title: The challenge of determining aqueous contamination rate in anterior segment intraocular surgery.
abstract: OBJECTIVE
  To determine aqueous contamination rate in anterior segment intraocular surgery using two different techniques of obtaining aqueous fluid and to assess whether a 3-day application of topical 0.3% ofloxacin reduces this contamination rate compared with a 1-hour application.
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  One hundred and thirty-three eyes of 130 patients undergoing anterior segment intraocular surgery were randomized to either control (64 eyes received topical ofloxacin 1 hour before surgery) or study groups (69 eyes received topical ofloxacin four times a day for 3 days before surgery in addition to 1 hour preoperatively). Eyes in both groups received a periorbital iodine scrub and two drops of topical 5% iodine. Aqueous fluid was obtained at the beginning and conclusion of surgery using a cannula passed through a paracentesis or a needle passed through clear cornea. The aqueous, cannula, and needles were inoculated in blood culture media broth and bacterial growth was identified.
  
  
  RESULTS
  Overall, eight of 89 aqueous samples (9%) obtained using a cannula at the beginning of surgery were culture-positive. Similarly, six of 41 aqueous samples (15%) obtained through a needle through clear cornea at the beginning of surgery showed contamination. At the conclusion of surgery, nine of 112 samples (8%) showed positive cultures. There was no difference in the aqueous contamination rates between the control and study groups.
  
  
  CONCLUSIONS
  Despite the use of a needle to obtain aqueous fluid at the beginning of surgery before creating a paracentesis, the aqueous contamination rate remained higher than that found at the conclusion of surgery. A 3-day application of topical ofloxacin before surgery did not reduce the anterior chamber aqueous contamination rate relative to a 1-hour application.
authors.affiliation: Department of Ophthalmology, School of Medicine, Stanford University, Stanford, California 94304, USA.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Ta
authors.forename: Peter R
authors.initials: PR
authors.lastname: Egbert
authors.forename: Kuldev
authors.initials: K
authors.lastname: Singh
authors.forename: Mark S
authors.initials: MS
authors.lastname: Blumenkranz
authors.forename: Herminia Miño
authors.initials: HM
authors.lastname: de Kaspar
mesh_terms: D000869:Anterior Eye Segment / Q000601:surgery*; D000890:Anti-Infective Agents / Q000008:administration & dosage; D001082:Aqueous Humor / Q000382:microbiology*; D001419:Bacteria / Q000302:isolation & purification; D002404:Catheterization / Q000379:methods; D015818:Eye Infections, Bacterial / Q000382:microbiology* / Q000517:prevention & control; D006801:Humans; D015242:Ofloxacin / Q000008:administration & dosage; D009883:Ophthalmic Solutions; D018918:Phacoemulsification; D011446:Prospective Studies; D013530:Surgical Wound Infection / Q000382:microbiology* / Q000517:prevention & control
chemical_list: D000890:Anti-Infective Agents; D009883:Ophthalmic Solutions; D015242:Ofloxacin