Major factors affecting intraocular pressure spike after intravitreal ranibizumab injection: Vitreous reflux and its amount

Abstract

Purpose:The aim of this study was to assess the effect of vitreous reflux and its amount on short-term intraocular pressure after intravitreal injection of ranibizumab.Methods:The study included 316 eyes of 276 patients. Intraocular pressures were measured before intravitreal injection (preIOP), immediately after intravitreal injection (postIOP0), and 30 min after intravitreal injection (postIOP30). The amount of vitreous reflux was evaluated by measuring conjunctival bleb diameter, and patients were grouped as; group 1: no vitreous reflux, group 2: less vitreous reflux, and group 3: more vitreous reflux. The data were analyzed using variance analysis, chi-square test, and regression analysis.Results:PostIOP0 values were highest in group 1, followed by group 2 and group 3 (all p values < 0.001). PostIOP30 values were similar in group 1 and group 2 (p = 0.261), but were lower in group 3 than other two groups (p < 0.001, p = 0.001, respectively). Vitreous reflux was identified as the only factor affecting postinjection intraocular pressure changes (p < 0.001), and a negative correlation was found between the total number of intravitreal injection and vitreous reflux (p = 0.032).Conclusion:The major factor affecting short-term postinjection intraocular pressure elevation was vitreous reflux, and intraocular pressure levels increased as the amount of vitreous reflux decreased. Vitreous reflux and its amount decreased as the total number of intravitreal injection increased.

<p>Vitreous Reflux Frequency and Intraocular Pressure After First-Time Intravitreal Aflibercept Injections: Comparison of 30- and 32-Gauge Needles</p>

“…Uyar et al hypothesized that recurrent injections in the same quadrant may decrease the total amount of VR because of recurrent scleral trauma. 4 We hypothesized that recurrent injections would cause several VR events and consequently reduce the liquefied vitreous body. First-time intravitreal injection patients have a sufficient liquefied vitreous body, so VR occurs easily.…”

“…We guessed the difference in the total amount of injected aflibercept to be a reason for this finding. Because the inner diameter of a 32-gauge needle is small and aflibercept is sticky, the amount of aflibercept that attached to the inner wall of the needle might be larger than that in the 30- 4 we only measured the VR rate. In the near future, we will try to determine why immediate postinjection IOP was higher when 30-gauge needles were used than when using 32gauge needles were used.…”

“…IOP is affected by many factors, but VR is the most important determinant of IOP elevation after intravitreal injection. 2,[4][5][6][7] Some authors have concerns that a momentary IOP elevation may further damage the ganglion cells in the optic nerve, especially in patients who suffer from glaucoma or optic nerve damage. 7 Pang et al reported that IOP immediately after intravitreal injection was significantly higher when a 32-gauge needle was used as opposed to when a 30-gauge needle was used (41.4 vs 30.8 mmHg, respectively).…”

“…Uyar et al reported that VR and its amount decreased with increasing total number of intravitreal injections. 4 To the best of our knowledge, there are no reports about VR associated with first-time intravitreal injection of aflibercept (Eylea ® ; Regeneron, Tarrytown, NY, USA) only. The aim of this study is to investigate how VR rates differ when 30-and 32-gauge needles are used to administer first-time intravitreal aflibercept injections.…”

“…and Uyar et al4 reported that lens status was not correlated with VR. No significant correlation was observed between VR and axial length or between VR and lens status when using either a 30-gauge or 32-gauge needle.…”