Instructions

Astigmatism is a refractive state in which one direction has more blur and requires additional correction. If you have astigmatism, you can use this app to determine your astigmatism angle. While looking at the rings, cover one eye, remove your glasses or contacts, and slowly move away from the screen until it starts to become blurry. If you have astigmatism, the rings will be clear in one direction while being blurry in the opposite direction. Adjust the red line so it passes through the clear direction. The angle displayed is your astigmatism angle.