AUG 20, 2014
Investigators surveyed 530 retina specialists to identify candidate risk factors for the development of sustained IOP elevation that could be further investigated in future studies. The most robust statistical finding was that a high-volume, fast injection technique may lead to persistent IOP elevation.
Physicians who injected greater than 0.05 cc in less than one second were 5.56 times more likely to observe a high frequency of sustained IOP elevation (P = 0.006). Neither injection of high volume nor fast technique alone was predictive of sustained IOP elevation, suggesting these two variables together may have a synergistic effect that results in damage to the trabecular meshwork.
The survey, which included both private and academic practices, was conducted to determine the intravitreal anti-VEGF injection techniques and preferences within the retinal community, and to conduct statistical analysis to generate candidate risk factors for persistent IOP elevation.
Most respondants observed sustained IOP elevation at a frequency of 1% to 5%, much lower than previously published studies reporting a frequency ranging from 3.45% to 11%.
Among other findings, there was no relationship between the frequency of sustained IOP elevation and choice of anti-VEGF treatment. They also found that using a 31-gauge needle was significantly more likely to result in sustained IOP elevation compared to use of other needle gauges including 27, 30 and 32 gauge. The authors hypothesize that decreased reflux with higher gauge needles could possibly account for increased short-term pressure spikes and subsequent injury to the trabecular meshwork, causing sustained IOP elevation. However, they did not detect a significant difference between low gauge (< 31 gauge) and high gauge (≥ 31 gauge) users with respect to sustained IOP elevation.
They conclude that multiple variables are behind the clinical conundrum of sustained IOP elevation, many of which could not be accounted for in this survey design. Further investigation of the relationship between injection techniques and sustained IOP elevation is warranted.