Low vision is a medical condition in which the loss of sight cannot be corrected with contact lenses, eyeglasses, or any surgery. Various degrees of sight loss, such as poor night vision, blind spots, and issues with glare, are some conditions of low vision. However, in this case, there isn’t a complete loss of sight or blindness because people can partially see during the day.
In general, low vision is of two types:
1. Legally Blind: In this case, the image is around 20 degrees wide or even less than that. Also, the visual acuity of the patient is over 20/200 with conventional correction.
2. Partially Sighted: The visual acuity of a patient range from 20/70 to 20/200 with conventional lenses.
20/70 and 20/200 are the ratio measurement that describes the person’s vision sharpness or visual acuity. For instance, 20/70 visual acuity represents that a person can see an object at 20 feet to view what a normal person can see at 70 feet.
Though this condition cannot be treated, it can be improved with some suitable visual aids.
Causes and types of low vision
Low vision is caused due to several eye diseases. Sometimes an eye injury can also affect the vision and result in low vision. The macula breaks down can cause loss of central vision, which is known as macular degeneration. Diabetic retinopathy is another condition where the blood vessels become weak and lead to fluid leak into the eye. Sometimes the damage of optic nerve by glaucoma can cause low vision as it is unable to pass messages to the brain.
Here are some of the most common types of low vision:
Central vision loss: A blind spot appears in the center of the person’s vision.
Peripheral vision loss: A person will not be able to view the objects on the side. However, the central vision is not affected.
Night blindness: A person cannot see outside at night or in the poorly lit areas.
Blurred vision: Objects that are far and near appear as out of focus.
Hazy vision: The entire degree of view is glared or appears like it is covered with a film.
What are the Symptoms?
The symptoms of low vision are based on the type of vision loss. However, here are some common symptoms:
● Blank spots
● Dark spots in the vision center
● Blurred or cloudy vision
● Double vision
● Loss of side (peripheral) vision
● Color vision
● Low vision treatment
The restoration of the vision is possible with few eye disorders such as diabetic retinopathy. But, the low vision is permanent. Several visual aids help people with low vision. Some of them are:
● Telescopic glasses
● Lenses that filter light
● Magnifying glasses
● Hand magnifiers
● Closed-circuit television
● Reading prisms
In some cases, people with retinitis pigmentosa may be eligible for the retinal prosthesis. It helps in partially restoring the patient’s vision that has lost their sight. Restored vision lets people to independently do some daily activities like sidewalks, navigate through doorways, sort light, even read large letters and dark-colored laundry.
Some non-optical aids are specially designed for patients with low vision; these non-optical devices include:
● Text reading software
● Check guides
● Talking clocks and watches
● High contrast watches and clocks
● Large print publications
● Phones, Clocks, and watches with enlarged numbers
Visual aids are helpful for several people to improve their sight and quality of life. Low vision condition is preventable for people with diabetes, and few people with glaucoma, and macular degeneration. They can be treated to avoid further vision loss.