Visual acuity is commonly measured using a Snellen chart. This eye chart, developed by Dutch ophthalmologist Herman Snellen in 1862, features rows of letters that decrease in size. During an eye exam, you stand a standard distance away, typically 20 feet (or 6 meters), and read the smallest line of letters you can discern. This measurement helps eye care professionals understand how clearly you see, impacting daily activities like reading, driving, and recognizing faces.
Understanding 20/63 Vision
When an eye care professional states your vision is 20/63, it refers to a specific measurement on the Snellen scale. The first number, “20,” represents the distance in feet you stood from the eye chart during the test. The second number, “63,” indicates that what you can clearly see at 20 feet, a person with 20/20 vision can see from 63 feet away. This means your vision is less sharp than average.
A visual acuity of 20/63 signifies a mild vision impairment. While noticeably worse than 20/20 vision, it is not considered legally blind, which is defined as 20/200 or worse in the better eye with best correction. For daily life, 20/63 vision might mean difficulty reading street signs until closer, struggling to see details on a television from a distance, or finding it challenging to recognize faces across a room.
Factors Contributing to 20/63 Vision
Several common eye conditions can lead to a visual acuity of 20/63. Refractive errors are a primary cause, occurring when the eye’s shape prevents light from focusing correctly on the retina. These include myopia (nearsightedness), where distant objects appear blurry, and hyperopia (farsightedness), where close-up objects are blurry. Astigmatism, another refractive error, causes blurry or distorted vision at all distances due to an irregularly shaped cornea.
Other eye conditions can also contribute to reduced visual acuity. Cataracts, which involve clouding of the eye’s natural lens, can scatter light and lead to hazy vision. Age-related changes, such as presbyopia (age-related farsightedness), can also affect near vision, making it harder to focus on close objects, particularly after age 40.
Managing 20/63 Vision
Improving 20/63 vision often involves effective solutions. The most common approach is the use of corrective lenses, such as eyeglasses or contact lenses. These lenses reshape how light enters the eye, directing it accurately onto the retina for clearer vision. For many, obtaining the correct prescription can restore vision to 20/20 or better.
Surgical options may also be considered, especially if refractive errors are present or if other conditions like cataracts exist. Procedures such as LASIK or PRK can permanently alter the cornea’s shape to correct refractive errors. If cataracts are the underlying cause, cataract surgery involves removing the cloudy lens and replacing it with a clear artificial intraocular lens, which can significantly improve vision. Consulting an eye care professional is important for an accurate diagnosis and a personalized treatment plan.