Out of the five sense organs, our eyesight is one of the most important senses that helps us perceive the reality of things and allow us to connect with our surroundings, keep us safe, and help maintain the sharpness of our minds. While sight is a sensory experience in which light reflects off of shapes and objects which then helps the eyes focus light, vision is how the mind, an aspect of the brain, interprets these images. Together, both sight and vision help to connect people with their surroundings. Hence, it is extremely important to protect the eyes, and promote eyesight as it helps reduce the odds of blindness and vision loss while also preventing eye diseases such as cataracts and glaucoma. Hence as a preventive measure, one must go for regular eye checkups. And one such eye check-up is the Visual Acuity Test.
What Is Visual Acquity Test?
Visual Acuity Test, also known as clarity of vision, is a type of eye examination that mainly checks how well an individual sees the details of a letter or symbol from a specific distance. It usually measures one’s ability to ascertain the shapes and details of the various things that one sees. Visual acuity is just one aspect of the overall vision, while others include peripheral vision, color vision, and depth perception.
Why The Test Is Conducted?
The visual acuity test is a routine part of a comprehensive eye examination or general physical examination, particularly if there is a change in vision or any problem with the vision.
While in children, the test is performed frequently to screen for vision problems since early testing and detection can often help to correct or improve problems related to vision. Undetected or untreated problems may lead to permanent vision damage. This test is often conducted by optometrists, driver’s license bureaus, and many other organizations as a means to check your ability to see.
How Is The Test Conducted?
The visual acuity test can be performed by the two methods: Snellen and Random E testing method.
Snellen Test: The Snellen test mainly employs a chart of letters or symbols of different sizes, arranged neatly in rows and columns. During the test, the doctor or technician asks the person to remove the glasses or contact lenses, sit at a distance of 14-20 feet away and cover one eye. With the opened eye, the person is then asked to read aloud the letters. The same process is repeated with the other eye as well. The doctor typically asks the patient to continue reading smaller and smaller letters until the person can no longer accurately distinguish them.
Random E Test: In the Random test method, the patient mainly identifies the direction of the letter ‘E’. During the test, the person is asked to look into a chart or a mirror reflection through a variety of lenses and point in the direction the letter ‘E’ is facing, i.e., up, down, left, or right. The doctor mainly switches in between the lenses until the chart is clearly visible. This test helps determine the ideal eyeglass or contact lens prescription a person may require to correct the vision.
Who Conducts The Test?
Depending on the type of test and where it is conducted, the visual acuity test can be performed by the following people:
- An ophthalmologist
- An optometrist
- An optician
- A nurse
- A technician
How To Prepare For The Test?
There are no special preparations required for taking the test. The patient just has to go on time and follow the instructions given by the doctor or technician. He or she must also carry any previous eye prescription if required.
How To Interpret The Results?
The visual acuity test result is mainly expressed in the form of fraction such as 20/20; where the upper number refers to the distance the patient stands from the chart which is mostly 20 ft or 6 meters and the lower number indicates the distance at which a person with normal eyesight could read the same line you correctly read.
If the result is 20/20: Your visual acuity at 20 feet away from an object is normal.
If the result is 20/40: You need to be 20 feet away to see an object that people can normally see from 40 feet away.
In that aspect, even if you miss one or two letters on the smallest line you can read, you are still considered to have vision equal to that line.
Well, if your vision is not 20/20, you may need corrective or prescription eyeglasses, contact lenses, or surgery. The result may also indicate an eye condition, such as an eye infection or injury, that needs to be treated. Depending upon the results and physical checkup, the doctor mainly specifies for the best possible treatment to correct the vision.