Astigmatism

The very front part of the eyeball is the cornea, which I sometimes liken to a “windshield” over the eye. If there is not perfect radial symmetry of the cornea, we say that there is astigmatism. The most common form of astigmatism is one steep axis perpendicular to one flat axis–sometimes we say this is a “football shaped” eye compared to a “basketball shaped” eye.

We like to try to fix this type of regular astigmatism at the time of cataract surgery. Since making incisions at the time of cataract surgery can affect the astigmatism, one idea to do this is to make incisions at the “correct” spots to minimize astigmatism. However, it turns out that the correction to the astigmatism that is created by an incision is a bit unpredictable. So, it’s an interesting idea, but I don’t use it much.