Blindness has many causes, such as eye injuries, eye surgery complications, or health conditions, such as diabetes or stroke. Some causes of blindness are also genetic.
According to the
In this article, we examine how often blindness is genetic, eye conditions with a genetic component, and rarer hereditary forms of blindness.
Many things can cause vision loss or blindness. Some of these causes are genetic. For example, a person may inherit a genetic condition that causes blindness from birth. This is known as congenital blindness.
Alternatively, genetics can make a person more likely to develop conditions that cause blindness during their lifetime. This may be due to a condition that directly affects the eyes or another condition that can cause eye-related complications.
Recent data on how often congenital blindness occurs is lacking.
According to the CDC, almost
Genetic factors can play a role in the following conditions:
Age-related macular degeneration (AMD)
AMD is an eye disease that occurs when aging damages the macula. The macula is part of the eye that controls sharp, straight-ahead vision.
AMD is the
Genetic factors can influence when AMD may start and how it progresses. Researchers have identified numerous genes linked to a risk of AMD.
People with a family history of the disease are more likely to develop it than those without. Around 15–20% of people with AMD have one or more first degree relatives with the condition, such as a parent or sibling.
AMD symptoms include:
- blurriness in central vision
- trouble seeing in low lighting
- straight lines appearing crooked or wavy
- colors losing their brightness
- blank spots
Glaucoma is a group of progressive eye diseases that damage the optic nerve that connects the eye to the brain, resulting in vision loss and blindness.
Glaucoma affects about
Many people with glaucoma have no family history of the condition. However, some research indicates that around
Glaucoma symptoms depend on the type and severity but may include the following:
- patchy blind spots to the side
- trouble seeing in front
- severe eye pain
- severe headache
- blurry vision
- halos around lights
- a dull, cloudy eye
Treatment cannot reverse the damage glaucoma causes, but it can help prevent or reduce vision loss.
A cataract is when the eye’s lens, which is usually clear, develops cloudy patches. The patches can get larger, causing blurry, misty vision. It can cause very poor vision if not treated for a long time.
Cataracts from birth, known as congenital cataracts, sometimes happen when a gene passes from parent to child.
The National Health Service (NHS) in the United Kingdom estimates that 1 in 5 people with congenital cataracts have a family history of the condition. Genetics may also play a role in some age-related cataracts.
Symptoms of cataracts may include:
- cloudy or blurry vision
- faded color perception
- difficulty seeing at night
- halos around lights
- double vision
Surgery is the most effective treatment for cataracts. Cataract surgery replaces the cloudy lens with an artificial one.
Amblyopia is a type of vision impairment that happens when the brain and eye do not work together correctly, causing the brain not to recognize sight from the eye.
The condition typically affects one eye, with the brain relying more on the stronger eye. This worsens the vision in the weaker eye, causing what some people call “lazy eye.” Without treatment, amblyopia can cause permanent vision loss.
Amblyopia starts in childhood, affecting up to
- poor depth perception
- shutting one eye
- tilting the head
Many parents and caregivers are unaware their child has amblyopia until they have an eye exam. Doctors recommend children have a vision screening between
A group of rare genetic conditions known as inherited retinal diseases (IRDs) can also lead to vision loss and blindness.
Research has identified more than 260 genes that cause IRDs. These conditions affect more than
Examples of IRDs include:
- Retinitis pigmentosa: Retinitis pigmentosa is a group of inherited eye disorders that deteriorate the retina’s light-sensing cells, causing vision loss. It affects
1 in 4,000people in the United States.
- Choroideremia: This is a genetic disorder that causes progressive vision loss resulting from an ongoing loss of cells in the retina and nearby blood vessels. It typically affects males. People with this condition first experience impaired night vision, followed by tunnel vision and a reduced ability to see details. Choroideremia affects fewer than 50,000 people in the United States.
- Stargardt disease: This genetic eye disease occurs when fatty material accumulates on the macula. Stargardt disease causes progressive vision loss. Fewer than 200,000 people in the United States have it.
- Cone-rod dystrophy: This group of inherited eye disorders affects the retina’s light-sensitive cells called the cones and rods. People experience gradual vision loss as the cones and rods deteriorate. It affects around 1 in 30,000–40,000 people.
- Lever congenital amaurosis: People with this genetic eye disorder have a severe visual impairment, typically from birth. It occurs in roughly 2–3 in 100,000 newborns.
- Achromatopsia: This inherited vision disorder causes people to have a partial or complete absence of color vision with blind spots, blurriness, and low vision. Achromatopsia affects around 1 in 30,000 people worldwide.
- X-linked retinoschisis: X-linked retinoschisis affects the cells in the macula, leading to low sharpness of vision in both eyes. Complications can cause blindness. This genetic condition affects males. Doctors typically diagnose it in childhood.
No cure exists for most IRDs, but doctors use strategies to slow vision loss and preserve sight for as long as possible.
Blindness is not always genetic, but it can be.
Some causes of blindness are entirely due to genetics. For other causes, family history is just one of several risk factors. Depending on the condition, blindness could be present at birth or develop later in life.
Several common eye conditions that can lead to blindness have a genetic component, such as AMD and amblyopia. There are also rarer genetic conditions that can cause blindness, known as IRDs.