Abstract
Purpose:
To evaluate choroidal thickness (CT) as measured by enhanced-depth imaging optical coherence tomography (EDI-OCT) in patients with untreated diabetic macular edema (DME), and after focal laser or anti-vascular endothelial growth factor (VEGF) therapy.
Methods:
This is a retrospective cross-sectional study of 172 eyes from 98 consecutive diabetic patients (51 male, 47 female; mean age 60.2) with and without DME who had Heidelberg Spectralis EDI-OCT at the Duke Eye Center from October 2011 to October 2012. Semi-automated segmentation of the choroid was performed and CT was measured at the fovea. Stepwise multivariable linear regression was performed to evaluate the association of CT with age, type of diabetic retinopathy (NPDR vs. PDR), HbA1c, visual acuity, and refractive error. Subfoveal CT was compared between eyes with untreated DME (n=35) and without DME (n=60) using a general linear model to adjust for age. Among eyes with DME, choroidal thickness after focal laser (n=27), intravitreal anti-VEGF injections (n=7), or both treatments (n=13) were compared with untreated DME (n=35). Finally, the relationship between subfoveal CT and central foveal thickness (CFT) and macular volume (MV) was assessed.
Results:
Subfoveal CT in all eyes correlated most with age (β=-2.712, p<0.001, adjusted R2 0.161), but not type of diabetic retinopathy, HbA1c, visual acuity, or refractive error. When adjusted for age, mean subfoveal CT in eyes with untreated DME was 261.75 +/- 86.18μm, while those without DME was 268.48 +/- 86.13μm (p=0.715). Mean subfoveal CT in eyes with DME treated with focal laser (233.61 +/- 68.11μm), anti-VEGF therapy (237.43 +/- 76.38μm), or both (245.52 +/- 76.06μm) did not differ significantly from untreated DME (p=0.893). Among eyes with DME, there is no clear relationship between subfoveal CT and CMT (p=0.337) or MV (p=0.281).
Conclusions:
Subfoveal CT varies with age, but may not differ significantly between eyes with and without DME. Furthermore, CT may not be altered by treatment with focal laser, anti-VEGF therapy, or both. This study is limited by its retrospective, cross-sectional nature, however these results suggest that choroidal thickness may not be an important factor in the pathophysiology of diabetic macular edema.
Keywords: 452 choroid •
499 diabetic retinopathy •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)