Snellen Eye Charts are named after the Dutch ophthalmologist Hermann Snellen who developed the chart in 1862. In the most familiar acuity test, a Snellen Eye Cart is placed at a standard distance, twenty feet in countries where that is the customary unit of measure. The traditional Snellen Eye Chart is printed with eleven lines of block letters. The first line consists of one very large letter, an E. Subsequent rows have increasing numbers of letters that decrease in size. A patient taking the Snellen Eye Chart test covers one eye, and reads aloud the letters of each row of the Snellen Eye Chart, beginning at the top. The smallest row that can be read accurately indicates the patients visual acuity in that eye.
Wall-mounted Snellen Eye Charts are inexpensive and are sometimes used for rough assessment of vision, e.g. in a primary-care physicians office. Whenever acuity must be assessed carefully (as in an eye doctors examination), or where there is a possibility that the examinee might attempt to deceive the examiner (as in a motor vehicle license office), equipment is used that can present the letters in a variety of randomized patterns. Snellen Eye Charts are the most widely-used piece of equipment by eye care professionals. Buy a Snellen Eye Chart from ActiveForever and test your visual acuity!
Instructions for Properly Administering and Scoring the Snellen Eye Chart Test
Scoring for the Snellen Eye Chart is based on a distance of 20 feet and is represented as a fraction. The numerator is 20 (for the distance) and the denominator is the number listed to the right of each row on the eye chart. They must read the whole line in order to receive that score. The number listed to the right of each line on the Snellen Eye Chart is the normal distance at which people with “normal” vision can read a letter of that row’s size.
For instance, if they can read row 5 of the eye chart but not row 6, their vision would be scored as 20/30, meaning they can read letters at a distance of 20 feet that most people can read at a distance of 30 feet. The Snellen Eye Chart test can also be administered with one eye covered to see if the patient has better vision in one eye over the other.
Contrary to popular belief, 20/20 vision is not considered perfect. It is considered normal for most human beings but it is possible to have vision better than 20/20. If you can read line 8 of the Snellen Eye Chart from a distance of twenty feet, your vision would be scored as 20/10. Some animals, such as hawks, have 20/2 vision.
Snellen Eye Chart Features:
- Used for rough assessment of vision
Snellen Eye Chart Specifications:
- Traditional Snellen Eye Chart - uses the English Alphabet
- Illiterate Snellen Eye Chart - uses different facing Es
- Kindegarten Snellen Eye Chart- uses shapes and objects
- Size: 22" x 11"
- Non-reflective material
- Matte Finish
- Durable Plastic
- 20 ft. Test distance
Returns: All returns subject to ActiveForevers return policy. Please call Customer Service for a RMA (Return Merchandise Authorization) Number. Unauthorized returns will not be accepted.
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