title: Effect of fentanyl versus buprenorphine on the pupil size in phacoemulsification cataract surgery.
abstract: BACKGROUND
  Despite several recent innovations in phacoemulsification surgery, importance of pupil diameter in this surgery is becoming more evident.
  
  
  OBJECTIVE
  To compare the effect of opioid agonist (fentanyl) versus opioid agonist-antagonist (buprenorphine) on pupil diameter in cataract surgery and to choose the best opioid in high-risk phacoemulsification surgery.
  
  
  METHODS
  In this randomized double-blinded clinical trial, 60 patients who were candidates for elective phacoemulsification surgery were randomly divided into two equal groups: experimental (buprenorphine, 0.3 μg/kg) and control (fentanyl, 1 μg/kg). Pupil diameter was measured preinjection and at several times postinjection. Blood pressure was recorded at several intervals, as well as shivering, nausea and vomiting, and recovery time.
  
  
  RESULTS
  Mean (SD) recovery time was significantly less in the control group (19.46±5.43) than in the experimental group (33.23±10.75) (P<0.0001). The constriction effect (ie, pupillary diameter in mm) was significantly lower in the experimental group (0.53±0.45) than in the control group (1.06±0.52) (P=0.0001). The percentages of constriction effect in experimentaland control groups were 7.68% and 15.07%, respectively. The eye was two times more constricted in the control group in comparison with the experimental group after induction of anesthesia.
  
  
  CONCLUSIONS
  Buprenorphine is a better solution to decrease pupil constriction in comparison with fentanylinhigh-risk phacoemulsification surgery.
authors.affiliation: Department of Anesthesiology, Bushehr University of Medical Sciences, Bushehr, Iran.
authors.forename: Abdolreza Najafi
authors.initials: AN
authors.lastname: Anaraki
authors.forename: Abbas
authors.initials: A
authors.lastname: Akrami
authors.forename: Niloofar
authors.initials: N
authors.lastname: Motamed
authors.forename: Elham
authors.initials: E
authors.lastname: Seydali