Pain caused by intravitreal injection may be lessened through topical anesthesia

Retina. 2011;31(3):535-539.

Topical anesthesia may limit pain caused by intravitreal injections, a study found.

The prospective masked study used a randomized block design. Twenty-four patients were intravitreally injected four times in combination with four different types of anesthesia: topical proparacaine, topical tetracaine, lidocaine pledget and a subconjunctival injection of lidocaine. To prevent bias, the order of injections was different for each patient.

All patients received at least one intravitreal injection before the study, with a mean of 12.9 previous injections.

Immediately after injection, patients were asked to grade their pain on a 0 to 10 scale for the injection as well as the anesthesia. The average combined pain scores for injection and anesthesia were 3.5 for proparacaine, 4.1 for tetracaine, 4.4 for lidocaine pledget and 3.8 for subconjunctival lidocaine.

Differences in pain grade were not statistically significant; neither were the individual injection or anesthesia pain scores.

Fifty-four percent of eyes that received subconjunctival lidocaine experienced subconjunctival hemorrhage. However, none of the other anesthesia methods was associated with this complication or any other complication.

The study authors suggested that future analyses assess pain experienced after the immediate post-injection period.