Abstract
Purpose::
To clarify the influence of death-to-preservation interval (DtPI) on overall corneal graft survival as measured by BCVA, corneal thickness and rejection events after penetrating keratoplasty.
Methods::
We performed a retrospective chart review on 432 keratoconus patients that had received PKP between 1993 and 2003. Inclusion criteria: at least 2 years of follow-up as well as 2 central corneal thickness (CCT) measurements at the following time points: 3 months, 6 months, 1 year, 2 years and 5 years. Other parameters gathered included recipient age, race, sex, donor age, cause of donor death, DtPI, death-to-surgery time, corneal thickness and cell count. A multivariate analysis was performed using donor age, DtPI and cell count as independent variables.
Results::
111 keratoconus patients fit our inclusion criteria. For the 3 month, 6 month, 1 year and 2 year time points, a higher cell count correlated more strongly with a lower CCT than either DtPI or donor age (p = 0.029, p = 0.054 for 3 and 6 months respectively). For BCVA, 5 years after PKP there was a very high negative correlation between DtPI and BCVA (Zero order correlation: -0.61, p < 0.001). The longer the DtPI the higher the corneal thickness readings at the 6 month, 1 & 2 year time points (P= 0.1, 0.2 & 0.4 respectively). We find that DtPT less than 120 minutes had no rejection events and all patients obtained vision equal to or better than 20/25(P=.049).
Conclusions::
Cell count proved to have a higher correlation with a more favorable corneal thickness when compared with donor age and death to preservation interval. Although no association was present initially with BCVA, at 5-year follow-up a significant correlation existed between a better BCVA and a shorter DtPI. In our series, which included a 29% rejection events, there were no rejection events and excellent BCVA outcomes when the death to preservation interval was less than 120 minutes or 2 hours. This suggest that attempting to reduce DtPI on behalf of eye banks and hospitals may prove to provide better corneal tissue and thus may reduce the likelihood of corneal graft rejections, at least in relatively healthy corneas of keratoconus patients. This possibly may be extrapolated to grafts for other conditions. Finally, initial data suggest that DtPI has a weak correlation with overall corneal thickness. A future study with a larger cohort of patients will allow us to further examine the extent of this significance.
Keywords: cornea: clinical science • cornea: storage • transplantation