Introduction Patient-reported pain during intravitreal injection (IVI) may vary by injection quadrant and influence adherence to repeated treatments. Hence, this study aimed to quantify whether patient-reported pain differs by IVI quadrant and identify the least-painful approach. Methods We searched 13 literature databases on 15 October 2025 for clinical studies reporting patient-reported IVI pain stratified by injection quadrant (superotemporal ST, superonasal SN, inferotemporal IT, inferonasal IN). Random-effects meta-analyses synthesized mean differences (MD) in 0-10 visual analogue scale (VAS) pain across all six pairwise quadrant contrasts. All eligible studies were included for a qualitative review and a meta-analysis. The review was prospectively registered (PROSPERO CRD420251164189). Results Seven studies comprising 2048 IVI were included (ST 611, SN 469, IT 556, IN 412). Most injections involved anti-VEGF agents. All injections were performed under topical anesthesia (100%; drops or gel), with no subconjunctival anesthesia reported (0%), and pain was recorded immediately post-procedure using VAS-derived scales. Across all six pairwise contrasts, pooled mean differences between quadrants were small (typically 80%). Conclusions Current evidence does not demonstrate a clearly less painful quadrant for intravitreal injections. Estimates varied across studies and heterogeneity was substantial, limiting confidence in any single average quadrant effect. Efforts to minimize IVI-related pain should prioritize optimized anesthesia protocols, communication, and injection technique, while future studies should standardize pain measurement and quadrant allocation to clarify whether subtle quadrant effects exist. Trial Registration PROSPERO registration: CRD420251164189.
Sabaner et al. (Thu,) studied this question.