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

Claim 18:
19. A method for determining a refractive error of an eye, the method comprising:
capturing a series of images of light from the eye with varying optical power in a light path from the eye to a camera used for capturing the series of images; and
calculating the refractive error of the eye based on the series of images using the series of images as at least approximate point spread functions by determining an optical power where the point spread function is sharpest for at least three meridians, and calculating the refractive error based on the optical powers where the point spread function is sharpest determined for the at least three meridians,
wherein determining the optical powers where the point spread function is sharpest comprises calculating modulation transfer function areas for each of the at least three meridians; and
determining the optical power where the point spread function is sharpest as an optical power at a maximum modulation transfer function area for the respective meridian.