Effect of operative field irrigation on intraoperative bacterial contamination and postoperative endophthalmitis rates in 25-gauge vitrectomy.

Purpose: The purpose of this study was to compare bacterial contamination and endophthalmitis rates with different irrigation methods in 25-gauge vitrectomy.

Methods: A total of 4,347 eyes undergoing 25-gauge vitrectomy were studied prospectively. Of these, 2,801 eyes were irrigated with infusion fluid (group A) and 1,546 with 1.25% povidone-iodine (group B) after lid speculum placement. Bacteriologic culture was performed for 103 eyes in group A and 155 eyes in group B using the following samples: ocular surface fluid after placement of the lid speculum (left eye 1), ocular surface fluid after operative field irrigation (left eye 2), vitreous collected after angled incision made while some irrigation fluid remains in the conjunctival sac (V1), and vitreous at the completion of vitrectomy (V2).

Results: The bacterial contamination rate in left eye 1 did not differ significantly between groups A (5.5%) and B (5.8%). However, the rates in left eye 2, V1, and V2 were lower in group B (0%, 0%, and 0.6%, respectively) than in group A (2.0%, 1.0%, and 2.0%). Incidences of endophthalmitis were 0 of 2,801 eyes and 0 of 1,546 eyes in groups A and B, respectively.

Conclusion: After lid speculum placement, ocular surface contamination occurred in approximately 6% of eyes. Irrigating the operative field again with 1.25% povidone-iodine and performing sclerotomy with some povidone-iodine remaining in the conjunctival sac prevented bacterial contamination of the vitreous.