20/20 vision is considered "normal" vision, meaning if you can read at 20 feet (6 meters) the smallest letters on the eye chart that a person with normal vision should be able to read. The number of letters on each row increases moving from top to bottom.

The bottom number is the distance at which a person with normal eyesight can read the same line. Snellen Eye Chart Home use of this Snellen eye chart will help you determine the clarity of your distance vision. The Snellen eye chart is the familiar, classic chart of big and little letters, known as "optotypes" in this case. Other types of commonly used eye charts include the Landolt C, and the Lea test.

20/20 vision. For the Snellen test to be accurate, the chart must be hung 20 feet from the person taking the test. How a Snellen eye chart and a "tumbling E" chart might look at your optician's office.

The Snellen Eye Chart was first created and designed by Hermann Snellen in 1862. The instructions are as follows: "You should stand with your heels 3 metres from the chart in good light, and you can read your Visual Acuity (VA) on the right (numbers on the left if you Their commonalities include the rectangular shape, which dictates that varying numbers of optotypes occur on each line as the space allows. Hermann Snellen designed and used the eye chart to compare and study the Visual acuity, the sharpness and retinal focus. For example, if you have 20/30 vision, it … The normal Snellen chart is printed with eleven lines of block letters.

An eye chart measures visual acuity, which is the clearness or sharpness of vision.

The Snellen eye chart was first designed by a Dutch ophthalmologist, Herman Snellen in 1860s.

Below you will find several variations of printable Snellen eye charts you can download and print for home use to determine your visual acuity ie. There are two sets of numbers in a Snellen chart value: the numerator, the number above, and the denominator, the number below.

Refractive errors are best corrected using the patient's glasses but can be improved using a pin hole.

The chart consists of 11 lines of block letters, beginning with a large single letter on the top row.

Many variations of the Snellen chart exist today. A person taking the …

The Snellen chart (see image) is the most commonly used eye chart by health care professionals. If the room can’t accommodate this, mirrors may be used to simulate a distance of 20 feet, All About Vision explains 2.The standard point of reference, 20/20, is not the best vision possible, but a reference point for what an average person can see at a distance of 20 feet. The attached chart should be printed into a A4 page and use from 3 metres as a starting point before deciding whether a driver's sight should be tested properly. The top number is your distance in feet from the chart. Read more about Hermann Snellen and the Snellen Eye Chart on Wikipedia. The original Snellen chart had a rectangular shape with seven rows of letters printed progressively smaller as you move down the chart. The first line consists of one very large letter, which may be one of several letters, for example E, H, or N. Subsequent rows have increasing numbers of letters that decrease in size.

The result of the Snellen's chart is expressed as two numbers: the distance from the chart (usually 6 m or 20 ft) and the distance at which the letter the patient could read should be read at. Published: 2009-08-30 | Last updated: 2009-08-30. Many Snellen charts do not contain lines of small letters and are truncated to 6/4, 6/4.5, 6/5 or even 6/6. This is best done using a Snellen's chart; alternatives include a near-vision chart. This can be useful to screen children for nearsightedness, which causes blurry distance vision. The tumbling E chart tests the visual acuity of young children and others who can't read letters aloud. Determination.

The numerator stands for the distance between the patient and the chart, which is ideally 20 feet away.

The chart also can help you determine if you meet the legal visual acuity requirement for a valid driver’s license (20/40 in most states). The majority of Snellen charts have one 6/60 letter, two 6/36 and three 6/24 letters, whereas logMAR charts have five letters on each of these lines and additional lines of letters at 6/48 and 6/30.