Handheld Vibrator Versus Topical Eye Drops as Anesthesia for Intravitreal Injections

Overview

Intravitreal injections are an efficient method of delivering therapeutic levels of medications to the posterior segment of the eye. Prior to receiving an injection, there are various methods to provide ocular anesthesia. Vibration may have an anti-nociceptive effect by directly decreasing the sensitivity of peripheral nociceptors or by reducing signal transmission from peripheral nociceptors to the brain with activation of vibratory sensation pathways. The purpose of this study is to evaluate the use of a handheld fingertip vibrator compared to topical eye drops for pain control while performing intravitreal eye injections. A secondary objective of the study is to measure corneal and conjunctiva sensitivity with and without activation of the vibrator to the lower lid using a Luneau Cochet-Bonnet aesthesiometer.

A total of 80 patients will be recruited for part 1 of the study. Participants will be randomized in a 1:1 ratio to a standard anesthetic group or standard anesthetic with vibration groups. All intravitreal drugs will be delivered via 30 gauge needles through the pars plana in the inferotemporal quadrant 3.5 to 4 mm posterior to the limbus. Once recruited, a single eye requiring injection for each enrolled patient will be randomized into 1 of 2 groups: aesthesiometer measurement alone with sham vibration (vibrator will not be triggered) (Group 1) or handheld vibrator application and triggering followed by aesthesiometer measurement (Group 2). The vibrator will be applied to the lower eyelid while retracting it during standard intravitreal injection prepped with topical anesthetic (Proparacaine 1%) and Betadine. The main outcome measure of will be patient comfort, as measured by the patient using a standardized Wong-Baker FACES Pain Rating Scale. An additional 30 eyes of 30 healthy patients not requiring intravitreal injection will be recruited to determine the effect of vibrator application and triggering to the lower lid on corneal and conjunctival (inferotemporal quadrant) sensation as measured using an aesthesiometer. No topical anesthetic will be applied prior to esthesiometry measurements are taken with and without vibration triggering. All patient identifying information will be removed and patients will be identified with a random number. Data will be checked regularly by a data monitoring committee. Patient records will be reviewed and the following data will be collected: demographic data (age, gender, injected eye, reason for injection), best-corrected visual acuity, intraocular pressure, and complications/adverse events associated with intravitreal injections. Statistical analyses will include univariate comparisons between treatment groups using the Student t-test for continuous variables and χ2 test or Fisher's exact test for categorical variables.