• progressive keratoconus
• penetrating keratoplasty
• compression sutures
• host cornea thinning

A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Early postoperative astigmatism following penetrating keratoplasty (PK) may occur more frequently in keratoconus than other conditions, although all corneal grafts are beset by this problem. This may occur despite meticulous surgical technique; optimising graft centration, tissue distribution, and suture placement. A myriad of different suture adjustment regimens have been described for minimising early postoperative astigmatism. If significant astigmatism remains, which cannot be corrected by optical means, then further surgical procedures may be utilised to reduce the astigmatism. Relaxing incisions, arcuate keratotomy, and transverse keratotomy are flattening procedures that may be performed in the steep meridian. Compression sutures and wedge resection are steepening procedures that may be performed …