Snellen and Tumbling E Non-Reflective Matte Finish Wall Eye Chart Combo Pack_ Size 22 x 11 Inch, Cs411

Cosmid Snellen and Tumbling E Non-Reflective Matte Finish Wall Eye Chart Size 22 x 11 Inch Combo Pack

• The Snellen eye test uses the idea of a subtended 5 minutes of arc with a 20 foot distance. This became the "standard vision" measurement. Also, Snellen developed the idea of a 5x5 grid for a standard for his optotypes. Each optotype must meet certain percentage requirements in this grid before it is used for testing. This helps to make a uniform and equal vision chart. The Snellen eye chart is the basis for many other vision tests.
• The Tumbling "E" vision chart is great for use with patients that are not familiar with the Roman alphabet. These patients simply have to gesture the direction they see the optotype since there is only one. This optotype is place in four different directions; up, down, left, and right. The Tumbling "E" chart is considered highly reliable and accurate. It is great for the detection of Astigmatism.
• Batteries required: False
• Magnification strength: 5.0 multiplier_x