Abstract
Purpose:
To quantify the mean signal intensity of fundus autofluorescence (FAF) in individual subfields of Early Treatment Diabetic Retinopathy Study (ETDRS) grid and to evaluate its association with visual function and optical coherence tomography (OCT) findings in diabetic macular edema (DME).
Methods:
We retrospectively reviewed consecutive 103 eyes of 78 patients with center-involved DME and 30 eyes of 22 patients without DME for whom short-wavelength autofluorescence (SW-AF) images and spectral-domain optical coherence tomography (SD-OCT) images of sufficient quality were obtained. SW-AF images were acquired using Heidelberg Retina Angiography 2 and retinal sectional images were obtained by Spectralis OCT. We quantified the fluorescein intensity in the central 1-mm subfield and the parafoveal (1-3mm) subfields (nasal, superior, inferior, and temporal) of ETDRS grid, and calculated the relative intensity, comparing to the intensities within the optic disc (as 0) and outside the ETDRS grid (as 1). We evaluated its relationship with logarithm of minimum angle of resolution visual acuity (logMAR VA) or qualitative and quantitative OCT findings.
Results:
Eyes with center-involved DME had lower levels of FAF signal intensity in the parafoveal subfields (P<0.01 in all subfields) but not in the central subfield than those without DME. The fluorescence intensity in the parafoveal subfields was negatively correlated to logMAR VA (R=-0.454, P<0.001, R=-0.414, P<0.001, R=-0.370, P<0.001, and R=-0.381, P<0.001 in the nasal, superior, inferior, and temporal subfields, respectively) and the mean retinal thickness in the corresponding subfields (R=-0.423, P<0.001, R=-0.504, P<0.001, R=-0.493, P<0.001, and R=-0.471, P<0.001 in the nasal, superior, inferior, and temporal subfields, respectively). There were no associations of the FAF intensity in the parafoveal areas with the presence of foveal cystoid spaces or serous retinal detachment. The fluorescence level in the central subfield was related to the presence of foveal cystoid spaces (0.243±0.096 vs. 0.148±0.074, P=0.002), but not to logMAR VA or the retinal thickness in the corresponding subfield.
Conclusions:
These data suggest that quantified FAF in the parafovea has diagnostic significance and clinical relevance in DME.
Keywords: 499 diabetic retinopathy •
505 edema •
550 imaging/image analysis: clinical