The terms “low vision” and “blindness” are often used interchangeably, but they don’t mean the same thing. Understanding the distinction matters—both for patients navigating a diagnosis and for families trying to find the right support.
In this blog post, we’ll cover what low vision and blindness mean, how they differ, what conditions commonly cause each, and when it’s time to talk to your eye doctor.
What is low vision?
Low vision is a significant visual impairment that cannot be fully corrected with glasses, contact lenses, medication, or surgery. Patients with low vision still have usable sight, but their vision loss meaningfully interferes with everyday tasks like reading, driving, recognizing faces, or navigating unfamiliar spaces.
Low vision is generally defined as best-corrected visual acuity of 20/70 or worse in the better eye, or a significant reduction in visual field. To put that in perspective, someone with 20/70 vision has to be 20 feet away from something to see what a person with normal vision can see clearly from 70 feet.
Common characteristics of low vision include:
- Blurry or hazy central vision
- Blind spots or missing areas in the visual field
- Poor contrast sensitivity
- Difficulty with glare or bright light
- Trouble seeing in low-light conditions
What is blindness?
Blindness refers to a complete or near-complete loss of vision. Legal blindness, which is a specific clinical and legal threshold, is defined as best-corrected visual acuity of 20/200 or worse in the better eye, or a visual field of 20 degrees or less. A person who is legally blind may still have some residual vision.
In contrast, total blindness means no light perception whatsoever. This is far less common than legal blindness and represents the most severe end of the vision loss spectrum.
It is worth noting that many people who are considered legally blind still have some usable vision. The legal designation exists primarily to determine eligibility for certain services, benefits, and accommodations and not to describe the full experience of every person living with significant vision loss.
What causes low vision and blindness?
Many of the same underlying conditions can cause both low vision and blindness, depending on severity and how early they are caught and managed.
Age-related macular degeneration
Age-related macular degeneration (AMD) is one of the leading causes of low vision and blindness in adults over 50. It affects the central portion of the retina, making it difficult to read, drive, or see fine detail. While there is currently no cure, early detection and treatment can slow progression significantly.
Glaucoma
Glaucoma damages the optic nerve, typically beginning with peripheral vision loss. Because it develops gradually and often without symptoms, it is frequently diagnosed late, making regular eye exams especially important. Advanced, untreated glaucoma can lead to blindness.
Diabetic retinopathy
People with diabetes are at risk for diabetic retinopathy, a condition in which high blood sugar damages the blood vessels in the retina. It is a leading cause of vision loss in working-age adults and can progress to blindness if left unmanaged.
Cataracts
Cataracts cloud the lens of the eye and are a common cause of low vision, particularly in older adults. Unlike many other causes of vision loss, cataracts are treatable with surgery.
Retinitis pigmentosa
This inherited condition causes progressive degeneration of the retina, typically beginning with night blindness and loss of peripheral vision. It can eventually lead to significant vision loss or blindness.
Traumatic eye injuries
Accidents, foreign objects, and blunt force trauma can cause sudden and severe vision loss, ranging from low vision to total blindness, depending on the extent of damage.
Can low vision be treated?
Low vision cannot always be reversed, but it can often be managed. Low vision rehabilitation helps patients make the most of their remaining sight through a combination of strategies and tools, including:
- Magnification devices and specialized glasses
- High-contrast materials and lighting adjustments
- Screen readers and other assistive technology
- Orientation and mobility training
- Occupational therapy
The goal of low vision care is not to restore vision to normal, but to help patients maintain independence, safety, and quality of life. Many people with low vision continue to live full, active lives with the right support in place.
When should you see an eye doctor?
If you or a loved one is experiencing any of the following, it is time to schedule a comprehensive eye exam:
- Gradual or sudden vision changes
- Blurry, hazy, or distorted central vision
- Increasing difficulty reading, driving, or recognizing faces
- New blind spots or missing areas in your visual field
- Sensitivity to glare or difficulty adjusting to light changes
- A diagnosis of diabetes, high blood pressure, or another condition that affects eye health
Many conditions that lead to low vision or blindness are highly treatable, or at least manageable, when caught in time. The challenge is that many of them develop gradually with no obvious symptoms in the early stages, which is exactly why routine eye exams matter even when your vision seems fine.
Schedule an eye exam at Family Eyecare of Orange today and get ahead of vision changes.