Mapping choroidal thickness in patients with type 2 diabetes

Abstract

ObjectiveTo determine and compare topographic features of the choroidal thickness (CT) between patients with type 2 diabetes (T2D) and age-matched healthy controls based on swept source-optical coherence tomography (SS-OCT). DesignCross-sectional study. Participants96 T2D patients and 33 healthy individuals aged above 18 years and with an axial length (AL) lower than 26 mm were included. MethodsA macular 6 × 6 mm cube, comprising 900 200 × 200 µm cubes, was scanned with SS-OCT. The choroid was automatically segmented using the segmentation algorithm. Three-dimensional maps were created to represent the choroid. The scanned area was divided into different zones based on CT, and equivalent zones were compared between groups. ResultsMean age (standard deviation) in the control group was 66.83 (7.3) years, and that of the T2D group was 67.94 (7.9) years (p = 0.48). Both groups were similar regarding AL and spherical equivalent. Overall, CT was significantly thinner in the T2D group; it was 203.78 (53.40) in healthy individuals and 169.98 (63.22) in T2D patients (p = 0.01). Outside the fovea, the mean CT was thicker in the superior hemiretina and decreased inferiorly, temporally, and nasally, with minimum thickness in the most distant points from the fovea. ConclusionsChoroidal thickness follows an ellipsoid pattern in both nondiabetic and diabetic eyes, with diabetic eyes showing thinner measurements diffusely. Understanding these differences is important for future studies aimed at understanding the pathophysiological underpinnings of diabetic retinopathy.