Abstract
Purpose: :
Central retinal thickness as measured by time domain optical coherence tomography (TD-OCT) does not correlate well with best corrected visual acuity (BCVA). In this study, we aim to correlate specific Spectralis spectral domain OCT (SD-OCT) findings with BCVA in diabetic patients with a history of diabetic macular edema (DME).
Methods: :
Retrospective assessment of the Heidelberg Spectralis SD-OCT scans of consecutive diabetic patients with a history of DME. Patients with vitreomacular traction, significant epiretinal membrane, or any other ocular co-morbidity, such as significant cataract or glaucoma, were excluded.The following specific features on the SD-OCT were assessed:• The presence of foveal cysts involving the inner retina only• The presence of foveal cysts involving the outer retina• The condition of the external limiting membrane (ELM) in the foveal region• The presence of subfoveal serous retinal detachment (SRD)SD- OCT findings were correlated with BCVA. Student t-test was used for statistical analysis.
Results: :
A total of 19% of eyes were excluded due to one of the exclusion criteria, with 50% of those excluded due to vitreomacular traction, 25% due to significant epiretinal membrane formation and the remaining 25% due to other ocular comorbidity. The ELM was intact on SD-OCT of 67.6 % of the studied eyes. The average BCVA in the eyes with an intact ELM was 75.9 letters as compared to 63.7 letters in those with an ELM that was not intact (p=0.018). Foveal involving edema on the SD-OCT scans was present in of 47.1 % of the studied eyes. The average BCVA with foveal involving DME was 67.3 letters, compared to 76.1 letters in patients without foveal involving DME (p=0.031). By excluding those with foveal cysts involving the inner retina only, the average BCVA with foveal involving DME with outer retinal cysts was 66.6 letters, compared to 75.6 letters in patients without foveal involving outer retinal cysts (p=0.037). In this cohort, we did not find any patients with SRD.
Conclusions: :
Diabetic patients with a disrupted ELM have statistical significantly poorer vision. It is unclear whether the condition of the ELM predicts visual acuity outcome following injection based therapies. Further longitudinal study is needed to evaluate prognostic factors for DME.
Keywords: diabetic retinopathy • macula/fovea • imaging/image analysis: clinical