Intravitreal injections are one of the most commonly performed ocular procedures, but they have often been associated with a host of complications as chronicled in randomized controlled trials. However, a new study in Ophthalmology Retina found that overall, complication rates in routine clinical practice are low compared with clinical trial reporting. As such, the investigators suggest providers should feel confident in the safety and administration of intravitreal injections during times when follow-up office visits and resources may be limited.

The study considered the complications and risk factors related to 44,734 injections performed on 5,318 patients at the Cleveland Clinic Cole Eye Institute from 2012 to 2015. Of the total study subjects, 56% were female, 80% were Caucasian and patients were about 76 years old.

Overall, complications arose in 1.9% of all injections, with 1,031 unique complications in 685 patients (12%). This rate was significantly less than previously reported in clinical trials, which ranged from 62.5% to 90.1%, the study authors noted.

The protocol-driven studies, in the quest to establish safety and efficacy, used pre-determined follow-up schedules in which all adverse events are included, while the current study assessed patient-initiated encounters concerning a complication, which researchers said more closely represents routine clinical practice. Patients may not always report or even notice a transient complication, which could explain the difference between the rates observed in clinical trials and the present study, the investigators explained.

In the current study, the most common minor complications, or those not requiring intervention, were irritation (312) and subconjunctival hemorrhage (284).

The most common serious complications requiring intervention were corneal abrasion (46) and iritis (31). The majority of complications (66%) were adequately managed by a telephone/electronic message encounter.

Of note: no injection protocol parameter—such as type of anesthesia, preparation or post-injection medication—increased the risk of a complication. However, patient sex, age, number of previous injections and provider strongly influenced the risk of patient-reported complications, which providers should take into account to ensure the best possible outcomes, the researchers noted.

Given that most retina providers are still performing intravitreal injections during the COVID-19 pandemic, “knowledge of anticipated complication rates, including those which can be handled with a virtual or telephone encounter, and those of a more serious nature, is helpful for resource planning,” the researchers wrote in their paper.