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but prior to surgery. The conclusion that 10.0% was more effective than 1.0% and 5.0% was based on the culture results. This culture was not accurate, as I will explain, and thus led to an incorrect conclusion. When obtaining cultures while povidone–iodine is still present, the swab must be exposed to sodium thiosulfate to inactivate the iodine. If not inactivated, the iodine will continue to kill bacteria on the swab and in the culture. Because the culturewas not exposed to sodium thiosulfate, the testing showed fewer colonies with the higher percentage povidone–iodine. The study found that at the end of surgery, there was no significant difference in the rate of positive cultures in the 3 groups (1.0%, 5.0%, and 10.0%). Based on this finding and considering the risk of toxicity with povidone–iodine 10.0%, it is best to use the lower percentage solutions. Kill-time studies have demonstrated that lower percentage solutions are more effective at killing bacteria. In other words, 1.0% is more effective than 10.0%. This inverse relationship is based on the presence of higher free iodine parts per million at lower concentrations, and it is the free iodine that kills the bacteria. The toxicity associated with povidone–iodine 10.0% is harmful and not necessary. Successful prevention of endophthalmitis has been demonstrated with a povidone–iodine 1.0% solution. The only method that has been shown to render the anterior chamber free of bacteria is the use of povidone–iodine 0.25% irrigation during cataract surgery. By using the povidone–iodine irrigation during surgery, any bacteria that enter the surgical field intraoperatively are being killed and the eye can be irrigated at the conclusion of surgery, keeping the number of bacteria to a minimum. I have used this technique in over 3000 cases and have had no cases of endophthalmitis. I urge ophthalmologists to adopt the practice of intraoperative irrigation with povidone–iodine 0.25%. I also encourage eye surgeons to prep the skin, lids, and lashes with povidone–iodine 5.0% or 2.5%. Because of toxicity, irrigation with povidone– iodine 10.0% should be avoided.