When you go to the doctor for a vision test you’ve probably seen this classic sign, be it in the form of letters, or in the form of “E” jumping all four directions, there are also places to use. image format to make it easier for children to read. And based on the results obtained, the doctor can make conclusions about whether you need to use medicine or if you need to wear glasses.
The standard Snellen board displays 11 rows of capital letters. The first line has a very large letter. Each row then has an even smaller letter size. The person being examined will stand about 6 meters (20 feet) away from the chart and read from it without glasses or contact lenses.
The test will be performed on each eye by covering one eye and reading out the smallest text you can see. The top number refers to the distance in feet you stand from the chart. The bottom number indicates how far a person with normal vision can read the same line that you read correctly. A person with 20/20 vision can see what a normal person can see on an eye chart when they are standing 20 feet away.
Snellen vision test chart.
This table was created by Dutch doctor Hermann Snellen in 1860, along with the 4-way rotating E-table used for children or illiterate people who only need to point their fingers in 4 directions to get results. Later, there are also image tables to be more child-friendly.
Prior to this chart’s release, vision testing was in full swing. The use of the Snellen table helps to systematize and homogenize results across all eye clinics and eyewear manufacturers, This saves a lot of time and money for vision testers as well as eyeglass manufacturers. This was even more important during the industrial revolution in the late 19th century, when jobs required good eyesight more and more.
While this won’t tell your ophthalmologist if you have any eye problems such as glaucoma or retinal problems, it should always be an integral part of any vision exam. .