20/20 Vision: What’s the Big Deal?
You have probably used the expression “20/20 vision” in everyday conversation, heard it on television, and seen it as a requirement for specific jobs, such as pilot or police officer. The concept is closely identified with what many consider perfect vision, so what’s the big deal?
Simply put, the numbers are a measure of visual acuity—in other words, the clarity or sharpness of your vision. The most common method to test acuity is by using what is known as a Snellen chart. It is a familiar white chart with black letters, beginning with a large “E” in the top row and progressively smaller rows of letters beneath. To take the test, you stand 20 feet from the chart (this can be adjusted in optometrist offices) and read aloud up to the smallest set of letters you are able to discern. If you read down to the seventh line, you are considered to have 20/20 or normal vision; that is, the bulk of the population can also see the seventh line at 20 feet. It is possible to have less acute vision, for example 20/40 or 20/100. In the case of 20/40, imperfections in your eyes require you to stand at 20 feet from the chart to see clearly what normal people see at 40 feet. If you have 20/100 vision, you need to stand at 20 feet from the chart to see clearly what normal people see at 100 feet—if you have 20/200 vision, you are considered legally blind.
But that is not the whole story. The two eyes in a pair are not always of equal strength; your right eye may see at 20/20 while your left gives 20/40, still you should see 20/20 (or close to it) with both eyes open. Also keep in mind that acuity is not the only measure of vision; depth perception, focus, and eye coordination are all critical to clarity. Conditions such as myopia (nearsightedness) and hyperopia (farsightedness) play a role as well; it is possible to see things clearly at a distance, but lose focus up close, and vice versa. You can also have better than 20/20 vision, for example 20/15 or 20/10. In this scenario, you would excel the norm and see things at 20 feet that those with 20/20 vision cannot.
If you do not have 20/20 vision and are tired of glasses or contacts as the solution, there is another option. LASIK MD’s laser vision correction procedure will improve your sight over the long term by slightly altering the shape of your eye; correcting astigmatism, myopia, and/or hyperopia. In fact, you may experience results better than 20/20 with LASIK, and the treatment now comes with a 20/20 vision commitment. Your vision can do better, and LASIK can help.