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Subconjunctival anesthesia: an alternative anesthetic method for micropulse cyclophotocoagulation

Poster Details

First Author: D.Wang CANADA

Co Author(s):    A. Arora   S. Nazarali   M. Schlenker   K. Warrian   C. Hanson   P. Gooi     

Abstract Details


Currently retrobulbar anesthesia is used to achieve analgesia in patients prior to micropulse transcleral cyclophotocoagulation (MPCPC), a pulsed cycloablative laser procedure for patients with uncontrolled glaucoma refractory to topical medications who are not ideal surgical candidates. However, retrobulbar anesthesia is associated with the risk of vision-threatening complications including brainstem anesthesia and damage to the optic nerve. We have routinely used subconjunctival anesthesia for MPCPC and believe it to be a suitable and less invasive alternative to retrobulbar anesthesia for adequate pain control prior to MPCPC.


Cloudbreak Eye Care (5340 1 St SW, T2H 0C8), Calgary, Alberta


A retrospective chart review was performed for all consecutive patients that received subconjunctival anesthesia prior to MPCPC at a single center between September 2015 and September 2017. The number of eyes that successfully achieved pain control, treatment duration and treatment area were quantified. Baseline information was collected including demographics (age, gender, eye), glaucoma diagnosis, mean deviation, prior glaucoma procedures, logMAR best corrected visual acuity, IOP, and glaucoma medications. Data analysis was done on SPSS software v23.0. This study adhered to the Declaration of Helsinki and was approved by the Health Research Ethics Board. 


145 eyes in 92 patients were included. 138/145 (95.2%) of eyes successfully underwent subconjunctival anesthesia prior to MPCPC with no complications. Out of the 7 eyes that failed, 1 experienced mild pain, 1 had vasovagal response, 1 had comorbid behavioral disorder, and in 4 patients pain control was inadequate. Laser settings were 2000 mW with treatment durations of 50-500 seconds, and treatment area was either to the superior 180 degrees (12%), inferior 180 degrees (51%), or the entire 360 degrees (37%). Logistic regression found no correlation between baseline characteristics or treatment parameters with success or failure of anesthesia.


Subconjunctival anesthesia is safe and well-tolerated for the majority of patients for pain control for MPCPC procedures, for a wide range of laser treatment durations and areas. More investigation is needed to identify predictors of anesthetic complications. We recommend considering subconjunctival anesthesia as a suitable and less invasive alternative to retrobulbar anesthesia for MPCPC.

Financial Disclosure:

receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented

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