title: Response of intraocular pressure to retrobulbar and peribulbar anesthesia.
abstract: OBJECTIVE
  To evaluate the response of intraocular pressure (IOP) to retrobulbar and peribulbar anesthesia.
  
  
  METHODS
  Patients were prospectively masked and randomized to receive either 4 cc of retrobulbar anesthesia (X = 29) or 6 cc of peribulbar anesthesia (X = 30), each consisting of a 50:50 mixture of 2% xylocaine and 0.75% bupivacaine with 150 units of hyaluronidase. IOPs were measured pre-anesthesia and 1, 2, and 5 minutes post-anesthesia in nonglaucoma patients undergoing cataract extraction and intraocular lens implantation.
  
  
  RESULTS
  Mean IOPs in the retrobulbar group as determined with a tonometer were 18.24, 18.66, 19.14, and 17.86 mm Hg pre-anesthesia and 1, 2, and 5 minutes post-anesthesia, respectively. In the peribulbar group, the mean IOPs were 18.53, 21.20, 20.40, and 19.20 mm Hg, respectively. The 1-minute pressures in the two groups were statistically different (P = .023). Within the peribulbar group, the 1- and 2-minute pressures were statistically different from the pre-anesthesia IOP (P = .001 and P = .018, respectively).
  
  
  CONCLUSIONS
  Peribulbar anesthesia, with its higher volume of anesthetic (6 vs 4 cc), results in a higher initial IOP. This difference was slight and short lived, and occurred in the absence of any external ocular compression. This study may have application in avoiding elevation of IOP in select patients undergoing a local procedure.
authors.affiliation: Ophthalmology Service, Walter Reed Army Medical Center, Washington, DC, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Sanford
authors.forename: O E
authors.initials: OE
authors.lastname: Minoso y de Cal
authors.forename: D A
authors.initials: DA
authors.lastname: Belyea
mesh_terms: D000368:Aged; D000772:Anesthesia, Local / Q000379:methods*; D002045:Bupivacaine; D002387:Cataract Extraction; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008012:Lidocaine; D008297:Male
chemical_list: D008012:Lidocaine; D002045:Bupivacaine