Nearsightedness
What is nearsightedness? What is refraction? Nearsightedness, also known as myopia, is a Refraction is the bending of light as it passes common type of refractive error where close objects through one object to another. appear clearly, but distant objects appear blurry. Vision occurs when light rays are bent (refracted) RETINA VITREOUS GEL as they pass through the cornea and the lens. The light is then focused on the retina. The retina IRIS converts the light rays into messages that are sent through the optic nerve to the brain. The brain interprets these messages into the images we see. CORNEA Image focused on the retina What are refractive errors? PUPIL MACULA In refractive errors, the shape of the eye prevents light from focusing on the retina. The length of LENS OPTIC NERVE the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens can Normal cause refractive errors.
How does nearsightedness develop? VITREOUS GEL RETINA Nearsightedness develops in eyes that focus IRIS images in front of the retina instead of on the retina, which results in blurred vision. This occurs when the eyeball becomes too long and prevents CORNEA Image focused in incoming light from focusing directly on the the front of the retina. It may also be caused by an abnormal retina PUPIL shape of the cornea or lens. MACULA
LENS Who is at risk for nearsightedness? OPTIC NERVE Nearsightedness can Myopia affect both children and (nearsightedness) adults. The condition affects about 25 percent of The cornea and lens bend (refract) incoming light rays so Americans. Nearsightedness they focus precisely on the retina at the back of the eye. is often diagnosed in children between 8 and 12 years of age and may Contact Lenses work by worsen during the teen years. Little change may becoming the first refractive occur between ages 20 to 40, but sometimes surface for light rays nearsightedness may worsen with age. People entering the eye, causing whose parents are nearsighted may be more likely a more precise refraction to get the condition. or focus. In many cases, contact lenses may provide clearer vision, wider What are the signs and symptoms of field of vision, and greater comfort. They are a safe nearsightedness? and effective option if fitted and used properly. However, contact lenses may not be the best Some of the signs and symptoms of option for everyone. nearsightedness include the following:
• Headaches If you have certain eye conditions, you may not • Eyestrain be able to wear contact lenses. Discuss this matter • Squinting with your eye care professional. • Difficulty seeing distant objects, such as highway signs Refractive Surgery aims to permanently change the How is nearsightedness diagnosed? shape of the cornea, which An eye care professional can will improve refractive diagnose nearsightedness vision. Surgery can decrease and other refractive errors or eliminate dependency during a comprehensive on wearing eyeglasses and contact lenses. There dilated eye examination. are many types of refractive surgeries and surgical People with this condition options should be discussed with an eye care often visit their eye care professional with professional. complaints of visual discomfort or blurred vision. For more information about refractive errors and eye How is nearsightedness corrected? health, visit http://www.nei.nih.gov/healthyeyes. Nearsightedness can be corrected with eyeglasses, contact lenses, or refractive surgery.
Eyeglasses are the simplest and safest way to correct nearsightedness. Your eye care professional can prescribe lenses that will correct the problem and help you to see your best.