Abstract
Purpose :
Disorganisation of the inner retina (DRIL), disruption of the ellipsoid layer, enlarged foveal avascular zone (FAZ) and reduced macular vascular density (VD) are associated with poor visual acuity (VA). In this study, we evaluated the relative contributions of these markers in explaining poor visual acuity.
Methods :
Optical coherence tomography (OCT), OCT-angiography (OCT-A) and VA were evaluated in eyes with central retinal vascular occlusion or proliferative diabetic retinopathy with no or resolved macular oedema. The eyes were categorised as those with good (BCVA ≥ 78 ETDRS letters) and poor visual acuity (BCVA<78 ETDRS letters). The OCT images were graded for presence or absence of DRIL and disruption of the ellipsoid layer at the fovea. Superficial and deep FAZ size were measured using imageJ. Vessel densities both at the superficial and deep vascular plexi were computed using adaptive thresholding based on local mean intensity. Multivariable logistic regression analysis was used to study the strength of relationship of these markers with poor visual acuity. P values of <0.05 were considered as statistically significant. ROC curves were examined and area under curve (AUC) is reported.
Results :
43 eyes were included in this study with 22 eyes having VA of 78 ETDRS letters or better. Seventeen eyes were positive for DRIL and associated with poor visual acuity (p=0.0037). Six eyes had sub-foveal ellipsoid layer disruption which did not correlate with poor visual acuity and only 2 eyes had both features. The mean superficial and deep FAZ areas were 0.48 ± 0.22 mm2 and 0.75 ± 0.36 mm2 respectively. The Spearman’s co-relation coefficient of FAZ area, superficial r= -0.3, deep r= -0.21, showed a negative co –relation with visual acuity (p<0.05). Multivariable logistic regression analysis after adjusting for ellipsoid and superficial VD showed that only DRIL (OR= 15.02, P=0.002) is an independent factor of poor visual outcome. The AUC for eyes with DRIL with no disruption of ellipsoid layer was 0.717.
Conclusions :
DRIL is a more frequent imaging marker than foveal ellipsoid layer disruption in retinal vascular disease and is an independent predictor of poor visual acuity. In this study with a small sample size, disruption of ellipsoid layer and decreased macular vessel density were not markers of poor visual outcome.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.