A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the.
While only a trained eye care professional can properly diagnose vision disorders, using a Snellen chart either at home or in the workplace is both easy and safe. Secure the Snellen chart to a flat surface in a well-lit room.
Facts and history about the eye testing chart. The most commonly used eye chart is known as the Snellen chart. It usually shows 11 rows of capital letters. Free Snellen Eye charts you can print for home or office use to test your eyesight and visual acuity.
The chart should be at a comfortable height, which may change depending on the individual's height. Measure twenty feet from the chart and mark a spot facing the chart directly.
(The test results will only be accurate if it is taken from this distance.) Stand at the twenty foot line and cover your left eye, so you can only see out of your right eye. Starting from the top, read each row from left to right for as far down as you can still make out the letters. Torchlight 2 Mod here. Note the last line on which you could correctly identify every letter. Have an assistant verify that you are reading the letters correctly.
Repeat the test with your left eye, covering your right eye this time. Note the last row you could read with complete accuracy. The row for each eye will not necessarily be the same. Take note of the fraction shown to the left of each row: It identifies how your vision rates. For example, if you could read to the fifth line, you have 20/40 vision; if you could read to the seventh line, you have 20/25 vision.
Look at your results to determine the quality of your eyesight. For example, someone with 20/60 vision can read at 20 feet away what a person with normal vision could read at 60 feet away. In the United States, a score of 20/40 or better is required to drive a car without corrective lenses, vision of 20/200 or worse qualifies an individual as legally blind.
This test may be done in a health care provider's office, a school, workplace, or elsewhere. You will be asked to remove your glasses or contact lenses and stand or sit 20 feet (6 meters) from the eye chart. You will keep both eyes open.
You will be asked to cover one eye with the palm of your hand, a piece of paper, or a small paddle while you read out loud the smallest line of letters you can see on the chart. Numbers, lines, or pictures are used for people who cannot read, especially children. If you are not sure of the letter, you may guess. This test is done on each eye, and one at a time. If needed, it is repeated while you wear your glasses or contacts.