Editor:

We read with great interest the article “Reduction of anterior chamber contamination rate after cataract surgery by intraoperative surface irrigation with 0.25% povidone-iodine,” by Shimada and associates. We congratulate the authors for an excellent article highlighting a simple and novel method by which repeated irrigation of the operative field with povidone-iodine at a concentration of 0.25% achieved an extremely low bacterial contamination rate in the anterior chamber at the completion of phacoemulsification surgery. Techniques to achieve this include preparing the skin with povidone-iodine 10% or 5%, preparing the conjunctiva with povidone-iodine 5% or 1%, and using preoperative topical antibiotic agents. We use topical moxifloxacin 0.5%, 4 times a day 3 days before the surgery, and 15 minutes before the surgery we instill a drop of 2.5% povidone-iodine into the conjunctival cul de sac. We implemented the methodology of Shimada and associates of diluting povidone-iodine to 0.25% with physiologic saline on the day of surgery and irrigating the operative field before and after phacoemulsification and intraoperatively every 20 seconds. Intraoperatively, diffuse punctuate keratopathy occurred in 8 out of 10 patients. One patient developed a large corneal epithelial defect. Though the view became hazy because of corneal haze during the surgery, the surgeon was able to complete all the surgeries. On the first postoperative day the superficial punctuate keratopathy and the corneal epithelial defect had resolved. The methodology of dilution from 5% to 0.25% povidone-iodine was rechecked, with no error noted. It was decided to continue irrigating the operative field with 0.25% povidone-iodine with care taken to avoid spillage over the cornea. With this amended procedure, no corneal epithelial abnormalities were noted intraoperatively.

A study conducted by Jiang and associates has shown grade 1 corneal epithelial damage in a rabbit model with repeated usage of 0.5% povidone-iodine. We observed that repeated irrigation of cornea with povidone-iodine at a concentration as low as 0.25% can be associated with intraoperative superficial punctate keratopathy. We would like to ask the authors if such changes were observed in their patients.