Evaluation of Posterior Wound Profile After Penetrating Keratoplasty Using Anterior Segment Optical Coherence Tomography

Purpose: To study the wound configuration after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography. Methods: All post-PKP patients who were examined at the Cornea Services of the Royal Victorian Eye and Ear Hospital, Melbourne, between February and November 2008, were enrolled in the study. The wound profile was studied using anterior segment optical coherence tomography. Results: A total of 159 graft-host sections from 29 eyes (24 patients, mean age 57 +/- 20 years) were analyzed. Cases with remaining sutures were excluded from the study. The majority of patients included were operated for keratoconus (16 eyes, 55%) followed by endothelial dysfunction (8 eyes, 27.6%). The anterior graft-host junction was smooth in all the scans. Internal graft-host aberrations were observed in the form of host "ledge" (100 scans, 62.9%) and graft-host "steps" (59 scans, 37.1%). Steps were identified by a change in the curvature of the posterior surface of graft-host junction. Ledges were defined by the presence of a rim of extra corneal tissue in any of the quadrants that were protruding into the anterior chamber. Patients with keratoconus (34 ledges and 22 steps) had more host ledges, whereas those transplanted for endothelial dysfunction (12 ledges and 33 steps) had more steps. Graft over sizing revealed an increased trend toward the occurrence of steps. Although statistically nonsignificant, cases with higher astigmatism seemed to have more steps (4.31 +/- 3.39 diopter) than ledges (1.75 +/- 1.87 diopter) (P = 0.36). Conclusions: After PKP, the posterior graft-host malapposition occurs commonly and may be related to the original corneal pathology.