Penetrating Keratoplasty After Radial Keratotomy

Abstract

Irregular astigmatism, separation of the radial incisions, and unique wound closure problems have occurred when performing penetrating keratoplasty on eyes that have undergone previous radial keratotomy. To better understand the characteristics of this procedure, penetrating keratoplasty was performed in human cadaver eyes that had previously undergone radial keratotomy. A variety of suturing techniques were tried in order to determine the most effective method of penetrating keratoplasty wound closure. Technical difficulties encountered in performing penetrating keratoplasty after radial keratotomy included: separation of the radial incisions during trephination, resulting in irregular wound edges and peripheral host corneal wound undermining; peripheral host corneal flaccidity with tissue segmentation; poor wound edge apposition; leakage at the junction of radial incisions with donor corneal tissue; and, anterior wound gape of the radial incisions after fixation of the graft with interrupted cardinal sutures. Recommendations made for performing penetrating keratoplasty after radial keratotomy include: the use of preplaced transverse sutures across each radial incision, one 0,5 mm peripheral to the graft wound and the other 1.0 mm from the corneal Hmbus; interrupted radial cardinal sutures between radial keratotomy incisions; meticulous closure of the radial keratotomy-graft wound junctions using a combination of apposition and overlying compression sutures. The double-crossed interrupted and the double-running antitorque suturing techniques were found to be the most effective methods of penetrating keratoplasty wound closure in eyes that have undergone previous radial keratotomy.