By Dr. Jessica Sapp, Associate Professor, School of Health Sciences, and Sangeetha Ravi, Master of Public Health Graduate Student, American Public University
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There are different reasons people are affected by blindness or visual impairment, including diabetes, stroke, or eye infections. The World Health Organization says “approximately 80 percent of visual impairment globally is considered avoidable.” Avoidable blindness is defined as blindness that could be either treated or prevented by known, cost-effective means.
Common Causes of Blindness or Other Vision Problems
According to the Centers for Disease Control and Prevention (CDC), the leading causes of blindness and low vision in the United States are refractive errors, age-related macular degeneration, cataract, diabetic retinopathy, and glaucoma.
Refractive errors: Refractive errors such as myopia, hyperopia, presbyopia and astigmatism occur when the shape of the eye prevents light from focusing directly on the retina. This problem causes visual discomfort and blurred vision.
Age-related macular degeneration: This condition is an eye disorder associated with aging. It is the leading cause of vision loss for people age 50 and older. It occurs when the small central portion of the retina, known as the macula, is damaged. As a result, a person cannot see fine details.
Cataract: This medical condition, due to opaque areas in the clear lens of the eye, is a common cause of blindness in people over age 55. The clouded vision caused by cataracts makes it more difficult to read and drive a car, especially at night. Cataracts can also lead to vision loss.
Diabetic retinopathy: Diabetic retinopathy is the most common cause of vision loss among people with diabetes. It affects blood vessels of the retina of an eye, leading to vision impairment and blindness.
Glaucoma: Glaucoma is a group of diseases that damages the eye’s optic nerve, which results in vision loss and blindness. It usually happens when fluid builds up in the eye. The extra fluid increases the pressure in the eyes and damages the optic nerve.
Amblyopia: This condition is also known as “lazy eye.” It occurs when vision in one or both eyes does not develop properly during childhood. If it is not treated early enough, an amblyopic eye may never develop good vision and may even cause someone to become functionally blind.
Getting Regular Eye Exams to Check Your Vision
Regular eye care can have a life-changing impact on preserving the vision of millions of people. Eye diseases are common and remain unnoticed for a long time, since many of them don’t have signs and symptoms in the early stages. To prevent blindness, regular eye examinations are essential to catch eye diseases in the early phases when treatment is most effective.
During a comprehensive eye exam, tests for visual acuity, depth perception, eye alignment, and eye movement are performed:
- Visual acuity: This test is a quantitative measure of the ability to identify black symbols on a white background at a standard distance. It is a clinical measurement of visual function.
- Depth perception: The brain processes different pictures from each eye and combines them to form a single, three-dimensional image. This test helps you accurately perceive how far away people or objects are from you. This function is measured in depth perception.
- Eye alignment: This test determines whether a person can align both eyes simultaneously. Eye alignment problems, such as diplopia or double vision, are usually caused by the inability of the eyes to work together.
- Eye movement: This test measures how the eyes move in response to images, light, moving objects and head motion. It detects eye muscle disorders as well as neurological conditions affecting the eyes.
In addition, the inner part of the eye along with the optic nerves are evaluated for abnormalities and eye diseases.
Take Your Kids for Regular Eye Exams, Too
We often think of adults over 40 years old getting eye exams, but children need them too. Experts recommend that a child’s first comprehensive eye exam should occur at six months of age.
Dr. Gary Heiting explains how additional eye exams should be done at 3 years old and before entering first grade. School-aged children should get eye exams every two years if there are no vision problems or obtain the tests annually if they need corrective lenses.
Other Reasons to See Your Eye Doctor
If you experience any of the following eye problems or symptoms, you should visit your eye doctor immediately. Don’t wait for your next eye appointment.
- Decreased vision
- Draining or redness of the eye
- Eye pain
- Double vision
- Floaters (tiny specks that appear to float before your eyes)
- Circles (halos) around lights
- Flashes of light
Tips to Maintain Good Vision Health
You can prevent vision problems, even as you get older. Follow these tips to keep your eyes healthy:
1. Wear sunglasses: Wearing 100 percent ultraviolet (UV) sunglasses is a great defense against UV rays. UV rays can cause short- and long-term eye damage such as cataracts, macular degeneration, pterygia and photokeratitis. Eyes need protection even on cloudy days, because the sun's damaging UV rays can penetrate cloud cover.
2. Wear protective eyewear: Eye injuries in the workplace as well as during household chores are very common. Safety glasses provide eye protection for general working conditions where there may be dust, chips or flying particles. You should also wear eye protection during household projects, such as yard work or other jobs involving the use of toxic chemicals.
3. Get a regular eye exam: An eye exam helps detect eye problems at their earliest stage when they're most treatable.
4. Eat eye-healthy foods: Eating a balanced diet high in fruits and vegetables, but low in saturated fats and sugar, enhances vision health. Adequate amounts of minerals such as zinc and selenium are needed to help protect the retina, the light-sensitive part of the back of the eye.
5. Be physically active: Regular exercise reduces the risks for several common eye ailments, such as cataracts, age-related macular degeneration and glaucoma. Cardiovascular exercises such as aerobics can lower pressure in your eyes and are beneficial to people with glaucoma.
6. Rest your eyes: Resting your eyes alleviates the hard work they perform by continually maintaining focus on nearby objects or glowing screens. Purposely blinking more frequently keeps the eyeballs moist and the eye muscles relaxed.
Try using the 20–20–20 rule throughout the day. Every 20 minutes, look away from your screen and focus your eyes about 20 feet in front of you for 20 seconds.
Getting a regular eye exam is important like an annual physical or teeth cleaning. You should make eye exams part of your regular preventive health routine. Schedule your eye examination today so you can see clearly tomorrow.
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About the Authors
Dr. Jessica Sapp is an associate professor in the School of Health Sciences at APUS. She has over 13 years of experience in public health, working in various environments including government, hospitals, health insurance, community, international, corporate and academia. Jessica earned her D.P.H. in health policy and management at Georgia Southern University and a M.P.H. in health promotion, education and behavior at the University of South Carolina. She also has a B.S. in health science education from the University of Florida.
Sangeetha Ravi is a Master of Public Health graduate student at APU. She is a primary care physician who worked in a community hospital in India for six years. Sangeetha earned her M.B.B.S (Bachelor of Medicine and Bachelor of Surgery) at Coimbatore Medical College in India. She has over four years of experience in the development and implementation of the dengue epidemic control program, elderly fall prevention program, and pulse polio immunization program.