Author: Costanza Barresi (Italy)
Co-authors: Enrico Borrelli, Domenico Grosso, Giorgio Lari, Riccardo Sacconi, Francesco Bandello, Giuseppe Querques
Diabetic macular edema (DME) represents a frequent complication of diabetes as it occurs in nearly 12% of patients with diabetic retinopathy (DR). Although anti-vascular endothelial growth factor (VEGF) therapy has significantly improved visual outcomes in these patients, a group of subjects is still characterized by worse visual acuities even after successful treatment. The aim of this study was to perform a qualitative and quantitative analysis on structural optical coherence tomography (OCT) images from DME eyes obtained more than 5 years after the initiation of anti-VEGF treatment to characterize morphologic characteristics correlating with good and poor long-term visual outcomes.
Retrospective study at San Raffaele Scientific Institute, Milan, Italy.
In this study, subjects 18 years of age and older with center-involved DME in at least one eye were identified from the medical records. Subjects were required to have a long-term follow-up (≥5 years) and evidence of resolved DME (i.e restoration of the foveolar depression with a central macular thickness (CMT) <315 µm) in at least one visit after 5 years of follow-up visits following the initiation of anti-VEGF therapy. The last visit with OCT evidence of resolved DME was considered as the study visit and was used for morphologic analysis. OCT images at the study visit were graded for qualitative features previously proposed as reflecting a distress of the neuroretina in patients with DME, as follows: (i) integrity of the ellipsoid zone (EZ) and external limiting membrane (ELM) bands within the foveola; (ii) integrity of the retinal pigment epithelium (RPE) within the foveola; (iii) presence of disorganization of retinal inner layers (DRIL) in the 1 mm central fovea. A quantitative topographical assessment of the inner (combination of nerve fiber and outer plexiform layers) and outer retinal (combination of the outer plexiform and outer nuclear layers) thicknesses was also provided.
Sixty-one eyes (50 patients) were included and divided into two subgroups according to the visual acuity (VA) at the inclusion visit, yielding a group of 24 eyes with a VA<20/40 (“poor/intermediate vision” group), and 37 eyes with a VA≥20/40 (“good vision” group). The ELM and RPE bands were more frequently disrupted/absent in the “poor/intermediate vision” group (P=0.003 and P=0.019). Similarly, DRIL was more prevalent in the “poor/intermediate vision” group (P=0.013). The foveal and parafoveal outer retinal thicknesses were reduced in poor/intermediate vision eyes (P=0.022 and P=0.044). No differences in perifoveal outer retinal thickness and inner retinal thicknesses were detected between groups. Multivariate stepwise linear regression analysis demonstrated that the strongest associations with BCVA were with appearance of the RPE (P<0.0001), parafoveal outer retinal thickness (P=0.035), foveal outer retinal thickness (P=0.046), and appearance of the ELM (P=0.048).
In a real-world setting, long-term visual outcomes are generally favorable, and many eyes maintain better than 20/40 vision after >5 years from the initiation of anti-VEGF therapy. More importantly, this longitudinal study provides OCT biomarkers associated with long-term visual outcomes in eyes with DME treated with anti-VEGF. Our findings may be employed to guide the optimal anatomic target in patients with this disorder.
I have no financial disclosure