It’s a loss of sight that can’t be corrected with prescription eyeglasses, contact lenses, or surgery. Low vision doesn’t include complete blindness, because you will have some sight left. It can be treated or offset, however, with vision aids like magnifying glasses.
The condition includes different degrees of sight loss. You might have a blind spot or an almost complete loss of sight. The Academy of Ophthalmology divides low vision into two categories based on the vision in your best eye:
Partially sighted: Your vision is between 20/40 and 20/200 with conventional prescription lenses.
Legally blind: Your vision is no better than 20/200 with conventional correction, or you have a restricted field of vision less than 20 degrees wide.
What Are the Types of Low Vision?
The most common ones include:
- Loss of central vision. You have a blind spot in the center of your field of vision.
- Loss of peripheral (side) vision. You can’t see anything to either side or above or below eye level. But your central vision remains intact.
- Night blindness. You don’t see well in poorly lit places like theaters or outside at night.
- Blurred vision. Objects both near and far are out of focus.
- Hazy vision. Your entire field of vision seems to be covered with a film or glare.
What Causes Low Vision?
It’s the result of a variety of conditions and injuries. Age is also a factor. Eye problems like macular degeneration, glaucoma, cataracts, and optic neuropathy are more common among people over 45 and even more so if you’re over 65.
Besides age-related retinal conditions, other possible causes include:
How Is Low Vision Diagnosed?
You’ll need an eye exam. Make an appointment with your eye doctor if vision troubles prevent you from daily activities like reading, travel, cooking, work, watching television, or school.
Your eye doctor will use lighting, magnifiers, and special charts to test your visual acuity, depth perception, and visual fields.
Can It Be Treated?
Some sight disorders, like diabetic retinopathy, can be treated to restore or maintain vision. When this isn’t an option, low vision is permanent. However, many people with low vision find visual aids helpful. Popular products include:
- Telescopic glasses
- Lenses that filter light
- Magnifying glasses
- Handheld and freestanding magnifiers
- Closed-circuit television/video magnification
- Reading prisms
Non-optical aids designed for people with low vision are also very helpful. Some popular devices include:
- Text-reading software
- Text to voice devices
- Smart phone apps
- Check-writing guides
- High-contrast clocks and watches
- Talking watches and clocks
- Large-print publications
- Clocks, phones, and watches with large numbers
- Books on DVD/CD/audiocassette
Visual aids can improve both your sight and quality of life. Ask your doctor where to get them.
Can It Be Prevented?
It may be prevented for patients with diabetes. It can be reversed if it’s caused by cataracts.