Significant visual impairment that cannot be corrected fully with glasses, contact lenses, medication or eye surgery is termed as low vision. It is caused by severe eye disease, in which visual acuity in the better eye is 20/70 or less, or where there is significant loss of visual field (constriction to 20 degrees or less, termed tunnel vision).
A visual acuity of that a person with 20/70 vision who is 20 feet from an eye chart sees what a person with unimpaired (or 20/20) vision can see from 70 feet away. Low vision can impact people of all ages, but it is associated primarily with adults over the age of 60.
Children with low vision may suffer developmental and educational delays, it is very necessary for early detection and intervention. The low vision examination is a comprehensive evaluation of the person's efficient use of their remaining vision. The purpose of this evaluation is to prescribe optical and non-optical aids to maximize use of the person's residual vision.
These adaptations, called low vision techniques help with everyday tasks.
A thorough eye examination is needed to diagnose causes of low vision. People with low vision may experience the following symptoms:
Low vision cannot be fully corrected. However, there are a wide array of devices to help people with low vision, including magnifiers and reading prisms, large-print reading materials, high-contrast watches, and machines that talk.