Nearly 30 percent of all people in the United States are nearsighted, and that percentage is on the rise. A new study by scientists at Duke University Medical Center has discovered a gene that is associated with nearsightedness. The study shows that the gene is a contributing factor for myopia for Caucasian people from specific regions including people who are Dutch, British, or Australian. Other studies are working to determine if the same gene is involved in nearsightedness for people from other regions.
Nearsightedness, which is also called myopia, is a visual condition that happens when the eyes are able to focus clearly on objects that are close up, but objects farther away appear blurry or out-of-focus. Nearsightedness occurs when the eyeball is too long (football-shaped instead of round) or when the cornea, which is the clear front cover of the eye, is curved too much. In clear vision, light entering the eye is focused precisely on the back wall of the eyeball. In myopia, the shape of the eyeball or the curve of the cornea causes the light to fall short of the back of the eye which causes the image to appear out of focus.
The discovery of a gene linked to nearsightedness gives researchers a new approach to treating the condition. Genetic therapy is often slow to develop due to difficulties getting treatment to genes that are spread over a large part of the body. Dr. Terri Young, lead author of the study and professor of ophthalmology, pediatrics, and medicine, and a researcher in the Center for Human Genetics at Duke said, “The eye is already an organ of choice for gene therapy, for example, because the eye’s small volume and self-contained area allow the therapy to remain inside the eye in a concentrated volume.” Another advantage for researchers in treating eye conditions is the easy access to the inside of the eye to study the results of attempted treatments.
The amount of nearsightedness in a population can have significant impacts on a region or country. Researchers site the example of people in Singapore, where up to 80 percent have myopia. Populations with a high percentage of people with myopia can have difficulties filling certain roles in society requiring clear vision, such as fighter pilots. Some cases of myopia are mild while a small percent are serious cases that include retinal detachment, macular bleeding, and glaucoma which can lead to blindness.
Researchers recommend a simple strategy to help reduce problems with nearsightedness – look to the distant horizon. Modern society puts an emphasis on close work including working on computers, watching television, and spending large amounts of time inside buildings or surrounded by buildings that limit access to long-distance vision. These situations cause tension in the eyes as they work to focus close up, which can become a lasting case of myopia. Children and adults can benefit from relaxing the eyes by looking at objects that are far away.
A gene for farsightedness was identified by researchers in Australia early in 2010.