To investigate the outcome of intravitreal bevacizumab (IVB) combined with posterior subtenon triamcinolone acetonide injections compared to IVB injection alone in patients with diabetic macular edema (DME).

IVB injection (IVB group) and combination therapy injection (combination group) were administered to 35 eyes and 31 eyes, respectively, diagnosed with proliferative diabetic retinopathy combined with DME. Changes in best corrected visual acuity (BCVA), central macular thickness (CMT), total macular volume (TMV), amount of hard exudates and intraocular pressure (IOP) were compared retrospectively between groups prior to injection and 1, 2 and 3 months after injection.

BCVA changes in both groups were only statistically significant at 4 weeks after injection. Reduction of CMT and TMV was maintained for 1 month after treatment in all groups, but CMT and TMV deteriorated 2 months after treatment. No significant differences in BCVA, CMT or TMV were detected between the IVB and combination groups. The amount of hard exudates were only significantly decreased at month 3 in the combination group whereas the amount of hard exudates was not significantly different at 3 months in the IVB group (at baseline 2,899 ± 2,314 pixels vs. at 3 months 2,536 ± 1,981 pixels, p -value = 0.041). IOP showed no significant difference between the groups. Elevated IOP or endophthalmitis were not observed.

In terms of BCVA improvement, subtenon triamcinolone provided no additional benefit on CMT and TMV reduction. However, combination therapy was effective in reducing the amount of hard exudates at 3 months.