Efficacy of intravitreal injection of the dexamethasone intravitreal implant Ozurdex® in treatment of patients with refractory diabetic macular edema of different optical coherence tomography patterns

Objective To investigate the efficacy of intravitreal injection of Ozurdex® in the treatment of refractory diabetic macular edema (DME) with different optical coherence tomography (OCT) patterns. Methods A total of 38 patients (41 eyes) who underwent fundus examination and were diagnosed with refractory DME in Department of Ophthalmology in our hospital from June 2018 to June 2020 were enrolled in this study, and according to the OCT pattern, they were divided into diffuse retinal thickening (DRT) group, cystoid macular edema (CME) group, and serous retinal detachment (SRD) group. Intravitreal injection of Ozurdex® was performed for all diseased eyes as needed, and best corrected visual acuity (BCVA) and OCT measurements were performed before treatment and at 1, 3, and 6 months after treatment. The three groups were compared in terms of BCVA, central foveal thickness (CFT), the integrity of external limiting membrane, ellipsoid zone integrity, and the number of hyperreflective dots (HRDs) before and after treatment. Results All three groups had a significant improvement in BCVA at 1, 3, and 6 months after treatment (Fintra-group=15.334-42.187,P<0.05), and the DRT and CME groups had a significant reduction in CFT from 1 month to 3 months after treatment (Fintra-group=4.009,7.946,P<0.05), while for all three groups, CFT at 3 months after treatment was significantly lower than that at 6 months after treatment (Fintra-group=5.591-12.498,P<0.05). At 1, 3, and 6 months after treatment, there were significant differences in △BCVA and △CFT between the three groups (Finter-group=7.020-20.553,P<0.05), and the SRD group showed the greatest improvement, followed by the CME group and the DRT group. There was no significant difference in the proportion of diseased eyes with different numbers of HRDs between the three groups at each time point (P >0.05), and at 1, 3, and 6 months after treatment, there was a significant change in the proportion of diseased eyes with different numbers of HRDs (H=23.645-39.117,P<0.001). At 6 months after treatment, there was a significant increase in the number of diseased eyes with complete ELM and ellipsoid zone between all diseased eyes (χ2=15.814,8.264,P<0.05). Conclusion Ozurdex® can persistently alleviate macular edema in patients with refractory DME of different OCT patterns, significantly improve their visual function, and reduce inflammatory substances, with the most significant improvement in SRD patients.