Eye Care is one of the most important parts in the practice of Optometry. Good eye care practices are both the responsibility of patients and doctors. This series of posts will cover the basics that highlight important topics in Optometry to show how eye care is important.
One thing most people know about optometry is that 20/20 vision is good to have. It means that at a distance of 20 feet, objects are seen clearly and crisply. If an Optometrist were to say you had 20/100 vision, that would mean that you would have to stand 20 feet away from an object while someone with normal vision could stand 100 feet to see the object just as clearly.
I tend to find pictures help explain this. In the above image, the man has 20/100 vision. He has to stand 20 feet away from the vase on the table while the woman can stand 100 feet away and see the same clarity as the man. The 20/(number) figure that is given by Optometrists part of what is known as "visual acuity."
The reason why everyone doesn't have 20/20 vision is due to a variety of reasons including nearsightedness (blurry distance vision), farsightedness (blurry close-up vision), astigmatism (non-spherical eye) or eye disease. Optometrists will be able to determine the causes during a comprehensive eye exam. The way to check distance vision is generally done by reading lines off those famous eye charts. Because of there are many factors for differences in visual acuity, that could mean that even people with 20/20 vision will note their vision could use adjustment.
The most common way to correct distance vision by prescribing glasses or contacts. There are also visual therapy programs and medications that can help improve vision, when the situation calls for them. Since the eyes are rapidly changing all the time, annual eye exams are important to make sure that visual corrections are current and aiding the health of the eye.
20/20 vision is a good barometer for healthy vision as it tests distance and clarity; however, it is only one part in the story. Saying someone has "perfect" sight when they have 20/20 vision is entirely misleading. What is missing are the other indicators of optimal vision like peripheral (side) vision, coordination of the eyes, depth perception, ability to focus and color testing. In summary, 20/20 vision is important but it isn't the end all, be all measurement for healthy vision.