Non-mydriatic confocal retinal imaging using a digital light projector

Abstract

A digital light projector is implemented as an integrated illumination source and scanning element in a confocal non-mydriatic retinal camera, the DLP-Cam. To simulate scanning, a series of illumination lines are rapidly projected on the retina. The backscattered light is imaged onto a 2-dimensional rolling shutter CMOS sensor. By temporally and spatially overlapping the illumination lines with the rolling shutter, confocal imaging is achieved. This approach enables a low cost, flexible, and robust design with a small footprint. Qualitative image comparison with commercial non-mydriatic SLOs and fundus cameras shows comparable fine vessel visibility and contrast.

Confocal retinal imaging using a digital light projector with a near infrared VCSEL source

“…2–3 For this application, a DLP LightCrafter 4500 (Texas Instruments Inc., Dallas TX) was configured to display up to 48 fixed line patterns using the internal green and red LED illumination. To visualize the retinal vasculature at high contrast while simultaneously reducing pupil constriction and patient discomfort, the DLP’s broad green LED spectrum was long pass filtered at 570 nm to obtain a 580±10 nm output.…”

Non-mydriatic confocal retinal imaging using a digital light projector

“…Improvements over the previous generation design 18 include the use of a newer DLP (DLP LightCrafter 4500, Texas Instruments Inc., Dallas, TX) which provides greater illumination power and improved timing synchronization. The additional illumination power allows for retinal imaging using yellow light that is filtered from the broad green LED spectrum.…”

Adaptive optics parallel near-confocal scanning ophthalmoscopy

“…The DMD has been considered to have a great potential for parallel confocal microscopy [8] and was recently employed for parallel confocal retinal imaging but not at the cellular level [9, 10]. The DMD used in this study has 1024 × 768 micromirrors which are in a square shape of 10.8 µm × 10.8 µm.…”