Effect of needle size on pain degree and intraocular pressure after intravitreal injection: a randomized observational study

Abstract

BACKGROUND:Intravitreal injection (IVI) is a common vitreoretinal procedure, and in most patients, multiple IVIs related to the course of their disease have to be performed. Pain sensations during IVI can reduce the desire to continue repeated IVI and can cause complications due to sudden eye movements. The purpose of this study was to compare the effect of needle size on immediate intraocular pressure (IOP), vitreous reflux, and pain experienced in patients after the IVI procedure. MATERIAL AND METHODS: One hundred and ten eyes of 110 patients who were first administered intravitreal ranibizumab or aflibercept were randomized according to the needle size, 30-gauge (Group 1) or 26-gauge (Group 2). The reflux was graded per the IVI procedure. Immediately after IVI, patients were asked to assess the degree of pain with a visual analogue scale (VAS). The IOP measurements were performed 30 minutes after the operation. The average of VAS scores was used as the primary outcome. RESULTS: Both groups consisted of 55 eyes. The mean VAS score was 2.18 ± 1.82 in Group 1 and 4.00 ± 2.36 in Group 2. The mean vitreous reflux was lower in Group 1 than in Group 2. The mean IOP was comparable between the groups (26.3 ± 5.66 / 25.4 ± 4.02 mm Hg). The groups were divided into subgroups according to intravitreal agent use; no statistical difference was observed in VAS scores. CONCLUSIONS: The 30-gauge needle was more comfortable and safer than the 26-gauge needle for the IVI procedure.