Changes in the diabetic choroidal vasculature: scanning electron microscopy findings.

Scanning electron microscopy (SEM) was used to study vascular casts of 20 cadaver eyes according to our previously described technique. All eyes were taken from patients with long-standing diabetes mellitus type I. The SEM findings in the choroidal vessels included: increased tortuosity, dilation and narrowing, hypercellularity, vascular loop and microaneurysm formation, "drop-out" of choriocapillaries, and sinus-like structure formation between choroidal lobules. To our knowledge, these are the first SEM studies of the vascular casts performed on human cadaver eyes from diabetics.