Efficacy of intravitreal injection of ranibizumab for different patterns of optical coherence tomography of diabetic macular edema and the relationship between integrity of ellipsoidal zone and visual acuity outcomes

Abstract

Objective To observe the efficacy of intravitreal injection of ranibizumab (IVR) for different patterns of optical coherence tomography (OCT) of diabetic macular edema and the relationship between integrity of ellipsoidal zone and visual acuity outcomes. Methods Eighty-five IVR treated eyes were enrolled. The examination of BCVA was according to Early Treatment Diabetic Retinopathy Study, and the results were recorded as logarithm of the minimum angle of resolution (logMAR). Frequency-domain OCT was used to measure the central foveal thickness (CFT) and the integrity of ellipsoidal zone. All eyes were classified as diffuse macular edema (DRT group, 31 eyes), cystoid macular edema (CME group, 29 eyes), and serous retinal detachment (SRD group, 25 eyes). All the patients were treated with intravitreal injection of 0.05 ml (0.5 mg) ranibizumab. The mean follow-up time was (9.21+3.56) months after IVR treatment. The changes of BCVA and CFT in 3 groups were compared and analyzed after 3, 6 and 12 months. According to visual acuity at different ranges, the relationship between integrity of ellipsoidal zone and BCVA was analyzed. Results Compared with the average logMAR BCVA before treatment, except for 12 months after treatment in group SRD (t=2.104,P=0.053), the average logMAR BCVA after IVR at 3 months, 6 months and 12 months improved in DRT group (t=7.847, 6.771, 6.426;P=0.000, 0.000, 0.000), CME group (t=8.560, 6.680, 5.082;P=0.000, 0.000, 0.000) and SRD group (t=5.161, 3.968, 2.104;P=0.000, 0.001, 0.053). The average logMAR BCVA of the DRT group was lesser than that in CME and SRD group after 12 months treatment (t=–2.043, –3.434;P=0.030, 0.001). The average CFT after IVR at 3 months, 6 months and 12 months reduced significantly in DRT group (t=12.746, 10.687, 9.425;P=0.000, 0.000, 0.000), CME group (t=13.400, 11.460, 10.169;P=0.000, 0.000, 0.000), and SRD group (t=11.755, 10.100, 9.173;P=0.000, 0.000, 0.000). After 12 months of treatment, the average CFT of the SRD group was thicker than that in DRT group and CME group (t=–3.251, –1.227;P=0.003, 0.025); there was significant difference in the integrity of ellipsoidal zone among 3 groups (χ2=1.267,P=0.531). The results showed that there were significant differences in the integrity of ellipsoidal zone with different ranges of BCVA before and after 12 months treatment (χ2=20.145, 41.035;P=0.000, 0.000). Conclusions IVR could significantly improve the visual acuity of different patterns of DME, reduced the CFT, and had the best efficacy in the DRT group. There was relationship between the integrity of ellipsoidal zone and the visual acuity outcomes. Key words: Diabetic retinopathy/therapy; Macular edema /therapy; Angiogenesis inhibitors/ therapeutic use; Antibodies, monoclonal/ therapeutic use; Tomography, optical coherence