Entoptic visualization of the retinal vasculature near fixation.

The authors review (1) the range of techniques used to study the retinal vasculature near the fovea, (2) describe the need and rationale for noninvasive in vivo monitoring of the retinal vasculature, (3) present theoretic and practical considerations which show that entoptic visualization of the smallest capillaries near the fovea is optimized by a small short-wavelength source (1 mm or less) rotating at 3.5 hertz in a circular path (radius 2 mm) imaged in the plane of the eye's entrance pupil, and (4) discuss the feasibility of using these techniques as a research and clinical tool.