Comparison of Povidone-Iodine and Gentamicin Soak as Scleral Buckle Infection Prophylaxis

Objective: To determine the best method of antimicrobial prophylaxis against implanted material-associated infections in the setting of scleral buckle surgery.

Design: Experimental study.

Participants: Scleral buckle elements were soaked in either gram-positive or polymicrobial broth, while control buckle elements were soaked in PBS only.

Methods: Solid silicone and sponge scleral buckle elements were inoculated with common pathogens of the ocular surface, and then soaked in either 1% or 5% povidone-iodine, 1 mg/mL gentamicin solution, or sterile saline for 1, 5, 10, or 15 minutes. Bacteria were then isolated from the buckle elements and cultured for 24 hours.

Results: In all gram-positive bacterial conditions, gentamicin solution decreased the bacterial load from 451,666.67 colony-forming units (CFU)/mL to 171,611.11 CFU/mL (p=0.0004). The fractional bacterial survival after soaking in gentamicin was higher for the silicone sponge than band (0.357 vs 0.079, p=0.038). Both 1% and 5% povidone-iodine were able to completely eradicate all gram-positive bacteria of both buckle elements. Only 5% povidone-iodine was able to completely sterilize all microbes on the buckle after soaking in a polymicrobial solution consisting of gram-positive, gram-negative bacteria, and fungi.

Conclusion: Povidone-iodine solution was significantly more effective at bacterial eradication compared to gentamicin solution. For all scleral buckle procedures, we recommend soaking the buckle element in 2-3% povidone-iodine solution before placement and rinsing the ocular surface with the same solution after placement.