Causes of Low Vision

Woman struggling with vision

Eye Conditions That Cause Low Vision

Low vision causes permanent changes to your eyesight that can make life a little more challenging. You may have low vision if you can’t see well, even when wearing prescription eyeglasses. If the best you can see with your glasses is 20/70 to 20/160, you have moderate low vision, according to a low vision classification used by the World Health Organization. Other categories of low vision include:

  • 20/200 or Higher: Severe low vision
  • 20/500 to 20/1000: Profound low vision
  • Less than 20/1000: Near-total low vision

These eye diseases and conditions can affect your eyesight, causing low vision.

Diabetic Retinopathy

Keeping your glucose (blood sugar) level under control is essential if you have diabetes. When your blood sugar is consistently too high, you may be more likely to develop heart disease, nerve damage, high blood pressure, kidney damage, or vision loss.

Diabetic retinopathy occurs when abnormal blood vessels grow in your retina. The retina lines the back of your eye and sends electrical impulses to the brain, which then converts them to images. Abnormal blood vessels leak blood or fluid, interfering with vision. Damage to the retina can also occur in some cases.


Increased pressure inside the eye can damage your optic nerve, the pathway between the eye and the brain, if you have glaucoma. If the optic nerve is damaged, some or all of the electrical impulses sent by the retina won’t reach the brain depending on the extent of the damage. As a result, you may develop blind spots or even lose your vision completely.

Pressure changes can happen gradually or suddenly. Gradual changes usually don’t cause any symptoms until your vision is permanently damaged.

Fortunately, visiting your optometrist for yearly eye exams can help you avoid vision loss caused by glaucoma. During your exam, your eye doctor will test the pressure inside your eyes and dilate your eyes to view your optic nerve.

Torn or Detached Retina

If your retina tears or separates from the back of the eye, you may notice blind spots in your vision or feel as if a dark curtain has fallen over your eye. Unfortunately, if you don’t receive prompt treatment for a tear or detachment, you may experience some degree of permanent vision loss.

Eye injuries and aging are the most common causes of retinal detachments, according to the National Eye Institute. Other causes include eye injuries, certain eye disorders, or previous surgery on the eye.

Macular Degeneration

Macular degeneration, a common age-related eye disorder, affects the central part of your vision. Cells in the macula, the center part of your retina, begin to degenerate, creating blurry or blind spots. These spots make it hard to read, drive, or recognize faces.

If you’re diagnosed with macular degeneration, your eye doctor will tell you whether you have the wet or dry form. The dry type occurs when the macula thins and yellow deposits called drusen form under the retina. The wet form happens when abnormal blood vessels grow in the macula and leak. Injected medication or laser therapy may be helpful if you have the wet form of the disorder. Unfortunately, there is no treatment for the dry form yet.


A cataract happens when the normally clear lens inside your eye becomes cloudy. The lens focuses light on your retina and plays an important part in the visual process. When the lens becomes cloudy, you may notice that colors are duller and everything looks a little blurry. Glare and halos around lights may also be a problem.

Most people notice an improvement in their vision after cataract surgery. The surgery involves removing the clouded lens and replacing it with an artificial lens implant. If you have cataracts and also have other eye diseases, like macular degeneration or diabetic retinopathy, you may still have some trouble seeing after your surgery.

Retinitis Pigmentosa

Cells in the outer part of the retina begin to degenerate in retinitis pigmentosa (RP). As time goes on, your side vision slowly shrinks, leaving you with only a small amount of central vision. RP also makes it hard to see at night or in low light. The condition is inherited and often causes legal blindness by age 40, according to the Foundation Fighting Blindness.

Are you struggling to live with low vision? Low vision aids can help you make the most of your remaining vision. Your optometrist can help you find the most effective visual aids for your condition. Contact our office to schedule a visit with the eye doctor.


National Eye Institute: Retinal Detachment

Foundation Fighting Blindness: What Is Retinitis Pigmentosa?

American Optometric Association: Low Vision and Vision Rehabilitation

American Academy of Ophthalmology: Causes of Low Vision, 6/14/21

National Eye Institute: Low Vision



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