Nitty gritty

Eye vision or visual acuity tests are performed to determine the eye's ability to see objects clearly within a certain distance. This test is commonly used as a way to detect eye refractive errors such as minus eye (nearsightedness), farsightedness, and cylindrical eyes. Vision tests can be done by an ophthalmologist, but nowadays there are many available in various optics. Find out the full procedure of the eye vision test here.

Eye check with Snellen chart

Eye vision is usually done when a person has difficulty seeing objects clearly at close, long distance, or both. Children usually do regular vision tests to monitor eye health conditions.

If you have one type of refractive error or myopic eyes, a vision examination aims to determine the strength or thickness of the lens needed to correct (correct) your vision..

Vision tests are generally performed with the help of Snellen chart or a Snellen chart . This chart was developed by an ophthalmologist from the Netherlands, Herman Snellen, in the 1860s.

There are many variations of Snellen chart used in eye acuity tests. In general Snellen chart which is used for the eye test consists of 11 lines of capital letters of varying sizes. The lower the font size, the smaller it will be.

The meaning of the numbers in Snellen chart

Each line of the Snellen chart is accompanied by a number which is a distance (in feet). This figure shows the normal distance a person can clearly read the letters on the line when doing the test.

For example, there is a number 20/200 beside the first row of letters. The first number, 20, represents the distance between you and Snellen chart that is, which is 20 feet or 6 meters away. The eye vision test by reading the letters on the Snellen chart is usually done within 6 meters.

Meanwhile, the second number, which is 200, represents the maximum distance at which your eye is still able to read the letters in the line clearly. The number 200 means, 200 feet or 60 meters. And so on for the numbers listed below.

Assessment of eye vision

According to the American Academy of Ophthalmology, normal human visual acuity in the Snellen chart measure is 20/20 feet or in meters is 6/6 m.

This means that within 20 feet, aka 6 meters, your eyes should still be sharp enough to see writing that is normally legible from that distance.

However, if your eye vision results show 20/40, it means that your eyes with a distance of 20 feet or 6 meters can only read large enough letters that can be read at a distance of 40 feet or 12 meters.

Eye vision examination procedures

Now you understand the basics of the eye vision test. Visual examination can be done in an eye clinic with an ophthalmologist, optician, or nurse. In addition, this test can also be done in optics or a place where glasses and contact lenses are made.

The following is the procedure with an eye acuity test Snellen chart :

• You will be asked to sit or stand 6 meters away from the Snellen card. The examination is usually carried out in a place with bright lighting.
• Close one eye with your hand. If available, you may be dressed in special glasses with an eye patch.
• The doctor or optician will examine the left and right eye separately. The eye with a more blurry vision will be tested first.
• When the eye test begins, you are asked to read the letters from the top of the line down until you are no longer able to read the letters on that line.
• If the eye test does not reach the letters in the 20/20 or 6/6 rows, the procedure will be repeated wearing glasses pinhole . These glasses will attach a corrective lens which is continually replaced until you can see clearly.
• If with pinhole vision has improved, it can be seen refractive errors that occur, whether it is nearsightedness (myopia), farsightedness or cylindrical eyes.
• Step test for reading letters on Snellen chart this will be repeated for the rest of the eye.

Another way to check eye refraction

Usually the eye vision test with Snellen chart enough to judge the acuity of a person's vision. However, in certain cases during the eye exam that you are not able to read the letters that are too faded at all, the ophthalmologist will need to do the examination by hand.

First, you will be asked to count the number of fingers of the examiner from one to six meters away. If you cannot count them, the examiner will move his hand. If you still can't see clearly, the examiner will use a lamp or lighting.

Sharpness check with E chart

Apart from that, Doctor Snellen also created another chart for the acuity test which is for people who cannot read. Especially for children who are not familiar with the complete letters of the alphabet. This chart is also known as E chart .

On the chart for the eye test there is a capital letter "E" facing in different directions. You will be asked to indicate which direction the letter E is facing using your finger. Is the letter E facing up, down, left, or right.

Eye vision examination with chart E will usually be more sophisticated when performed by an ophthalmologist. The chart will be projected like a mirror reflection, you will be asked to see the chart through various lenses. The doctor will continue to change lenses until the eye can clearly see the letter E on the chart.

The same is the case with the vision test using Snellen chart , this eye test can still determine refractive errors such as nearsightedness, farsightedness, and cylindrical eyes. The results of the examination can determine an eyeglass prescription with corrective lenses that is suitable for the vision problem you are experiencing. This test

Examination of refraction or eye acuity is also part of a complete eye exam. We recommend that to find out the condition of eye health, you need to do regular checks.

For children, at least the eye test is done twice a year. Meanwhile, for those of you who are 4o years old or more, do an immediate examination to detect eye disorders or diseases from an early age.