Abstract
Purpose :
Diabetic macular edema (DME) is widely treated with intravitreal anti-VEGF therapies including Aflibercept. However, some DME patients need frequent injections and suffer from irreversible vision loss even after treatment. The aim of this study is to evaluate the association between longitudinal changes of OCT biomarkers and visual outcomes in a tightly controlled and prospective trial cohort.
Methods :
A post hoc analysis evaluated 6 x 6mm2 OCT volume images of 186 DME patients in VISTA trials. At baseline, week 20, and week 52, central subfield retinal thickness (CST), cube volume (CV), intra- and sub- retinal fluid thickness (IRFT and SRFT), and IRF extent were measured with instrument-embedded software and ImageJ, and the presence of pathologic features including disorganization of the retinal inner layers (DRIL), ellipsoid zone/external limiting membrane defect (EZd/ELMd), retinal microaneurysm (MA), hyper-reflective foci (HRF) and epiretinal membrane (ERM) were determined on the images. The relationship between the studied OCT biomarkers, pathologic features and the changes of EDTRS visual scores were analyzed.
Results :
Visual improvement at week 52 was inversely correlated with CST, CV, IRFT and SRFT at week 20 (P=0.009, 0.004, 0.006, and 0.008, respectively). The changes of CST, CV, and IRFT between baseline and week 20 also correlated inversely with visual improvement (P=0.003, <0.001, and <0.001, respectively). None of the OCT biomarkers at week 52 correlated with visual improvement at week 52, and the changes of IRFT and IRF extent between baseline and week 52 correlated inversely with visual improvement (P=0.004 and 0.009). The presence of EZd/ELMd at week 20 and 52 negatively correlated with visual improvement (P=0.02 and 0.03), while the presence of DRIL, MA, HRF, and ERM did not. DME patients with EZd/ELMd had more IRFT and IRF extent than eyes without EZd/ELMd at week 20 (278.8 μm vs 183.2 μm; P<0.001 and 3478 μm vs 1303 μm; P=0.01, respectively).
Conclusions :
The early response of CST, CV, and IRFT are not only indicators of the treatment, but also predictive OCT biomarkers for longitudinal visual outcome. The decrease of IRFT and IRF extent are correlated with the restoration of photoreceptor cells and should be monitored in treatment for DME patients.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.