Drug reflux during posterior subtenon infusion of triamcinolone acetonide in diffuse diabetic macular edema not only brings insufficient reduction but also causes elevation of intraocular pressure.

Background: At the time of posterior subtenon infusion of triamcinolone acetonide (STI-TA) in patients with diabetic macular edema (DME), drug reflux of TA has sometimes been observed from the conjunctival incision site. We investigated the influence of this reflux on regression of DME and postoperative intraocular pressure (IOP).
Methods: STI-TA was performed on one hundred and twenty-four eyes of 88 consecutive patients with DME. Eligible eyes were divided into two groups: those with observed drug reflux of TA and those without observed drug reflux of TA. Visual acuity (VA), foveal thickness (FT) and IOP were monitored in each eye for up to 12 weeks after STI-TA.
Results: STI-TA with drug reflux was observed in ten individual eyes of seven patients. These patients were significantly younger than those patients without observed drug reflux. After STI-TA, both improvement of VA and regression of FT in reflux(+) eyes were less than in reflux(-) eyes. Postoperative IOP elevation in reflux(+) eyes was much higher, and four of the ten eyes needed anti-glaucoma therapy. This was in contrast to three of the 118 eyes without drug reflux that required anti-glaucoma therapy.
Conclusions: At the time of STI-TA in DME, drug reflux of TA is a risk factor not only for insufficient reduction of edema, but also for postoperative IOP elevation.