Most people have an idea of what 20/20 vision means, even without speaking to a LASIK surgeon in Orange County. However, this measurement of visual acuity is not always understood in the fullest context, which fuels the common misconceptions that people have about eyesight and vision correction. In order to bridge the gap of information, LASIK eye specialists are here to explain how vision sharpness is measured in the medical field and what that means for people who want to improve their current eyesight.
If you’ve ever had an eye examination, then you’re familiar with the letter chart that most clinics use to judge a person’s visual acuity. The characters get smaller on each line, all the way down to the bottom. An eye doctor can measure the strength of your eyesight based on how far down the chart you can clearly read.
These letter charts are named after Dr. Herman Snellen, the Dutch ophthalmologist who first started integrating them into medical practices. Snellen eye charts are standardized in format and size. Visual acuity correlates to the lines of the chart and is written as a fraction.
When you see 20/20, the two numbers represent different aspects of the Snellen refractive test. The first one (the top of the fraction, or the numerator) is the distance of the chart from the patient. So, in the case of 20/20 vision, the doctor has measured 20 feet of viewing distance. Since not all examination rooms have 20 feet of space, many doctors will utilize a mirror system to simulate this distance.
The second number (the bottom of the fraction, or the denominator) represents the smallest line that the patient can read. The top row is usually measured as 20/400, and the number decreases from there. This explains why 20/20 vision is better than 20/30 or 20/40. However, the smallest line does not stop at 20/20. While many people believe that 20/20 is perfect vision, it is actually just a baseline of good vision for the general population. The Snellen chart has lines that reach 20/15 or 20/10.
Visual acuity can be important for many different careers and lifestyles. Those who wish to serve in the military or become a pilot need 20/20 vision and civilians who want to obtain a driver’s license need 20/40. Orange County LASIK clinics have helped many people achieve their vision goals through laser eye surgery.
There are other factors that contribute to vision strength, besides visual acuity scores. Some of these optic elements include eye coordination, color vision, visual perception, binocular vision, and eye focusing. When you visit a surgeon, they will be able to determine the exact issues that your eyes are facing and recommend a procedure that will most benefit you.
Understanding visual acuity is the first step to confronting your vision problems and taking the proper steps to correct them. You can schedule an appointment with an Orange County LASIK surgeon like Doctor Moosa to get a thorough eye examination and consultation. Now that you understand the basics of 20/20 vision, you can ask the right questions and strategize with an eye care professional to achieve the vision you’ve always wanted.