Opposite clear corneal incisions to correct pre-existing astigmatism in cataract surgery.

In cataract surgery, the clear corneal incision (CCI) has a small flattening effect on corneal curvature, which can be used to reduce pre-existing astigmatism (PEA). Adding an identical, penetrating CCI opposite the first one can enhance the flattening effect. The paired opposite CCIs (OCCIs) are placed on the steepest meridian axis to flatten it. One CCI is used to perform cataract surgery, and the opposite CCI is made to enhance the flattening effect on the cornea to modulate PEA. During the past 12 months, we have used 2.8 to 3.5 mm OCCIs in 33 eyes with PEA greater than 2.00 diopters (D) having cataract surgery. The mean astigmatism correction achieved with this technique was 2.06 D. This technique is simple and effective and yields stable results that rival those of arcuate keratotomy. The OCCI technique has a potential application for the correction of astigmatism in general refractive surgery. Opposite clear corneal incision nomograms with variables such as width, length, and distance from the limbus will be needed for future applications.