Though the term is a common one, many people still wonder, “What is 20/20 vision?” Most people understand that it means that their vision is good, but the definition of the term is not something with which they are acquainted. Here, we clear up the confusion.
20/20 refers to a person’s visual acuity, denoting that it is normal. This does not mean that the person’s vision is perfect; it just gives an idea of the ability to see symbols and objects from a distance. The numbers indicate two things: the top number is the distance that the person being tested stands from the eye chart, and the bottom number represents how far away a person with normal vision could stand and still be able to read the letters in that line of the chart.
In other words, if you have 20/10 vision, it means your vision is better than average, because you can read from twenty feet what the average person would have to move ten feet closer to read. Conversely, if you have 20/200 vision, your vision is poor, because you have to be twenty feet away from the chart to read what someone with normal vision could read from two hundred feet. It does not matter if the doctor’s office is not big enough for you to stand twenty feet away, because the system operates on a system of ratio.
The chart used is typically the Snellen eye chart. Developed in 1862 by Dr. Herman Snellen, a Dutch ophthalmologist, it is the original eye chart. Since its creation, other tests have been developed, some for children, or adults who cannot read. None of those is as commonly used as the Snellen chart.
If you have 20/20 vision, you may still have vision problems. You can still have trouble seeing close objects, or you may have difficulty focusing, or poor depth perception or peripheral vision. Your doctor will test your eyes separately and together, and some people have a different score for each eye. Once your visual acuity is determined, your doctor can decide which course of action is best for you, whether glasses, contacts, or LASIK.
If you are in need of glasses and considering LASIK, contact Tylock Eye Care and Laser Center. With twenty years of Dallas LASIK experience, their dedicated staff combines a commitment to excellence in patient care with the best in state of the art technology. This allows them to provide patients with the absolute best standard of care. Check out their website to learn how their team of professionals can help you achieve your best possible vision.