Posted by: Manhattan LASIK Center
If you have ever had your eyes tested to determine how clearly you can see, you may have heard the term ‘visual acuity’ before. Visual acuity is used to describe the clearness of vision and is expressed as a fraction, such as 20/20 or 20/40. Many people who have heard of these expressions have very little understanding of what they mean but know that 20/20 vision is what is considered to be normal. Here at Manhattan LASIK Center in Paramus, NJ, we take the time to educate our patients and answer any questions. For example:
● If you have 20/20 vision, it means that your visual acuity aka the clearness of your vision is normal when you are 20 feet away from the object that you are viewing.
● However, if you have 20/40 vision, it means that you need to be 20 feet away to be able to clearly see an object that the majority of people can normally see from 40 feet away.
Visual acuity tests normally form part of a standard comprehensive eye test and are performed by asking you to read letters or numbers off of a chart that is a set distance away. This chart is known as a Snellen chart. You may also be referred for a visual acuity test if at any point you have problems with blurred vision. Some professions have strict rules relating to visual acuity and if you fall short of their requirements, you won’t be able to do these jobs – for example, pilots and certain driving jobs.
There is another term that you may hear relating to visual acuity which is referred to as best-corrected visual acuity.
What is Best-Corrected Visual Acuity?
Best-corrected visual acuity refers to the measurement of the best vision correction that can be achieved using glasses or contact lenses. The technique for determining this is the same as standard accuracy, but instead of using your regular eyesight, the score is determined when you are wearing corrective prescription lenses.
For example, if your uncorrected visual acuity is measured as being 20/200, but you can see 20/20 with glasses, your best-corrected visual acuity (or BCVA) is determined as 20/20. This means that using your glasses, your vision is considered normal.
To obtain a driver’s license most states require you to have a BCVA score of at least 20/40.
Your eye doctor in Paramus, NJ will work to find the corrective lens powers that will give you the best possible best-corrected visual acuity. It will be this prescription that is then used in your corrective glasses. Some patients are found to have such a high BCVA score that they are unable to use prescription contact lenses.
Very Poor Best-Corrected Visual Acuity
A person is considered legally blind if their best-corrected visual acuity is 20/200 or worse. This means that even with prescription glasses or contact lenses, the very best that their eyesight can be corrected to is needing to stand 20 feet away from an object to see it clearly when most people can see it clearly from 200 feet away.
For more information on visual acuity testing in Paramus, NJ, or for scheduling your FREE Virtual Consultation, please contact Manhattan LASIK Center at 212-759-9617, and our expert team will be happy to help.