Betts Ready to Read Test 3A: Two-Eyed Efficiency (Keystone Stereoview #35082)
Keystone View Company (Meadville, PA) published several series of stereoscopic images promoted as optical diagnostic and therapeutic tools in the 1930s and '40s—including the "Eye-Skill Series," "Comfort and Depth Perception Series," and "Telebinocular Tests of Visual Efficiency."
This stereograph appears in several of Keystone's optical series; this particular card belonging to the "Betts Ready To Read Tests," one of the stereoscopic complements Betts' book, The Prevention and Correction of Reading Difficulties. Keystone/Betts stereoscopic series of telebinocular tests were commonly used by schools as a screening device for vision dysfunction—much to the chagrin of the American Medical Association, which found the test over-diagnosed vision impairment and deemed it "unacceptable."
Card slightly bowed, otherwise VG; 3.5 X 7 inches. Housed in mylar sleeve for safekeeping.