Sources of Error in Keratotomy Knife Incision

Since the introduction of anterior radial and astigmatic keratotomy in the late 1970s, significant attention has been placed on the pachymetric measurement with three different modalities. Pachymetry is only one factor related to the attained depth from the keratotomy incision. Micrometer gem knife footplate design and cutting edge quality provide far greater potential sources of error than involved in the simple measurement of corneal thickness. Micrometer accuracy, chuck stability, footplate design, alignment relationships, blade quality and care, and the precision of the calibration device all can contribute significantly to the accuracy of the incision.