary predisposition to an eye disease.
Common tests and evaluations during an eye exam include:
- Introductory interview: The doctor will ask basic questions about a patient’s medical history and eye health history.
- External examination: The doctor inspects all outward visible parts of the eye and surrounding tissue.
- Pupil inspection: The patient’s pupils will be inspected for equal size and regular shape. Then the doctor tests how they react to light and objects at various distances.
- Eye muscle health and mobility: Eye movement is checked in six directions (corresponding to the six extraocular muscles), as well as tracking a moving object (such as a pen).
- Visual field: The patient covers one eye at a time, and with the other eye gazing straight ahead, identifies objects in peripheral vision (often simply the number of fingers the doctor is showing.)
- Visual acuity: A common means of measuring visual acuity is the Snellen chart. This is a large card or projection with progressively smaller horizontal lines of random block letters. The test determines how well a patient can discern detail at a given distance. Patients taking this test will cover one eye and then read aloud the letters of each row, starting from the top. The smallest row that can be accurately read indicates the patient’s visual acuity in that eye.
- Refraction: This test is used to find the best corrected vision, if necessary for prescription eyewear or contacts. The doctor will try various lenses in front of each eye, as the patient focuses on a chart at a distance or up-close, to help determine the best power of correction.
- Color vision: The doctor shows the patient a series of images with symbols embedded in color dots or patterns. Based upon the patient’s ability to identify the symbols, certain types of colorblindness can be diagnosed or ruled out.
- Ophthalmoscopy: This test is often done with an ophthalmoscope, a handheld instrument with light and magnifying lenses. Alternatively, the doctor may use other means, such as a slit lamp, which affords a more three-dimensional view. Ophthalmoscopy aims to inspect the retina and surrounding internal eye. This test can help diagnose problems with the retina or detachment of the retina, and monitor diseases like glaucoma and diabetes. An opacity in the eye can indicate a cataract. Sometimes the doctor will dilate the pupils with eye drops, to gain a wider view of the internal eye.
- Tonometry: This test measures intraocular pressure, which can be a sign of glaucoma if pressure is abnormally high. Internal eye pressure is measured either with a puff of air at the cornea or brief direct contact with the cornea, to measure how easily it is pushed inward.
LASIK Eligibility Evaluation
Do you suffer from nearsightedness, farsightedness, or astigmatism? Do you find glasses or contacts cumbersome or uncomfortable, and wish you could reduce their prescription or discard them?
If you answered “YES” to either of these questions, you may be a good candidate for LASIK or other vision corrective surgery. Before the decision can be made however, you must have an eligibility exam and consultation. The doctor will ask questions about your medical history and give a thorough eye exam designed to determine if the procedure is appropriate for your individual case. The doctor will also talk about the benefits, risks, available options, and preparation and recovery associated with the surgery to ensure that your goals and expectations are realistic.