Quantification of changes in foveal capillary architecture caused by idiopathic epiretinal membrane using OCT-Angiography

Abstract

Purpose : Idiopathic epiretinal membrane exerts vertical and tangential forces on the retina. The latter are dragging the retina from its original position, which can be clearly appreciated when looking at the vascular displacement. In this prospective observational study we quantified the extent and depth of distortion of the foveal capillary architecture due to traction of idiopathic epiretinal membrane (ERM) using optical coherence tomography angiography (OCT-A).

Methods : Multimodal imaging including OCT-A (Angiovue, Optovue) was performed in 26 eyes with idiopathic ERM (71.2 years ± 5.8). Best corrected visual acuity (BCVA), OCT-A vessel density of the foveal (VDfo) and parafoveal (VDp) region were assessed. Based on 6x6mm² OCT-A images, a macular vessel density ratio (MVR=VDf/VDp) was calculated for the superficial (s), deep (d) and full-thickness (f) slabs to assess a depth-resolved, non-invasive evaluation of foveal distortion. The data were subdivided in a group with mild (BCVA < 0,4 logMar) and severe (BCVA > 0,4 logMar) VA reduction due to ERM. Data was compared to age-matched healthy controls.

Results : In all three slabs, MVR was significantly smaller in the control group in comparison with the ERM group: MVRs: 0.64 ± 0.11 vs 0.82 ± 0.11 (p<0.01); MVRd: 0.61 ± 0.08 vs 0.74 ± 0.17 (p<0.01); MVRf: 0.69 ± 0.16 vs 0.81 ± 0.11 (p<0.01). In mild BCVA reduction patients, MVR was significantly higher only in the superficial slab: MVRs: 0.64 ± 0.11 vs 0.74 ± 0.11 (p=0.022); MVRd: 0.61 ± 0.08 vs 0.69 ± 0.13 (p=0.11); MVRf: 0.69 ± 0.16 vs 0.75 ± 0.11 (p=0.13). Whereas in severe BCVA reduction patients, MVR was significantly higher in all slabs: MVRs: 0.64 ± 0.11 vs 0.88 ± 0.08 (p<0.01); MVRd: 0.61 ± 0.08 vs 0.80 ± 0.17 (p < 0.01); MVRf: 0.69 ± 0.16 vs 0.86 ± 0.10 (p<0.01).

Conclusions : Assessing MVR using OCT-A may serve as a tool to quantify the extent and depth of distortion of the foveal capillary architecture due to traction of ERM. BCVA reduction appears to be associated with a greater extent and depth of distortion.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

[A] Exemplary optical coherence tomography angiography (OCT-A) en-face image of a control subject with a superimposed EDTRS grid with close-up of foveal area [B] and corresponding SD-OCT image [C]. [D] Exemplary OCT-A image of an epiretinal membrane (ERM) patient with a superimposed EDTRS grid with close-up of foveal area [E] and corresponding SD-OCT image [F].