Adaptive optics scanning laser ophthalmoscope for stabilized retinal imaging

Abstract

A retinal imaging instrument that integrates adaptive optics (AO), scanning laser ophthalmoscopy (SLO), and retinal tracking components was built and tested. The system uses a Hartmann-Shack wave-front sensor (HS-WS) and MEMS-based deformable mirror (DM) for AO-correction of high-resolution, confocal SLO images. The system includes a wide-field line-scanning laser ophthalmoscope for easy orientation of the high-magnification SLO raster. The AO system corrected ocular aberrations to <0.1 μm RMS wave-front error. An active retinal tracking with custom processing board sensed and corrected eye motion with a bandwidth exceeding 1 kHz. We demonstrate tracking accuracy down to 6 μm RMS for some subjects (typically performance: 10-15 μm RMS). The system has the potential to become an important tool to clinicians and researchers for vision studies and the early detection and treatment of retinal diseases.

Photoreceptor counting and montaging of en-face retinal images from an adaptive optics fundus camera

“…First applied to a conventional fundus camera by Liang et al, 1 AO has been subsequently applied to confocal laser scanning ophthalmoscopes [2][3][4] and most recently to optical coherence tomography. [5][6][7] Such systems have enabled cone classing of individual photoreceptors, 8,9 measurement of the directionality of individual cones, 10 the temporal 11,12 and wavelength properties 13 of cone reflectance, and the characterization of the cone mosaics in forms of sex linked dichromacy.…”

Adaptive Optics

“…Eye tracking softwares correct for micro-movements of the eyes and enable imaging even in non-mydriatic states. 7 Adaptive optics Optical coherence tomography (AO-OCT) -The peculiarity in OCT is that the axial and lateral resolution is decoupled. Axial resolution is limited by the coherence properties of light.…”

Eye-pupil displacement and prediction: effects on residual wavefront in adaptive optics retinal imaging

“…In recent years, such so-called 'pupil trackers' (PT) camera-based devices have been integrated into retinal imaging systems and have been used for a number of purposes, for example to detect and forecast where a subject is looking within a scene. In 2006, Hammer et al used a pupil tracker integrated into a scanning laser ophtalmoscope system to actively compensate pupil movements in real time using a flat two-degrees of freedom field stabilization mirror [17]. A WFS-based pupil tracker, which eliminates the need for a separate PT camera, was proposed in [18].…”