Device for determining astigmatism of eye using crossed-cylinder method divides region viewed by eye into two adjacent, simultaneously visible sub-regions with inverted axis positions

摘要

The device has an image divider (9) that divides a region (12) viewed by the eye (11) under investigation into two adjacent, simultaneously visible sub-regions (13,14). The first sub-region is visible through a crossed-cylinder lens element for a first cylinder axis position and the second through a crossed-cylinder lens element for a second axis position, whereby the two cylinder axis position are mutually inverted. Independent claims are also included for the following: a method of determining astigmatism of the eye.