A Comparative Study Between Single Medial Canthus Injection Using 13 x 0.45 mm Needle and Posterior Sub-Tenon Injection as Local Anesthesia Techniques for Strabismus Surgery in Adults

Norhan A. Sherif1, *, Mayada K. Mohamad1, Ahmed A. Hannon2, Noha A. Osama1
1 Department of Anesthesia, Research Institute of Ophthalmology, Cairo, Egypt
2 Department of Pediatric Ophthalmology and Strabismus, Research Institute of Ophthalmology, Cairo, Egypt

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© 2020 Aly Sherif et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at Department of Anesthesia, Research Institute of Ophthalmology, Cairo, Egypt; Tel: +201223611054;



The quality of ophthalmic anesthesia is an important component of the surgical procedure. There is no absolutely well-tolerated local eye anesthetic technique. However, it is important to choose a technique with high efficacy and safety.


This study aimed to compare the efficacy and safety of peribulbar block using medial canthus single injection and posterior sub-tenon injection techniques.


This prospective observational study was carried out at the Research Institute of Ophthalmology, Cairo, Egypt during the period from March to December 2018. Consecutive 60 patients of both sexes, aged >18 years-old, scheduled for bilateral strabismus surgery were enrolled in this study. In one eye of the sixty patients, medial canthus single injection peribulbar anesthesia was used (Group A), whereas posterior sub-tenon technique was applied in the other eye (Group B).


The median total ocular akinesia score was significantly higher in group A than in group B when assessed at 1, 3, and 5 min (p < 0.001). Each of the intraoperative (at 5 min) and postoperative pain scores showed no significant differences between the two groups (p > 0.05). However, the median scores of surgeon and patient satisfaction were significantly higher in group A compared with group B (3 vs. 2 each, p < 0.05). No patient developed occulocardiac reflex or postoperative nausea and vomiting.


Peribulbar anesthesia by medial canthus single injection showed better akinesia of the globe than sub-tenon injection technique. Otherwise, both techniques were equally effective and safe.

Keywords: Akinesia, Analgesia, Medial canthus, Peribulbar anesthesia, Strabismus, Sub-Tenon.