Fluorescein Intensity Of Cystoid Spaces Is Negatively Correlated To Optical Coherence Tomographic Reflectivity In Diabetic Macular Edema

Abstract

 

Purpose:

 

Diabetic macular edema (DME) occurs as a result of disruption of the blood-retinal barrier (BRB), which leads to increased accumulation of fluid within retinal parenchyma of the macula. We herein investigated the association between fluorescein angiography (FAG) findings and the characteristics delineated by spectral-domain optical coherence tomography (SD-OCT) in DME.

 

Methods:

 

Consecutive series of 139 eyes from 110 patients suffering from DME were included in this study. All eyes were examined by SD-OCT (Spectralis OCT; Heidelberg Engineering) and FAG (Heidelberg Retina Angiography 2; HRA2) on the same day. The reflectivity in the contents of individual cystoid spaces or serous retinal detachment (SRD) was graded into three levels in OCT images within 500µm centered on the fovea. The fluorescence intensity in cystoid spaces, pooling, in the late phase was graded into two levels; ‘marked’ intensity means that the average fluorescence level was that in nearby retinal venules or more, and ‘mild’ one corresponds to mild hyperfluorescence less than nearby venules.

 

Results:

 

SD-OCT delineated 188 cystoid spaces in 105 eyes (75.5%) within 1mm centered on the fovea. 9 cystoid spaces (4.8%) presented high reflectivity, 119 (63.3%) low, and 60 (31.9%) medium. The highly reflective cystoid spaces showed significant association with ‘mild’ fluorescence pooling (p<0.01). Furthermore, 50 cystoid spaces (26.6%) showed heterogeneous reflectivity, which presented ‘mild’ fluorescence intensity with significant frequency (p<0.01). SRD was depicted in SD-OCT images of 23 eyes (16.5%). One (4.3%) showed high reflectivity, 2 (8.7%) medium, and 20 (87.0%) low. We could not at all find the fluorescein pooling corresponding to the area of retinal detachment.

 

Conclusions:

 

The novel association between hyperfluorescence and optical coherence tomographic reflectivity suggests that the contents of cystoid spaces are heterogeneous and affect the intensity of fluorescein pooling in DME.

 

Keywords: diabetic retinopathy • edema