The Correlation between Macular Ischemia by Fundus Fluorescein Angiography and Spectral Domain Optical Coherence Tomography Findings in Diabetic Macular Edema

Abstract
Background: To study the association between the OCT structural changes, and vascular changes around the fovea in FFA in the detection of ischemic diabetic maculopathy.
Material and Methods: A 35 eyes of 25 patients with ischemic and mixed diabetic maculopathy were included as determined by irregular margins of the FAZ in fluorescein angiography. We measured the best-corrected visual acuity (BCVA), central macular thickness, inner retinal layer thickness and the lateral extent of inner segment-outer segment (IS-OS) disruption on SD-OCT images, as well as the FAZ to optic nerve head (FAZ/ONH) area ratio using the Image J program.
Results: The central macular thickness and the inner retinal layer thickness showed no significant correlation with FAZ/ONH area ratio (p=0.161, 0.480 respectively). The mean horizontal and vertical extents of IS-OS disruption were not significantly correlated with FAZ/ONH area ratio (p=0.630 and p=0.732 respectively. The horizontal and vertical extents of IS-OS disruption showed a significant correlation with Log MAR BCVA (r=0.798 and 0.795 respectively, p<0.001 in both). The FAZ/ONH area ratio was positively correlated with LogMAR BCVA but was not statistically significant (p=0.815, r=–0.041).
Conclusion: In patients with diabetic retinopathy, it is not possible to predict FAZ area based solely on the measure-ments assessing volume and thickness or retinal structure evaluation on OCT. Consequently, at present OCT cannot replace FA in the detection of ischemic or mixed diabetic maculopathy.