Patent ID: 11944383
Assignee: CARL ZEISS VISION INTERNATIONAL GMBH
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 0:
1. An apparatus for determining a refractive error of an eye, the apparatus comprising:
a camera configured to capture an image of light from the eye; and
an optical power changing device configured to vary an optical power of a light path from the eye to the camera,
wherein the apparatus includes a computing device which is configured to calculate the refractive error of the eye based on a series of images of light from the eye captured by the camera with varying optical power using the series of images directly as at least approximate point spread functions,
wherein the point spread function is an intensity distribution resulting from the eye being illuminated in a single spot, and
wherein the computing device, for calculating the refractive error, is configured to determine a modulation transfer area as a function of meridian angle and optical power in an angle range from 0° to 180° based on the series of images, and to calculate the refractive error based on the modulation transfer area as a function of angle and optical power.