You may recognise the word astigmatism from a previous eye test — but very few people actually know what it means.The good news? It’s common, manageable, and not a disease . Let’s break it down properly. What Is Astigmatism? Astigmatism occurs when the cornea (the clear front surface of the eye) or the lens inside the eye has an irregular curve — often described as a toric shape . Instead of being evenly round like a soccer ball, the eye is shaped more like a rugby ball.