Dexmedetomidine Enhances Onset and Prolongs Peribulbar Block in Eye Surgery: Systematic Review

While peribulbar anesthesia is recognized as a safer alternative to the retrobulbar approach for ocular surgeries, it often suffers from delayed onset and shorter analgesic duration; to address the fragmented evidence from varied earlier trials and resolve this clinical gap, Dr. V. Kavitha and colleagues from the Department of Pediatric Ophthalmology at Sankara Eye Hospital aimed to formally evaluate the clinical efficacy and safety of dexmedetomidine as an adjuvant.

Therefore, the systematic review of 22 randomized controlled trials evaluated dexmedetomidine against normal saline or other adjuvants in adults undergoing cataract and vitreoretinal surgeries. Primary clinical endpoints focused on the onset and duration of sensory and motor ocular blocks (globe and lid anesthesia and akinesia). Secondary outcomes assessed intraocular pressure, postoperative analgesic needs, and perioperative complications.

Key Clinical Findings of the Review Includes:

• Accelerated Block Onset: Reviewers noted that across eighteen trials, dexmedetomidine consistently demonstrated a statistically significant reduction in the time required to achieve the onset of globe anesthesia, globe akinesia, and lid akinesia when compared to normal saline.

• Prolonged Analgesic Duration: Investigators found that the adjuvant effectively extended the duration of anesthesia and akinesia in the globe and lid in comparison to normal saline and clonidine, reducing the frequent need for block supplementation.

• Favorable Ocular Hemodynamics: Analysts observed that the administration of this selective alpha-2 adrenoreceptor agonist reliably lowered intraocular pressure and reduced the need for early postoperative rescue analgesia without inducing severe intraoperative or postoperative complications.

• Dose-Dependent Efficacy: Scientists determined through multiple comparative analyses that progressively increasing the dexmedetomidine dosage from 15 micrograms up to 50 micrograms yielded faster block onsets and lengthier overall durations.

The results suggest that dexmedetomidine serves as a highly efficacious adjuvant in peribulbar anesthesia, significantly optimizing surgical conditions by hastening the onset and extending the duration of both sensory and motor ocular blocks.

Thus, the review concludes for clinicians performing ophthalmic procedures, incorporating this specific agent into the local anesthetic mixture may act as a beneficial strategy to safely enhance patient comfort and provide stable intraoperative operating conditions.

Although constrained by the regional concentration of the included trials and considerable methodological heterogeneity regarding drug dosing without clear sample size determinations, these promising findings naturally encourage the execution of large-scale, culturally diverse randomized controlled trials to further substantiate its routine clinical application.

Reference

Kavitha V, Seetharamiah S, Heralgi MM. Efficacy and safety of dexmedetomidine as an adjuvant in peribulbar anesthesia: A systematic review. Delhi J Ophthalmol 2026;36:87-96.