Abstract
Purpose :
Neurodegeneration and vascular changes are hallmarks of diabetic retinopathy. In this study, we ask whether microvascular changes in optical coherence tomography angiography (OCTA) of the macula and optic disc correlate with severity of diabetic retinopathy (DR) and diabetic macular edema (DME), and whether these changes correlate with structural optical coherence tomography (OCT).
Methods :
We recruited patients with diagnosis of diabetes mellitus and healthy controls in a prospective, case-control study at a single institution. We performed a complete ophthalmologic exam, OCT imaging with measurements of retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC), and angiographic analyses of the macula and optic disc, which include vessel diameter (VD), vessel area density (VAD), vessel skeleton density (VSD), vessel perimeter index (VPI), vessel complexity index (VCI), and flow impairment (FI).
Results :
We recruited 124 diabetic patients (216 eyes) and 67 controls (94 eyes). OCTA analysis of the macula showed that diabetics had significantly reduced VD (p=3.87E-07), VAD (p=0.04), VSD (p=1.62E-06), VPI (p=0.0001), VCI (p=4.14E-06), and significantly increased FI (p=1.37E-06). OCTA analysis of the optic disc also revealed significant reduction in VD (p=0.005), VAD (p=0.029), VSD (p=0.0001), VPI (p=0.001), VCI (p=0.0005), and significantly increased FI (p=2.03E-07). Stratification by DR grading1 showed a significant linear trend for OCTA flow impairment with higher values corresponding to increasing levels of retinopathy in both macula (p<0.0001) and disc (p<0.0001). Upon stratification into DME grading, OCTA flow impairment values showed a similar significant trend with higher values corresponding to active and quiescent DME in both macula (p<0.0006) and disc (p<0.0010). The control and diabetic groups had similar RNFL (control: 90.0±1.0, diabetic: 92.2±0.9, p=0.13) and GCC thickness (control: 80.0±0.7, diabetic: 80.0±0.6, p=0.90).
Conclusions :
Diabetic patients exhibited significant worsening of angiographic measurements of the macula and optic disc despite no significant change in RNFL and macular GCC thickness. The severity of OCTA changes corresponded with higher levels of diabetic retinopathy (Grade 4, proliferative diabetic retinopathy) and macular edema (Grade 1, active DME, and Grade 2, quiescent DME).
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.