Measurement of Acute Intraocular Pressure Elevation Immediately After Intravitreal Anti-VEGF Injection and Analysis...

To compare and evaluate, across different agents, the risk of intraocular pressure (IOP) elevation after anti-VEGF therapy and the accuracy of prefilled syringes.

Total of 175 eyes treated with anti-VEGF drugs were enrolled for this study. An accuracy evaluation of the prefilled syringes was conducted involving 25 participants, comprising 17 physicians and 8 nurses. The anti-VEGF agents including aflibercept 2 mg, aflibercept 8 mg, brolucizumab, faricimab, and ranibizumab-BS were assessed. IOP was measured before, and at 1 and 15 minutes after intravitreal injection, and analyzed separately for each drug. Furthermore, prefilled syringes of aflibercept 2 mg, brolucizumab, and ranibizumab-BS, as well as 1-mL syringes filled with saline solution, were equipped with 30-gauge needles, followed by careful removal of air. The weight of the saline discharged according to the scale marking was measured using an electronic balance.

At 1 min after intravitreal injection, the IOP was highest in the aflibercept 2 mg group, with a mean value of 52.8 mmHg. A mild inverse correlation was observed between axial length and IOP elevation at 1 min post-injection, suggesting that eyes with longer axial length exhibited less pronounced IOP increases. In the syringe accuracy analysis, the prefilled syringe of aflibercept 2 mg expelled a significantly larger volume, with a mean of approximately 0.076 mL, compared to other prefilled syringes.

Intravitreal injection using the aflibercept 2 mg prefilled syringe may deliver approximately 1.5 times the intended volume into the eye. This may raise safety concerns, such as the risk of transient vision loss due to marked immediate IOP elevation, and may also affect clinical outcomes and the validity of clinical trials.