264 Medical Terminology: Mastering the Basics During an eye exam, the patient covers one eye at a time and reads aloud the smallest line of letters that he or she can see on the Snellen chart. Visual acuity is expressed as a fraction. The top number refers to the distance from which the patient reads the chart, typically 20 feet. The bottom number indicates the distance from which a per- son with normal vision can read the line. Vision of 20/20 is considered normal. A reading of 20/30 indicates that the line read by the patient read at a distance of 20 feet away can be read by a person with normal vision at a distance of 30 feet away. Abnormal results of a visual acuity test may indicate a need for glasses or contact lenses due to an eye condition that needs further evaluation by an ophthalmologist, such as astig- matism, myopia, or hyperopia. Besides attempting to read the smallest line of type on the Snellen chart, the patient may be asked to read letters or numbers from a card held 14 inches from the face in a test of near vision. For very young children or patients who cannot read, visual acuity is tested with pic- tures instead of letters. Blepharoplasty Blepharoplasty (BLĔF-ă-rō-PLĂS-tē) is the surgical repair of drooping eyelids (Figure 6.10). It can be both a functional (necessary) and a cosmetic surgery. During the procedure, excess skin and fat are removed or repositioned, and sur- rounding muscles and tendons may be reinforced. With age, the eyelids stretch and muscular support weakens, resulting in excess fat above and below the eyelids. This causes sagging eyebrows, drooping upper lids, and puffy “bags” under the eyes. Severely sagging skin around the eyes can impair peripheral (side) vision. Blepharoplasty can reduce or eliminate impaired vision and improve appearance. Fluorescein Angiography Fluorescein (flor-ĔS-ē-ĭn) angiography (ĂN-jē-ŎG-ră-fē) is a photographic method of imaging the retina. A fluores- cein dye (an orange fluorescent dye) is injected into a vein in the patient’s arm. As the dye circulates throughout the body, multiple photographs are taken of the blood vessels in the eye. Fluorescein angiography is used to diagnose and document eye disease and to monitor response to therapy. It aids the physician in diag- nosing retinal and vascular disease, diabetes, macular degeneration, intra- ocular tumors, and other conditions. Radu Bercan/Shutterstock.com Figure 6.9 The Snellen chart is used to test visual acuity.