Corneal wound malapposition after penetrating keratoplasty: An optical coherence tomography study

Aims: To examine the wound configuration after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography (OCT). Methods: All PKP patients who were examined for routine follow-up, between November and December 2006, after having all their sutures removed were included. Patients underwent clinical examination, refraction, corneal topography, aberrometry and Visante anterior segment OCT. Results: 204 graft-host sections from 27 eyes (25 patients, mean age 51.6 (SD 17.7) years) were analysed. Although all the graft-host junctions had continuous smooth epithelial surfaces, 124 of them (60.8%) had internal graft-host malappositions such as gapes (15.7%), steps (30%) or protrusions (15.2%). Keratoconus patients had significantly more graft steps (p<0.05) while those transplanted for endothelial dysfunctions had more protrusions (p<0.01). Graft oversizing significantly increased the size of malappositions. Internal gapes or steps significantly reduced the graft-host touch. Intraocular pressure (IOP), final refraction and final keratometric cylinder were all significantly correlated with the presence and size of the malapposition, while steeper keratometry and tilt aberrations correlated with diminished graft-host touch. Conclusions: After PKP, internal graft-host malapposition is relatively common and associated with increased ametropia, astigmatism, IOP and optical tilt aberrations.