Visual Acuity, Vision Impairments and Low Vision
What are the medical terms for nearsightedness and farsightedness?
- The medical term for nearsightedness is myopia, correctable with glasses, contact lenses or, in some cases, refractive surgery (LASIK or Corneal Ring Implants).
- The medical term for farsightedness is hyperopia, correctable with glasses, contact lenses or, in some cases, refractive surgery.
- Related conditions (also correctable with glasses or contact lenses) include astigmatism and presbyopia.
What Is visual acuity?
Acuity is the measure of the eye’s ability to distinguish the smallest identifiable letter or symbol, its details and shape, usually at a distance of 20 feet. This measurement is usually given in a fraction. The top number refers to the testing distance measured in feet and the bottom number is the distance from which a normal eye should see the letter or shape. So, perfect vision is 20/20. If your vision is 20/60, that means what you can see at a distance of 20 feet, someone with perfect vision can see at a distance of 60 feet.
What Is legal blindness?
You are legally blind when the best corrected central acuity is less than 20/200 (perfect visual acuity is 20/20) in your better eye, or your side vision is narrowed to 20 degrees or less in your better eye. Even if you are legally blind, you may still have some useful vision. If you are legally blind, you may qualify for certain government benefits.
What Is visual impairment?
If neither of your eyes can see better than 20/60 without improvement from glasses or contacts, you may be defined as visually impaired. In addition, poor night vision, limited side vision, double vision and loss of vision in one eye may also determine visual impairment.
What Is low vision?
Low vision is a term describing a level of vision below normal (20/70 or worse) that cannot be corrected with conventional glasses. Low vision is not the same as blindness. People with low vision can use their sight. However, low vision may interfere with the performance of daily activities, such as reading or driving.
Can eyes be transplanted?
No. Currently, there is no way to transplant a whole eye. However, corneas have been successfully transplanted for many years.