Intravitreal injection of methotrexate in persistent diabetic macular edema: a 6-month follow-up study

To evaluate the efficacy of intravitreal injection of methotrexate (MTX) in patients with persistent diabetic macular edema (DME) nonresponsive to intravitreal bevacizumab.

In this prospective, interventional study, intravitreal injection of 400 μg MTX was performed in eyes with persistent center-involving DME unresponsive to at least three consecutive bevacizumab injections or two consecutive bevacizumab injections plus macular photocoagulation. Best-corrected visual acuity (BCVA), central subfield thickness (CST), and maximum retinal thickness (MRT) were recorded before and 1, 3, and 6 months after injections.

Eighteen eyes of 16 patients with a mean age of 61.1 ± 6.7 years were included. Mean number of intravitreal bevacizumab injections was 3.9 ± 1.8 (range 2-8). The mean change in BCVA was -0.09 ± 0.19, -0.1 ± 0.19, and -0.1 ± 0.19 LogMAR at 1, 3, and 6 months after intravitreal MTX injections, respectively (all P = 0.04). Three eyes (16.6 %) had improvement of at least two lines of BCVA and no eye lost visual acuity. Mean change in CST was -23.7 ± 66.7, -28.7 ± 82.2 and 26.5 ± 83.4 μm at 1, 3, and 6 months after MTX injections, respectively (all P = 0.1). A decrease in CST was found in 13 eyes (72.2 %) at 1 and 3 months, and seven eyes (38.8 %) at 6 months of follow-up. Other eyes showed an increase in CST measurements. Mean change in MRT was -35.1 ± 76.4, -40.6 ± 86.3, and 29.8 ± 68.6 μm at 1, 3, and 6 months after MTX injections, respectively (P = 0.06, P = 0.06, and P = 0.08, respectively). No complication attributable to intravitreal MTX occurred.

In this study, intravitreal injection of MTX resulted in anatomical improvement in a significant proportion of eyes with persistent DME. Significant visual improvement was found in 16.6 % of eyes.