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A randomized clinical trial of combined topical-intracameral anesthesia in cataract surgery
1Department of Ophthalmology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China.
Objective:
To evaluate the level of patient discomfort during phacoemulsification and implantation of a foldable intraocular lens (IOL) while under topical lidocaine, alone or in combination with intracameral lidocaine.
Design:
A prospective, randomized, controlled trial.
Participants:
Between January and July 1997, a total of 162 patients (162 eyes) scheduled for cataract surgery were randomly assigned to either the placebo group (topical anesthesia with intracameral balanced salt solution [group 1, n = 81]) or the interventional group (combined topical-intracameral anesthesia [group 2, n = 81]).
Interventions:
All patients underwent temporal clear corneal phacoemulsification and implantation of a foldable silicone IOL. All patients received a minimum total of five doses (two drops per dose) of 2% topical lidocaine hydrochloride. Three doses were administered before surgery into the superior and inferior cul-de-sac at 10 minutes, 5 minutes, and immediately before the initial corneal incision. One dose was administered before the commencement of phacoemulsification and another dose before implantation of the IOL. In addition, all patients received an intracameral injection immediately after entrance into the anterior chamber. Patients in group 1 received a 0.5-ml injection of balanced salt solution, and those in group 2 received a 0.5-ml injection of 1% lidocaine.
Main Outcome Measure:
A 10-point visual analogue scale was used immediately after the surgery to assess each patient's overall severity of pain intraoperatively.
Results:
Ninety percent of patients in group 1 and 95% in group 2 assigned a score of 0 or 1 to the level of intraoperative discomfort. The mean pain score +/- 1 standard deviation for group 1 was 0.63 +/- 0.68 and for group 2 was 0.37 +/- 0.58. The difference between the pain scores for the two groups was statistically significant (P = 0.0053). A small but significant proportion (15%) of patients in group 1 expressed distress when the ciliary body was stretched or the iris was manipulated with instruments.
Conclusion:
Although topical lidocaine alone provides adequate anesthesia for phacoemulsification and implantation of a foldable IOL, combined topical and intracameral administration of lidocaine can further minimize intraoperative discomfort.