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Is Bad Eyesight Genetic?
Updated on September 20, 2022
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Is Bad Eyesight Genetic?
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Eye problems affect millions of people in the United States. As of 2020, about 45.5 million Americans have them.

There are a lot of myths surrounding poor eyesight. But the one which says that genes cause bad eyesight isn’t a myth — it’s real.

Scientists have found a link between genes and vision problems.1 Your parents, grandparents, and even great-grandparents can pass on the traits.

A child whose parents have good eye health still has a 1 in 40 chance of developing nearsightedness.

Is Bad Eyesight Genetic? 2
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How Genetics Cause Bad Eyesight

Nearly every cell in the body contains deoxyribonucleic acid or DNA. Together, your DNA makes up your genes.

Genes are like instruction manuals for the rest of your body. They dictate how your genetic code should be arranged. 

This sequencing determines your traits. It can influence your physical appearance, health risks, and behavior. 

Unfortunately, it's not just the good traits that are passed along. Studies show that you can inherit “bad genes” that cause poor vision.2 

You can also inherit eye diseases through a mutated gene. Eye conditions like glaucoma may develop from hereditary illnesses such as diabetes.

Do Bad Genes Always Cause Poor Eyesight?

No. Bad genes don’t always cause poor eyesight. The genes linked to ocular problems aren't always passed on or inherited. 

But if bad eyesight runs in the family, there is a higher chance that you or your children may have vision impairments.

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Most Common Genetic Eye Diseases

DNA tests that can detect your risk for certain eye disorders are still in the early stages of development. But scientists have uncovered genetic markers linked to bad vision.

Below are some common vision problems which are passed on genetically.

1. Myopia or Nearsightedness

Myopia is a refractive error that causes you to become nearsighted. People with myopia can see nearby objects clearly, but not when the objects are far. 

You have a higher risk of developing myopia if your parents are nearsighted. But if only one of them has it, your chances decrease to 1 in 5.

Like other refractive errors, there's a quick fix for nearsightedness. You can wear glasses or prescription contact lenses to improve your eyesight.

2. Cataracts

A cataract is an eye condition where a naturally clear lens becomes cloudy. Symptoms include double or blurry vision, light sensitivity, and difficulty seeing at night. 

People with advanced cataracts have a visible white film on the affected eye. They may also see bright hues as faded colors or yellow.

Evidence shows that certain genes increase your risk for age-related cataracts.3

3. Age-Related Macular Degeneration (AMD)

Age-related macular degeneration (AMD) is the leading cause of vision impairment in people aged 50 and above.4 It is a common degenerative disease in the elderly.

The condition damages your macula, which helps with straight vision and sharp visual acuity. While AMD doesn't cause permanent blindness, it can impair your near vision and lead to central vision loss.

As a result, people with this eye condition usually struggle with simple tasks. You may have difficulty reading, driving, seeing faces, cooking, and doing other things up close.

According to the American Optometric Association (AOA), having family members with AMD can increase your risk. You're also more likely to develop it when you’re over 40.

4. Glaucoma

Glaucoma is a progressive condition that causes increased eye pressure. Left untreated, it can damage the optic nerve and cause permanent vision loss.

The most common type is primary open-angle glaucoma, which can be inherited. You are at a higher risk if anyone from your immediate family has it.5

You can lower your chances of developing glaucoma by:

  • Watching your weight
  • Limiting your caffeine intake to keep a low eye pressure
  • Exercising daily

5. Diabetic Retinopathy (DR)

Diabetic retinopathy is an eye disorder that occurs as a complication of diabetes. It damages the retina's blood vessels and deprives it of oxygenated blood.

Its symptoms include blurred vision and seeing empty spaces. Without treatment, it can worsen glaucoma and cause retina damage and permanent blindness.

6. Retinitis Pigmentosa (RP)

Retinitis pigmentosa is a degenerative disease that causes the cells in your retina to break down. It is characterized by peripheral vision loss and difficulty seeing at night. 

Research shows that a genetic mutation in the X chromosome causes this condition. You have a 25% chance of developing RP if both parents have the gene.

The condition may cause more eye conditions, such as glaucoma and blindness.

7. Strabismus

Strabismus or "crossed eyes" is a disorder that affects the eye muscles. It causes your eyes to cross inwardly (esotropia) or outwardly (exotropia). 

People with strabismus have eyes that appear misaligned or look in different directions.

It can occur at birth though it's also common in children. If strabismus isn't corrected early, it can cause permanent vision loss in one eye.

Genetic Testing for Eye Problems

You can assess your risk for most eye diseases through DNA testing and your family history. Eye doctors can help diagnose and treat these conditions. 

DNA tests can check for genetic mutations that may cause poor vision. So far, scientists have identified at least 500 different genes related to eye disorders. 

A geneticist will use this information to assess your risks. In turn, you can inform your eye doctor about them.

Benefits of Genetic Testing for Eye Health

Genetic testing offers advantages for people with eye problems or a family history of poor eyesight. These include:

  • Identifying risks for hereditary eye conditions
  • Getting tested for gene mutations
  • Taking steps to prevent eye disease
  • Starting treatment early
  • Improved prognosis and eye health

A DNA test also helps doctors provide specialized care based on your needs. 

For example, open-angle glaucoma doesn’t show symptoms until there is significant vision loss. With genetic testing, the doctor can tell if you’re at risk. 

They can assess you for glaucoma if testing confirms that you carry its gene mutation. Doctors can also educate you on how you can lower your risk for glaucoma.

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23andMe - The best for Health and Diseases

23andMe offers the only health test that’s authorized by the FDA. For this reason alone, 23andMe should be your first choice when searching for a DNA test kit to check for health conditions.

Other Factors That Cause Poor Eyesight

Genetic mutations aren’t the only reason behind bad eyesight. Environmental factors can also lead to cataracts, glaucoma, dry eye, and other eye problems.

Here are some factors that contribute to poor eyesight:

  • Pollutants
  • Toxic gases
  • Chemicals
  • Bacteria
  • Drugs
  • UV radiation
  • Cosmetic products

Find Out If You Have an Eye Problem

Set up an appointment with an eye doctor who can review your medical background and family history. They will have you undergo standard tests to assess your vision. 

Some might request a DNA test to check your risk for common eye problems. You can take at-home DNA testing kits that find related genetic markers.

Your doctor might schedule a regular eye exam if you’re at risk for degenerative eye disorders. They can monitor your eye health and provide personalized care.

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Resources

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  1. Genes and genetics in eye diseases: a genomic medicine approach for investigating hereditary and inflammatory ocular disorders.” International Journal of Ophthalmology.
  2. Genetic Testing for Inherited Eye Disease: Why, How, and Who.” American Academy of Ophthalmology. 
  3. Genetics of human cataract.” National Center for Biotechnology Information.
  4. Macular Degeneration.” American Optometric Association.
  5. Are You at Risk For Glaucoma?” Glaucoma Research Foundation.
Cristine Santander
Cristine Santander
Content Contributor
Cristine Santander is a content writer for KnowYourDNA. She studied B.S. Psychology and enjoys writing about health and wellness.
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