An eye refractive power measuring apparatus having a unit for projecting a plurality of index images onto the fundus of an eye to be examined, a unit for detecting the eye fundus reflected light beams of the index images correspondingly to each measuring meridian direction, a unit for operating the refractive...http://www.google.com/patents/US4755041?utm_source=gb-gplus-sharePatent US4755041 - Eye refractive power measuring apparatus
