US Patent 7677727 Eye refractive power measurement apparatus

An eye refractive power measurement apparatus capable of performing analysis of an examinee's eye for irregular astigmatism with accuracy comprises a measurement optical system comprising an optical system projecting measurement light onto an examinee's fundus and an optical system photo-receiving the measurement light as a ring or substantially-ring fundus reflection image, a light deflection member placed in the optical systems, a unit rotating the deflection member, a memory storing the photo-received image as a measurement image, an analysis unit performing analysis of the measurement image, and an output unit, wherein the analysis unit detects the number of images or a width of an image in each meridian direction in the measurement image and judges the eye has irregular astigmatism when a portion in which the number of the images is two or a portion in which the width of the image goes beyond a predetermined level is detected.