Local anesthesia by peribulbar block for cataract extraction in an eye relief camp. A double-masked, randomized controlled trial

Abstract

Objective: To test the hypothesis that the median scores for globe anesthesia are not significantly different for patients receiving local anesthesia (LA) by peribulbar block (PB) than for those receiving retrobulbar block (RB) for cataract surgery.

Design: Double-masked, randomized controlled trial.

Setting: An eye camp in Bhetwa, India, base hospital was King George's Medical College, Lucknow. (Eye camps are temporary set-ups used for cataract surgery throughout rural India.) Study carried out over a 2-day period.

Patients: Out of 125 patients eligible for intracapsular cataract extract on under LA, 122 agreed to enter the trial, and were randomly allocated to 2 groups just before the operation. The groups were equal in size and similar in composition in terms of patient age and sex.

Intervention: PB or RB infiltrated with 5 mL of the same anesthetic at the same site but with a different needle size and direction.

Main outcome measures: Globe anesthesia (primary outcome), globe akinesia, lid akinesia, pupillary dilatation, and hypotony were scored separately on a 4-point scale during surgery by a masked surgeon. During infiltration, surgery, and the 1st 30 minutes after surgery, pain was scored by patients and recorded by an interviewer.

Results: Median scores for globe anesthesia were 4.0 in both groups, and the Mann-Whitney test revealed no difference in the medians of these scores (P = 0.6). There was no difference in scores on other outcomes measured, except lid akinesia, which was better with PB. Subjective pain scores were significantly higher with RB. The surgeon's guess about the type of LA administered was correct only for 58% of patients.

Conclusion: PB is no different from RB in terms of producing globe anesthesia when used for cataract surgery at eye camps.