A short-term elevation in IOP has been shown to be a side effect of anti-VEGF treatment, but some studies have suggested elevated IOP, along with a rise in ocular hypertension (OHT), may also occur in patients who receive this therapy through silicone-free syringes. Researchers recently aimed to pinpoint the difference in incidence of OHT following the introduction of filtered anti-VEGF in silicone-free syringes.
A retrospective review of patients receiving intravitreal anti-VEGF injections was performed. There were two groups—100 patients who received nonfiltered anti-VEGF insulin syringes (IS group) and another 100 who received filtered anti-VEGF in silicone-free syringes (SFS group). Follow-up data was collected one year later, and the primary outcome was the cumulative incidence of IOPs of 21mm Hg and 30mm Hg.
In the IS group, 34% of participants had an IOP of 21mm Hg, and 15% achieved the same outcome in the SFS group. On the other hand, an IOP of 30mm Hg was documented in 8% of the IS group and 0% of the SFS group. The incidence of IOP-lowering therapy was 13% in the IS group and 0% in the SFS group.
The study concluded that the incidence of OHT and IOP-lowering treatments related to anti-VEGF injections decreased following the introduction of filtered anti-VEGF in silicone-free syringes.
Storage and compounding methods of anti-VEGF medications may contribute to clinically significant long-term increases in IOP, as the authors mentioned a number of studies have produced differing and even contradictory results when it comes to the safety of transferring anti-VEGF medication from a glass vial of a larger volume to a syringe of a smaller volume for storage purposes.
“We hypothesized that unfiltered anti-VEGF medication carries particles that overwhelm the phagocytosis pathway in the trabecular meshwork, causing damage and OHT in susceptible patients,” the authors explained in their study. They noted that this same mechanism may lead not only to OHT, but also to glaucoma in pigment dispersion syndrome and pseudoexfoliation.
Bae SS, Koenigstein D, Weaver T, et al. Incidence of ocular hypertension after anti-VEGF infections: examining the effect of drug filtration and silicone-free syringes. Can J Ophthalmol. [Epub ahead of print].