Adaptive optics scanning laser ophthalmoscope (AOSLO) for precise visual stimulus presentation

Abstract

We present an AOSLO with a dual source retina detector confocal configuration. The beams from two light sources whose wavelengths are 680 nm and 840 nm respectively share the same scanning path but are independently modulated so that they alternately present on only half of each scanning cycle successively and thence project on the retina. The 840 nm source produces real-time high resolution retinal images while the 680 nm source presents AO corrected light stimuli of various configurations. The stimulus position is defined in the images taken with the 840 nm source and the stimulus intensity is controlled by the acoustic-optic-modulator. The longitudinal and transverse ocular chromatic aberrations differed between the two wavelengths and were minimized by adjusting the positions of the source, the retinal plane and the pinholes of the detectors to be exactly conjugate with each other in both light channels, ensuring that both beams accurately focus on the lateral and longitudinal position of interest in the retina. In the human eye, with a field of view of 1.2 degree, the AOSLO can deliver and maintain the stimulus on a single foveal cone with the 3-D positioning precision as high as 0.7 micron × 0.7 micron × 60 micron.

Footnotes

 This work is funded by the National Institutes of Health Bioengineering Research Partnership Grant EY014375, the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement #AST-9876783, and NEI grant EY10217.