A Toric IOL is designed to correct astigmatism. Astigmatism is a factor in some patients’ prescriptions that causes additional blur and distortion. In most cases, it is due to the particular curve of an individual’s cornea; this is called corneal astigmatism.
Prior to cataract surgery, astigmatism is usually corrected with glasses, contact lenses, or laser / LASIK®. After cataract surgery with a traditional IOL, patients with astigmatism would still need glasses or contact lenses to see clearly at all distances.
The advantage of the toric IOL is that corneal astigmatism is addressed at the time of cataract surgery. Therefore, patients with a toric IOL implanted would typically only need help from corrective lenses for near vision, with something as straightforward as reading glasses / magnifiers.
There is a limit to the amount of astigmatism a toric IOL can correct, and for patients with a very significant amount of astigmatism, other treatments such as laser or incisional surgery are combined with the toric IOL to reduce astigmatism.