Lains I, et al. - Using swept-source optical coherence tomography, experts comparatively inspected the choroidal thickness (CT) of diabetic eyes (different stages of disease) vs the controls. A significant reduction of CT in proliferative DR (PDR) compared with controls was displayed by the swept-source optical coherence tomography. In the DR eyes, the choroid appeared to be thinner in the foveal region as compared to the eyes without retinopathy.