Abstract
Purpose:
The choroidal layer suffers changes in the diabetic disease, those can affect external retina, yielding different forms and degrees of macular affection as edema and/or ischemia. An anatomic aspect of the choroidal layer as its thickness can be related with the retina status in its different types or patterns of macular edema. The aim of this study was to determine the sub-foveal choroidal thickness (CT) in the different kinds of diabetic macular edema (DME) by Optical Coherence Tomography (OCT).
Methods:
Prospective, observational, cross sectional study; involving 47 eyes of 27 diabetic patients with macular edema without traction component or any previous treatment, selected in a 5 months period. DME was confirmed by FFA. Measurements of the CT were done at the subfoveal region in the cross sectional scans every 500µ until 2500µ from the center of the fovea using RTvue SD-OCT. All measurements were performed by a senior optometrist and the authors. The results were submitted to SPSS 20 statistical program and to establish significative difference we use the Student t-test.
Results:
Choroidal thickness average was 226 µ. 31.91% (15 eyes) had a CT less than 200µ (values considered less than normal in previous studies), out of which 73.33% (11 eyes) had spongiform edema. 63.83% (30 eyes) had CT in the range of 200-320µ (considered normal), the spongiform component was present in 83.33% (25 eyes) and the cystoid component in 46.66% (14 eyes) of them. 4.26% (2 eyes) had CT more than 320µ with both spongiform and cystoid components. 10 eyes had serous retinal detachment (SRD), out of which 60.0% (6 eyes) had both, spongiform and cystoid components. CT average in DME with SRD was 269µ, which is major than DME without SRD that was 213µ.
Conclusions:
Cystoid and spongiform edema are not related with a determined value or range of choroidal thickness in DME, but in cases of DME with SRD the choroidal thickness was greater than the average thickness in cases without SRD and this difference was statistically significant. Nonetheless CT average in both groups were within the considered normal range.
Keywords: 452 choroid •
499 diabetic retinopathy •
585 macula/fovea