Abstract
Purpose:
Fluorescein angiography (FA), an invasive technique, is the golden standard to assess the status of retinal capillaries which reside mainly in the ganglion cell layer (GCL) and inner and outer borders of the inner nuclear layer. Recent advances in optical coherence tomography (OCT) technology have improved the resolution and reduced the speckle noises, leading to the better segmentation of individual retinal layers. We thus investigated the OCT findings of nonperfusion areas (NPA) in diabetic retinopathy (DR).
Methods:
We retrospectively reviewed consecutive 60 eyes of 45 patients suffering from DR, on whom both FA and OCT images with sufficient quality were acquired on the same day. We evaluated the vertical 30-degree sectional images dissecting the fovea obtained by spectral-domain OCT (Spectralis), and especially measured the transverse length of the areas with either the boundary of NFL and GCL/inner plexiform layer (IPL) or the outer plexiform layer (OPL). The lengths of the NPA in FA images by Heidelberg Retina Angiograph 2 (HRA2) were also quantified on the lines corresponding to the OCT images. We then evaluated the relationship between these parameters.
Results:
There was not a definite boundary between NFL and GCL/IPL in the NPA in DR. The length of NPA in FA images was significantly correlated to the transverse length of the areas with no boundary between NFL and GCL/IPL on OCT images (r=0.996, p<0.0001) and, to lesser extent, that of the areas without definite OPL (r=0.370 p=0.0036), in total 60 eyes with DR. Logarithm of minimum angle of resolution visual acuity was associated with the transverse length of the macular areas with either no boundary between NFL and GCL/IPL (r=0.429, p=0.0006) or with no definite OPL (r=0.484, p<0.0001). In addition, the vertical diameter of macular ischemia was associated with the transverse length of the areas with no boundary between NFL and GCL/IPL (r=0.943, p<0.0001), but not with that of the areas without OPL (r=0.189, p=0.2767) in 35 eyes with center-involved diabetic macular edema (DME). Thirteen eyes with enlarged cystoid spaces extending from INL to OPL had larger areas without OPL than 22 eyes without such cystoid spaces (1198±496μm vs. 540±340μm, p=0.005).
Conclusions:
These data suggest that OCT has clinical utility for the evaluation of NPA in DR.
Keywords: 499 diabetic retinopathy •
550 imaging/image analysis: clinical •
572 ischemia