The ideal surface of the cornea has a spherical curve, like the shape of a basketball, allowing light rays passing through it to bend toward its center and focus on one spot. Corneal astigmatism is when the corneal surface is shaped more like a football, with flatter and steeper curves. This common condition causes the light rays entering the eye to focus on more than one spot, causing a blur. This blur can most often be corrected with spectacles or contact lenses.
If you have a cataract as well as corneal astigmatism, you may be a candidate for surgical correction of your astigmatism at the same time as your cataract surgery.
Toric Intraocular Lenses (Toric IOL's)
When undergoing cataract surgery, the cloudy lens is removed and a new lens, an intraocular lens (IOL) is inserted in its place. Traditional IOL's clear the vision, but do not correct the underlying corneal astigmatism, so that corrective eyewear or additional surgery would be needed to reduce the blurring or distortion caused by the astigmatism. A toric intraocular lens that can correct corneal astigmatism can instead be inserted at this time, thereby treating the astigmatism and minimizing or often even eliminating the need for astigmatism correction in glasses or contact lenses after cataract surgery.