Differences in pain experience and cooperation between consecutive surgeries in patients undergoing phacoemulsification

The purpose of this study is to compare pain experience and cooperation between consecutive surgeries in patients undergoing phacoemulsification in both eyes, using sub-Tenon's local anesthesia without sedation. In this study, 268 patients with bilateral senile cataracts were recruited. All operations were performed without sedation, using a clear corneal phacoemulsification technique and sub-Tenon's local anesthesia, by one of four surgeons. The first surgery was performed on the eye with the higher grade cataract. The other eye was operated on within 3 months by the same surgeon (mean interval 1.9 +/- 1.1 months). All patients were asked to grade their pain experience during induction and maintenance of anesthesia and also during the phacoemulsification surgery, using a visual analogue scale (VAS) from 0 (no pain) to 10 (unbearable pain) administered after the surgery. The cooperation of the patient was graded from 0 (no event) to 3 (markedeye and head movement and lid squeezing) by the attending surgeon. The VAS scores and cooperation scores of the patients were the outcome measurements. The mean pain score was 2.11 +/- 0.79 in the first eye and 3.33 +/- 0.80 in the second eye during the administration of sub-Tenon's anesthesia, and 1.50 +/- 0.60 in the first eye and 2.10 +/- 0.57 in the second eye during the phacoemulsification surgery. The patient cooperation score was 1.60 +/- 0.75 in the first surgery and 2.08 +/- 0.72 in the second surgery. The differences between the first and second surgeries were statistically significant for all outcome measures (p < 0.01). Patients who previously underwent phaco surgery in one eye experienced more pain and showed worse cooperation during the phaco surgery in the second eye, especially if there was a short time between the surgeries, viz., less than 3 months. Therefore, if the surgeon has difficulty in the first operation gaining the patient's cooperation, the surgeon must be careful: if contralateral eye surgery is required, the addition of sedation/analgesia should be considered or the surgery postponed for a while to abolish the influence of recent memory on the patient's subsequent pain experience.