Confocal scanning laser ophthalmoscope

Abstract

A confocal scanning imager moves an illumination spot over the object and a (virtual) detector synchronously over the image. In the confocal scanning laser ophthalmoscope this is accomplished by reusing the source optics for detection. The common optical elements are all mirrors-either flat or spherical-and the scanners are positioned to compensate astigmatism due to mirror tilt. The source beam aperture at the horizontal scanner is small. Light returning from the eye is processed by the same elements, but now the polygon's facet is overfilled. A solid-state detector may be at either a pupillary or retinal conjugate plane in the descanned beam and still have proper throughput matching. Our 1-mm avalanche photodiode at a pupillary plane is preceded by interchangeable stops at an image (retinal) plane. Not only can we reject scattered light to a degree unusual for viewing the retina, but we choose selectively among direct and scattered components of the light returning from the eye. One (of many) consequences is that this ophthalmoscope gives crisp and complete retinal images in He-Ne light without dilation of the pupil.

Scanning Laser Ophthalmoscope in the Management of Age-related Macular Degeneration

“…22 The improved capabilities of the cSLO, as previously mentioned, was achieved by modifying the aperture of the direct SLO to allow only the light reflected from the fundus to be detected, reducing the influence of scattered light and improving image quality. 11,16 In contrast to the confocal approach, it was determined that by blocking light reflected from the fundus with a central stop on the aperture, only laterally scattered light is detected. 23 This was the concept that led to the indirect SLO, which was designed to detect light scattered by lesions on the retina.…”

Scanning laser ophthalmoscope-evoked multifocal ERG (SLO-mfERG) in patients with macular holes and normal individuals

“…This new technique offers the possibility to generate a stimulus array with a helium-neon laser under simultaneous control of fixation. [12][13][14][15][16][17] The purpose of this study was to assess the feasibility of this method to measure focal retinal function or dysfunction under simultaneous control of fixation.…”

Fast and noninvasive fluorescence imaging of biological tissues in vivo using a flying-spot scanner

“…The FSS is based on single-pixel illumination and detection and its principal components are a low-power light source, a pair of horizontal and vertical scanning mirrors to deflect the light in these respective directions on the tissue surface, and a photo multiplier tube (PMT) detector. The FSS is similar in principle to the commercially available scanning laser ophthalmoscope (SLO) [14]. The SLO is an imaging device designed to view the inner parts of the human eye.…”