ASTIGMATISM CORRECTING (TORIC) LENS IMPLANTS
The cornea is the clear window over the colored iris, just like the clear quartz over the face of a watch. When the cornea is not round like a basketball, but shaped like a football, that out of round shape causes astigmatism. The optical effect of untreated astigmatism is that some of the rays of light entering the eye through the clear cornea are not focused onto the retina. As shown in the figure below, they come to focus at different planes creating a spread out, fuzzy image when looking at any distance. Because of this, patients with astigmatism often complain of blurred vision, headaches, ghosting, fatigue and eye strain.
Fortunately, astigmatism correcting intraocular lens implants, also called toric lenses, can correct corneal astigmatism. These can be rotated in the eye to offset the magnitude and axis of the corneal astigmatism. Toric intraocular lens implants come in many varieties, such as single focus, depth of focus and trifocal toric lenses. Your doctor will discuss the best option for you based upon your specific eye measurements and your unique lifestyle. Tiny amounts of corneal astigmatism can sometimes be treated with relaxing incisions near the edge of the cornea, making it more round.