Comparative efficacy of single and double povidone-iodine soaking protocols combined with draping sequence in donor cornea disinfection.

PURPOSE: To evaluate the effectiveness of three povidone-iodine disinfection protocols on donor corneoscleral rim contamination and to identify factors influencing microbial contamination during corneal procurement.

DESIGN

Prospective interventional study.

METHODS

This single-center study at the National Eye Bank of Taiwan included 830 corneas from 440 donors. Three povidone-iodine protocols were compared: soaking after draping (single-soaking method 1 [SSM1]), soaking before draping (SSM2), and soaking both before and after draping (double-soaking method [DSM]). Corneoscleral rim cultures were obtained post-procurement, with conjunctival cultures performed before and after each disinfection step in DSM. Grafts with gentamicin-resistant isolates were re-cultured after hypothermic storage. Donor and procurement variables were analyzed for association with contamination. The primary outcome was rim contamination; secondary outcomes included conjunctival culture positivity, persistence of resistant isolates, and associated risk factors.

RESULTS

Of 830 corneas, 350 underwent SSM1, 364 SSM2, and 116 DSM. Rim contamination rates were similar (SSM1: 3.1%, SSM2: 3.0%, DSM: 2.6%; P > 0.05). In DSM, conjunctival positivity significantly decreased from 36.1% to 19.8% after double-soaking ( P < 0.001). Staphylococcus epidermidis was the most frequent isolate. One gentamicin-resistant strain was identified but did not persist after storage. No donor or procedural factors correlated with rim contamination, and no post-transplant infections occurred.

CONCLUSION

Double-soaking significantly reduced conjunctival microbial load and showed a favorable trend toward reducing rim contamination. These findings support its use as a simple, low-risk strategy to lower ocular surface bioburden and enhance graft safety, while confirming the effectiveness of current disinfection and storage practices.