Characterization of Corneal Endothelial Injury During Penetrating Keratoplasty.

Purpose: To characterize corneal endothelial injury during penetrating keratoplasty in a controlled wet laboratory environment using human tissue. To identify potential areas or steps within surgery in which insult to the corneal endothelium may be most affected by trauma during routine penetrating keratoplasty.

Methods: Human donor corneas (n = 12) with intact endothelium underwent experimental penetrating keratoplasty. Endothelial injury was evaluated after each suture quartile using trypan staining, a validated modality for assessing endothelial injury. Insult was quantified using high-resolution photography and computer software.

Results: Statistical significance was found in the change in staining between quartiles as determined by repeated-measures analysis of variance (F3,11 = 5.83, P < 0.0044). A post hoc Tukey test indicated that the change in staining during the first quartile (3.38% ± 0.5%) was significantly lower than the remaining quartiles at P < 0.021. The change in staining did not differ significantly between the second (8.36% ± 1.2%), third (7.88% ± 1.2%), and fourth (7.73% ± 0.9%) quartiles at P > 0.97.

Conclusions: Evidence from this investigation suggests that injury to the endothelium occurs most during the second quartile. This may be a promising area in which clinicians could target their efforts to avoid injury to this vital tissue layer for best surgical outcomes and graft longevity.