Long-term efficacy and duration of action of dexamethasone implant, in vitrectomised and non-vitrectomised eyes with persistent diabetic macular oedema

Abstract

Purpose: To evaluate the efficacy and duration of action of an intravitreal (dexamethasone (Ozurdex)) implant in vitrectomised and non-vitrectomised eyes with persistent diabetic macular oedema (DMO).

Methods: We retrospectively analysed the records for 18 eyes that had or had not been vitrectomised but required an intravitreal dexamethasone implant for DMO after a poor response to anti-vascular endothelial growth factor. Optical coherence tomography and visual acuity (VA) examinations were performed before and 1, 3 and 6 months after implantation. The six months following implantation constituted one treatment round; up to three rounds were studied.

Results: Ten of 18 eyes had undergone vitrectomy. Best-corrected visual acuity (BCVA) and central macular thickness (CMT) were significantly improved by months 1-3 after implantation of the Ozurdex device in all rounds of treatment. The BCVA and CMT deteriorated gradually after month 3 through to month 6 post implantation. There were no statistically significant differences between the vitrectomised and non-vitrectomised groups at any time point. When the implantation interval was <6 weeks from the end of each treatment round, the improvement in BCVA and CMT was obvious even after 18 months of treatment.

Conclusions: Vitrectomy did not have a negative effect on the duration of action or efficacy of the Ozurdex implant in patients with persistent DMO. The implant started working from the first month after implantation regardless of whether vitrectomy had or had not been performed. The maximum functional and anatomic improvement was achieved in the first 3 months post implantation in all treatment rounds.

Fig. 1

Changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) during three rounds of treatment (lasting 18 months) in vitrectomised and non-vitrectomised groups. a Graph showing the changes in BCVA from baseline until the end of 18 months of follow-up. b Graph showing the changes in CMT (μm) from baseline until the end of 18 months of follow-up. The baseline, second implant and third implant entries represent the starting points of three different rounds of treatment (first to third implants). The red lines indicate the vitrectomized group. The blue lines indicate the non-vitrectomized group. The data are shown as the mean. The error bars show the standard deviation

Fig. 2

Mean best-corrected visual acuity (BCVA) and central macular thickness (CMT) in vitrectomised and non-vitrectomised groups during three rounds of treatment. a Differences in BCVA during round 1 of treatment in both groups. b Differences in BCVA during round 2 of treatment in both groups. c Differences in BCVA during round 3 of treatment in both groups. d–f Quantification of mean CMT during rounds 1, 2 and 3 of treatment. The data are shown as the mean. The error bars show the standard deviation. Significant difference from baseline, second implant and third implant time points presented with *p < 0.05, **p < 0.01, ***p < 0.001, ns no statistically significant difference