Earlier neurolept anesthesia for laser-assisted cataract surgery: Timing may not be everything

Lynda Charters

A recent study may indicate the need for future research to assess the relationship between pain and the anterior chamber depth.

This article is reviewed by Rishi Gupta, BSc.

The timing of administration of neurolept anesthesia for refractive laser-assisted cataract surgery does not seem to affect patients’ perception of pain. A recent study showed no difference in the pain scores between early and standard administration of anesthesia on postoperative day 0 (POD0) and postoperative week 1 (POW1), noted Rishi Gupta, BSc, lead study author from the University of Ottawa Faculty of Medicine, Ottawa, Canada.

Refractive laser-assisted cataract surgery is a 2-phase event, i.e., application of femtosecond laser that is followed up by the manual surgery. The authors theorized that the timing of the administration of the anesthesia may affect the patients’ perception of pain, explained Sohel Somani, MD, senior author of the study.

Study design/findings

This study was a prospective, randomized controlled trial that included 38 patients who received anesthesia at the standard time, defined as after completion of the refractive laser-assisted cataract surgery and immediately before the draping of the eye, and 35 patients who received early administration of anesthesia, defined as before the start of the laser-assisted cataract surgery.

The primary outcome was the pain scores using the Visual Analog Scale on POD0 and POW1. The secondary outcomes were the baseline ocular data, surgical parameters, anesthesia doses, vital signs, and anxiety scores.

The investigators found that the preoperative heart rate, intraoperative mean arterial pressure, and postoperative heart rates differed significantly between the two cohorts, with significantly higher rates seen at all time points (p=0.02, p=0.04, and p=0.04, respectively) in the early administration group. Interestingly, no differences in pain scores between the 2 patient cohorts were seen at the 2 postoperative time points.

However, and even more interestingly, the anterior chamber depth was a highly significant factor in this study. The data showed when considering all patients, each 1-mm increase in the anterior chamber depth caused an increase of 1.51 pain units (p=0.007) at the evaluation on POW1. Regarding the pain scores at that same time point in all patients, the second eye had an increase of 0.71 pain unit (p=0.02) compared with the first eye.

“Anterior chamber depth was correlated strongly with the pain perceived at the POW1 evaluation, which indicates the need for future research to assess the relationship between pain and the anterior chamber depth,” the authors commented.

They also advised that increasing the dose of midazolam can be administered to alleviate the patients’ pain associated with the increased anterior chamber depth.

Rishi Gupta, BSc
E: rgupt010@uottawa.ca
Sohel Somani, MD
E: sohel@uptowneye.ca
This article was adapted from Gupta’s presentation at the Association for Research in Vision and Ophthalmology 2021 virtual annual meeting. He has no financial interest in this subject matter.