Effect of Needle Gauge Size on Pain During Intravitreal Anti-VEGF Injection: A Systematic Review and Network Meta-Analysis

INTRODUCTION: Concerns related to pain from intravitreal injections are one of the key factors mentioned by patients when asked about therapy. In this systematic review and network meta-analysis, we evaluate the literature of comparative clinical trials on the relationship between needle gauge size and pain experience during intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy.

METHODS: We searched 12 literature databases on 14 October 2023 for comparative studies of gauge sizes for intravitreal anti-VEGF injections. The primary outcome of interest was the reported pain experience immediately after the injection. All outcomes of pain were transformed into standardized effect sizes using Cohen's d. Using a network meta-analysis approach, we were able to compare all gauge sizes and rank them according to the reported pain experience.

RESULTS: We identified nine eligible studies with data on a total of 998 patients and 1004 eyes. Needle sizes studied were 26-gauge, 27-gauge, 29-gauge, 30-gauge, 32-gauge, 33-gauge, and 34-gauge. A complete network was present, which allowed for a network meta-analysis. We used the thickest (26-gauge) needle as the reference group and observed a clear trend of lower pain experience with thinner gauge sizes (d: -0.4, d: -2.7, d: -3.8, d: -4.8, d: -4.5, and d: -5.3; respectively, for 27-gauge, 29-gauge, 30-gauge, 32-gauge, 33-gauge, and 34-gauge).

CONCLUSION: A gauge size of 30 or thinner may minimize patient discomfort related to intravitreal anti-VEGF therapy.