Astigmatic keratotomy

Abstract

Astigmatic keratotomy (AK) is performed for correction of corneal astigmatism and may be performed during cataract surgery, post-cataract extraction, or post-PKP. AK corneal incisions are performed more centrally in the cornea as opposed to limbal relaxing incisions (LRI). In this technique, a coupling phenomenon is seen in which there is a flattening of the incised steep meridian, accompanied by steepening of the unincised meridian 90° away. Prior to AK, confirmation of corneal astigmatism with manual keratometry, evaluation of corneal topography to identify irregular astigmatism, and pachymetry at sites of planned incision(s) to avoid corneal perforation should be performed. AK has been proven to be a convenient, practical, and cost-effective way of managing astigmatism.