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What is the Visual Acuity Test, and Why is it Conducted?

What is the Visual Acuity Test, and Why is it Conducted?

Vision Health


A visual acuity test can be considered part of an all-inclusive ophthalmologic examination. The primary aim of this test is to verify the visual sharpness or clarity of the patient’s vision. This test is carried out by checking the patient’s ability to make out different stylized symbols or letters from a standard distance. This article provides a comprehensive guide to the process.

What Is a Visual Acuity Test?

This test is an eye exam that inspects how well you can see the minute details of a symbol or letter from a certain predetermined distance.

In other words, visual acuity points to your ability to distinguish the shapes and minute details of the objects you see. However, keep in mind that visual acuity is just one factor that affects your overall vision. Other factors determining your vision's clarity include peripheral vision, color vision, and depth perception.

Also, note that there are various types of visual acuity tests. However, most of these tests are very simple. Additionally, keep in mind that a visual acuity test can be conducted by an optometrist, an optician, an ophthalmologist, a nurse, or a technician depending on the situation. There are minimal risks associated with a visual acuity test, and these generally do not require any special preparation.

The Key Purpose Visual Acuity Test

The obvious symptom you may develop, which tells you to undergo a visual acuity test, is when you experience vision problems or feel your vision has changed. Visual acuity tests are part of a comprehensive eye exam, and it is good if children take these tests frequently. That’s because a visual acuity test will help detect vision problems early and prevent the problem from getting worse. A visual acuity test is mandatory in certain situations, such as applying for a driving license or hoping to work for other organizations where having a good vision is important.

How Is the Visual Acuity TestDone?

There are mainly two types of visual acuity tests performed as given below:

  • Snellen

This test uses a chart of symbols or letters to test your vision. You might have already seen this chart in an ophthalmologist’s office or a school nurse’s office. In this chart, various letters of different sizes are placed in rows and columns. When you view this chart from a distance of 14 to 20 feet away, it helps your doctor determine how good your vision is.

First, you will be asked to sit or stand a certain distance away from the chart and cover one eye for this test. Next, you’ll need to read out the letters in the chart aloud with your uncovered eye. You’ll need to repeat the same process with your other eye. Typically, your eye doctor will ask you to read a set of letters, each smaller than the previous one. This will go on until you can no longer clearly distinguish letters.

  • Random E

This is also another test used to check your visual acuity. In this test, you will have to identify the direction the letter “E” faces. Here, merely looking at the letter on a chart or projection, you have to point in the right direction the letter is facing. That is whether the letter E is facing: down, up, left, or right.

Also, remember that these tests tend to be more intricate when performed at an eye clinic when compared to doing it in a nurse’s office. That’s because the chart may be shown as a mirror reflection or projected at an eye doctor's office. You will also get to look at the chart through different lenses. 

The lenses will be switched many times by your doctor until he is sure that you can see the chart clearly. This helps your doctor prescribe the correct contact lenses or ideal eyeglass if you require vision correction. So, always prefer an eye doctor's office when you want to test your vision.

Visual Acuity Test Results

A person’s visual acuity is depicted as a fraction, e.g., 20/20 or 20/40. A 20/20 score means that you have a normal visual acuity at 20 feet distance from an object. Let’s say if your score is 20/40. It indicates that you have to be 20 feet away to see an object that normally people can view from 40 feet away.

See Also: Frequently Asked Questions About Vision Health

Do you think your vision is deteriorating even after wearing prescribed glasses or contact lenses? Then you might want to get an acuity test or test of vision conducted in an eye care hospital. Contact us at Netralayam, the best eye care hospital in Kolkata. It's one of the best eye hospitals near you to get a visual acuity test done. 



The mission of Netralayam is to provide tertiary level superspeciality eye care service of highest quality to all sections of the society through a team of competent, committed and compassionate professionals in a patient-friendly environment.

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