title: What can patients see during glaucoma filtration surgery under peribulbar anesthesia?
abstract: OBJECTIVE
  To describe the visual sensations experienced by patients during glaucoma filtration surgery under peribulbar anesthesia and to determine possible risk factors that may affect the visual sensations experienced.
  
  
  METHODS
  King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.
  
  
  METHODS
  In this prospective questionnaire study, 75 consecutive adult patients listed for glaucoma filtration surgery (trabeculectomy or Ahmed tube implantation) under peribulbar anesthesia were interviewed postoperatively about the visual sensations experienced in their operated eye during the surgery.
  
  
  RESULTS
  The mean age of the 75 patients was 59.7 years (range, 27 to 83, SD +/-12.1). Sixty-five patients (86.7%) perceived light perception during the surgery and the overall light intensity fluctuated in 45 patients (60.0%). The mean age of the patients who retained light perception intraoperatively was significantly lower compared with those who lost light perception (58.3 y vs. 68.8 y; P=0.009). Forty-six patients (61.3%) were able to perceive colors, 32 patients (42.7%) perceived movement, 31 patients (41.3%) saw surgical instruments, and 33 patients (44.0%) reported seeing the surgeon's hands or fingers. The severity of glaucoma did not affect the proportion of patients who perceived the various visual sensations. One patient (1.3%) was frightened by his intraoperative visual experience. Of the remaining patients, 53 (70.7%) said the visual sensations did not affect them, whereas 21 (28.0%) found them unpleasant.
  
  
  CONCLUSIONS
  The majority of patients undergoing glaucoma filtration surgery retained light perception intraoperatively and many also experienced various visual sensations. Only 1.3% of patients were frightened by their visual experience.
authors.affiliation: Department of Anesthesia, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. waleed_riad@yahoo.com
authors.forename: Waleed
authors.initials: W
authors.lastname: Riad
authors.forename: Colin S H
authors.initials: CS
authors.lastname: Tan
authors.forename: Chandra M
authors.initials: CM
authors.lastname: Kumar
authors.forename: Kah-Guan
authors.initials: KG
authors.lastname: Au Eong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local; D005260:Female; D005901:Glaucoma / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D014130:Trabeculectomy; D014788:Vision, Entoptic / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology