Western's Regular 20' Distance Eye Chart is made on non-reflecting, matte finish cardstock with a brass eyelet for wall mounting. This classic visual acuity chart measures 11" wide by 24" high. The Snellen Letters are designed to be read at a standard testing distance of 20 feet. Please Note: A 10 foot viewing distance eye chart is available as well, which is useful when exam room space is limited. The Red and green bars which are printed on this eye chart serve as a reference point during testing and also hint as to a patient's color perception.