Comparing the Effects of Three Different Intravitreal Injection Techniques on Vitreous Reflux and Intraocular Pressure

Purpose: To compare the effects of straight, oblique, and double-plane tunnel scleral intravitreal injection techniques, on short-term intraocular pressure (IOP) changes, occurrence of vitreous reflux (VR), and/or other complications. Methods: A total of 105 patients were included in this prospective study. Patients were assigned randomly to one of the straight injection group (SI; n = 35), oblique injection group (OI; n = 35), or double-plane tunnel injection group (DPTI; n = 35). The occurrence of VR and preinjection and postinjection IOP at 2 and 6 h were compared between groups, and complications were assessed. Results: The mean patient age was 71.1 +/- 6.6 years (range 58 to 86 years; 50 women and 55 men). In the SI, OI, and DPTI groups, VR occurred in 18 (51.4%), 12 (34.3%), and 6 patients (17.1%), respectively. Mean preinjection IOPs were 15.4, 14.8, and 15.6 mmHg, and changed to 17.3, 18.0, and 20.0 mmHg at the second hour, and 15.7, 16.2, and 16.1 mmHg at the sixth hour, respectively. No significant differences among the groups were found in terms of complications such as transient mild uveitis or subconjunctival hemorrhage. Conclusion: Double-plane tunnel injection prevents VR from the injection site and has no additional complications than other techniques.