Version May 2024
| Visual acuity is typically measured monocularly rather than binocularly with the aid of a chart and an occluder to cover the eye not being tested. The examiner may also occlude an eye by sliding a tissue behind the patient's eyeglasses or instructing the patient to use his or her hand. The latter method is typically avoided in professional settings as it may inadvertently allow the patient to peek through his or her fingers, or press the eye and alter the measurement when that eye is evaluated. |
| 1. Place the chart at 20 feet (or 6 meters) and illuminate the chart adequately. |
| 2. If the patient uses glasses, then the test is performed using them. |
| 3. Place the occluder in front of the eye that is not being evaluated. The first evaluated eye is the one that is believed to see less or the one the patient says is seeing less. |
| 4. Start with the big letters and proceed to the smaller ones. The patient has to identify every letter on the line being presented and communicate it to the physician. |
| 5. If the measurement is reduced, then visual acuity can be tested using a pinhole occluder to confirm visual impairment. If performed, both measures should be registered with and without using the pinhole occluder. |
| 6. Change the occluder to the other eye and proceed again from the 4th step. |
| 7. After both eyes have been evaluated in distant visual acuity, proceed to evaluate near visual acuity by placing a modified Snellen chart for near vision (such as the Rosenbaum chart) at 15.7 inches (or 40 centimeters). Then repeat the test from the 2nd step. |
| In some cases, binocular visual acuity will be measured, because usually binocular visual acuity is slightly better than monocular visual acuity. |
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
