What is myopia?
Myopia is the medical term for nearsightedness. People who have myopia have difficulty seeing distant objects, but can clearly see objects that are near. For example, a person who has myopia may not be able to read highway signs until they are just a few meters away, or may not be able to make out what’s on the board in school, but can read a book held up close without difficulty.
Some of the telltale signs of myopia include blurred distant vision, eyestrain, headaches and squinting when looking at distant objects.
Myopia occurs if the eyeball is too long or the cornea (the clear front cover of the eye) is too curved, causing a refractive error, meaning the light rays bend incorrectly into the eye to transmit images to the brain. Instead of focusing directly on the retina, they focus in front of the retina, the light-sensitive part of the eye, causing blurred vision.
Myopia may develop in children as young as 5 years old.
How prevalent is myopia?
Myopia may develop in children as young as 5 years old. Because the eye continues to grow during childhood, it typically progresses and then stabilizes at about age 20, but sometimes it continues to progress with age. Myopia may also develop in adults usually due to visual stress or a complication from other health problems such as diabetes.
Myopia affects more than a billion people around the world. It has become more prevalent in recent years, now affecting a whopping 42% of people ages 12- 54 in the United States alone.
With more and more people developing myopia these days, it is important to discover ways to control the progression of myopia in children. This includes proactive means of treatment, such as yearly eye exams for children starting at five years old.
A yearly eye exam starting at 5 years old is important in preventing myopia.
Although an outright cure for nearsightedness has not been discovered, your eye doctor can now offer a number of treatments that may be able to slow the progression of myopia. There are four main treatments currently being used to control myopia:
- Atropine eye drops –Research has suggested that nearsightedness in children may be linked to focusing fatigue. And because Atropine causes the muscles in your eye to become relaxed, doctors have looked into using atropine to disable the eye’s focusing mechanism to control myopia. Results of studies of atropine eye drops to control myopia progression have been impressive — at least for the first year of treatment.
- Multifocal contact lenses – Multifocal contact lenses have been shown to slow the progression of myopia. The reason they apparently work is because they create a ring of increased power surrounding central vision that the eye interprets as a “stop signal” for further growth. When eyes grow longer, they become more myopic. The signals for this growth are in the peripheral retina.
Multifocal contact lenses correct or reduce accommodative lag, which is considered a stimulus for eye elongation. They reduce the peripheral retinal defocus, which is considered to increase the risk of eye elongation by shifting the image closer to the retina. The lenses impose myopic defocus across areas of the retina, which is considered to inhibit eye growth.
- Orthokeratology (“ortho-k”) – In the simplest terms, ortho-k entails flattening or reshaping the anterior corneal surface in an effort to adjust the eye’s refractive power. It requires the use of specially designed gas permeable contact lenses that are worn during sleep at night to temporarily correct nearsightedness and other vision problems so glasses and contact lenses aren’t needed during waking hours.
Much like orthodontic braces for your teeth. The lens reshapes the corneal surface to a specific contour, which easily can be adjusted to enhance the desired effect in safe, overnight lens wear. The effect is not permanent, meaning it is reversible, but the good thing about ortho-k is it allows you to function without contacts or eyewear throughout the daytime hours.
Eyeglasses are the first choice of many for myopia correction.
- Multifocal eyeglasses – These are the most common method to correct myopia. Multifocal eyeglasses are prescription lenses for spectacle frames worn on the face to change the eye’s focus. If the eye is nearsighted for example, a lens is normally designed to give clear distance vision. Sometimes this is called a monofocal lens. A bifocal lens has two powers which can be located at different locations on the lens. In glasses, the bifocal power is usually located at the bottom of the lens. Multi-focal eyeglasses have multiple reading powers below the central vision to allow vision at different distances without the eye’s focusing ability being necessary.
Multifocal glasses are worn during the day for clear vision for both near and distant objects. They are worn every day although occasionally a day without the lenses will not adversely affect the treatment. Objects in the distance are viewed in the upper portions of the lenses and objects nearby are viewed through the lower portions. The lenses are worn as long as myopia progression is considered a risk.
Prevention is obviously the most effective strategy to reduce the burden of myopia.
The rapid growth of myopia is as a danger, and as scientists continue to research new treatments, it is up to optometrists to continue to help children and adults suffering from the symptoms to treat and control their myopia.
Testing for myopia may use several procedures to measure how the eyes focus light and to determine the power of any optical lenses needed to correct the reduced vision. Nearsighted people should receive regular eye exams to ensure their prescription remains accurate, especially in the teenage years when myopia worsens and prescriptions change frequently.
If you have myopia, you have a variety of options to correct your vision problem. In consultation with your optometrist, you can select the treatment that best meets your visual and lifestyle needs.
About the Author
The Institute for Control of Eye Myopia in Children’s mission is to improving the quality of life for children with worsening vision. We are a resource for parents that offers a simple explanation of the physiologic mechanisms believed to cause progressive myopia and what scientific evidence has shown might prove or disprove the effectiveness of the various methods offered by eye care professionals. We also provide referrals to doctors across the country with experience applying the latest science to help slow down or stop your child’s worsening vision.