Can Needle Bevel Tip Orientation Influence Pain Perception Associated with Intravitreal Injection?

Abstract

Introduction: Reduction of pain perception associated with intravitreal injections is crucial factor for improving compliance of the patient to the planned subsequent injections. Aim: This study aimed to evaluate relation of pain perception with initial needle bevel tip orientation during intravitreal injection. Materials and Methods: A prospective interventional study conducted on 120 eyes of 120 patients at the single tertiary care centre between December 2017 to January 2020 , who never underwent any intravitreal injection and were planned for their first intravitreal injection of ranibizumab in either of their clinically indicated eye for conditions such as Neo-vascular Age Related Macular Degeneration (ARMD), central Diabetic Macular Oedema (DME) and macular oedema secondary to Retinal Vein Occlusion (RVO). Fifty per cent (50%) of the patients received intravitreal injection with needle bevel tip oriented parallel to limbus margin and fifty per cent (50%) of patient received intravitreal injection with needle bevel tip oriented perpendicular to the limbus margin. The primary outcome was to compare the level of pain perception of the subject patients by using Visual Analogue Scale (VAS) in the immediate postprocedure period. Data collected in MS excel and analysed by using SPSS Version 24.0. Independent t-test was used for the comparison of the two groups. Chi-square test was used for the comparison of nominal variables of subject groups. Pearson’s correlation test was used to evaluate the relationship between quantitative variables and pain scores. The p-values smaller than (<0.05) were considered as statistically significant. Results: Pain perception scores assessed on the VAS (0-100mm) ranged from 0.8 to 39, with a mean of 18.13±7.65. Significant correlation was found with two different mode of orientation of needle bevel tip. Patients perceived less pain with needle bevel tip oriented perpendicular to the limbus margin compared to parallel to limbus margin (p=0.0001). Conclusion: Pain perception associated with intravitreal injection can be further minimised by orientating the bevel needle tip as perpendicular to limbus margin while initiating the insertion of injection into the indicated eye.