Astigmatism, if present in either or both eyes, is simply a minute variation in the shape of the front surface of your eye. An analogy would be the difference between a football and a rugby ball. If you have astigmatism then the curvature of the cornea (front of the eye) in different directions varies like that of a rugby ball.
As prescription swimming goggles are used in the pool and not for any detailed tasks then small amounts of astigmatism (denoted by the cyl value of your prescription) do not need to be corrected with the goggles. Instead we calculate the approximate equivalent power of a spherical lens that doesn't correct astigmatism. So, if your astigmatism is less than around 2.50 dioptres and it is not the majority of correction then the standard prescription goggle lenses should be fine
Where the majority of your prescription is astigmatism or you have astigmatism over 2.50 dioptres you may find the goggles aren't as effective for you. In this case if you would like to know whether prescription goggles are likely to be suitable then feel free to contact us.