0 Items ($0.00)

Snellen Eye Chart - 20'

Manufacturer:Graham Field
Unit of Measure: Ea

Item Number:1240

Your Price:   $8.99

Product Description

When checking visual acuity, one eye is covered at a time and the vision of each eye is recorded separately, as well as both eyes together. In the Snellen fraction 20/20, the first number represents the test distance, 20 feet.

The second number represents the distance that the average eye can see the letters on a certain line of the eye chart. So, 20/20 means that the eye being tested can read a certain size letter when it is 20 feet away.

If a person sees 20/40, at 20 feet from the chart that person can read letters that a person with 20/20 vision could read from 40 feet away. The 20/40 letters are twice the size of 20/20 letters; however, it does not mean 50% vision since 20/20 sounds like it is one half of 20/40. If 20/20 is considered 100% visual efficiency, 20/40 visual acuity is 85% efficient.
Snellen Eye Chart - 20' Some images may display non-standard options.

Overall Rating:
0 Reviews  
If you have knowledge of this product, please share some of your thoughts below.

Be the first to review this product, add your review today!

Recommended Bundles
Snellen Eye Chart - 20'
Snellen Eye Chart - 20'
Distance Vision Eye Chart - Illiterate E
Distance Vision Eye Chart - Illiterate E
Customers Who Bought This Item Also Bought
Kindergarten Snellen Eye Chart - 20'
  •  Durable Plastic
  •  Low Glare Matte Finish
  •  Easy to Distinguish Objects

$1695 Ea
Distance Vision Eye Chart - Illiterate E
  •  Durable Plastic
  •  Matte Finish
  •  Green and Red Color Bars

$1295 Ea
JOBST forMen Classic Knee High Support Socks
  •  Bubble-toe and Heel Pocket
  •  Static and Lint Free
  •  Available in 3 Colors

$2390 Pr
Snellen Eye Chart - 10'
  •  Durable Matte Finish
  •  Low Glare
  •  Red / Green Bars

$2549 Ea