VISION TESTING FOR ASTIGMATISM

摘要

Disclosed are computer implemented methods for testing astigmatism which display differently coloured bars against a contrasting background. In one implementation, parallel coloured bars are separated and joined through various angles of rotation against a constant background. In another implementation one set of bars is formed by variable grating pattern which is rotated within an annulus of solid colour bars, desirably against a contrasting intermediate background and a reference background having a linear grating pattern.