Subfoveal choroidal thickness changes after intravitreal ranibizumab injections in different patterns of diabetic macular edema using a deep learning-based auto-segmentation

Purpose To evaluate the effect of intravitreal injection of ranibizumab (IVR) on subfoveal choroidal thickness (SFCT) and its relationship with central macular thickness (CMT) and best-corrected visual acuity (BCVA) changes in eyes with center-involving DME (CI-DME) using a deep learning-based auto-segmentation. Methods This prospective interventional case series included 68 eyes of 68 patients with CI-DME naive to treatment. Morphological optical coherence tomography (OCT) findings of DME were classified into three patterns of structural change: (i) diffuse retinal thickening (DRT), (ii) cystoid macular edema (CME), and (iii) serous retinal detachment (SRD). All patients underwent 3+prorenata IVR. The treated eyes underwent BCVA evaluation and OCT scanning at baseline and months 1, 3, and 6 after the first injection. Then, the choroid layer was measured using a deep learning-based auto-segmentation. Results At baseline, the mean SFCT and CMT for SRD, DRT, and CME groups were 324.68 ± 65.58 μm and 624.37 ± 77.92 μm, 348.91 ± 45.81 μm and 443.5 ± 78.33 μm, 361.4 ± 64.62 μm, and 536.5 ± 66.02 μm, respectively. After anti-VEGF treatment, the SFCT and CMT have decreased by varying degrees. At 3 and 6 months of treatment, there were no significant changes among these groups. There was no correlation between baseline SFCT and the resulting BCVA ( P = 0.670, P = 0.584). There was also no correlation between changes in SFCT and BCVA, CMT ( P = 0.344, P = 0.336). Conclusion After treating CI-DME with IVR, SFCT and CMT significantly decreased. However, there were no significant changes among the SRD, DRT, and CME groups. Trial registration Trial registration: ChiCTR, ChiCTR-ROC-17013360. Registered 13 November 2017, http://www.chictr.org.cn/ChiCTR-ROC-17013360 .