Purpose
To demonstrate new features of a dedicated multi-mode adaptive optics platform for application to in vivo imaging of rodent models of human eye disease.
Methods
Anesthetized Sprague-Dawley albino rats were imaged with a MAOS small animal imaging platform with simultaneous high-speed AO-SDOCT and high-resolution confocal AOSLO or fluorescence AOSLO (fAOSLO). Novel platform design elements include such features as high dynamic range wavefront sensing with static or dynamic AO correction, integrated Badal optometer with a high-stroke deformable mirror (Alpao DM-97) and path-length-locked OCT reference arm for flexible, high-NA AO imaging in desired retinal layers, and co-scanning AO-OCT/SLO rasters. This configuration provides significant benefits to imaging sensitivity and ease of use in anesthetized small animals. Either the OCT beam or an SLO reflectance beam at 760nm serves as the AO beacon. A 532nm laser in reflectance/fluorescence testing enabled autofluorescence imaging with insertion of an emission filter. Stable alignment of the subjects’ eyes was achieved using a flexible positioning stage.
Results
The MAOS simultaneously acquired AO-SDOCT with reflectance/ fluorescence channels in up to 15x15deg scans (~1.5mm at the retina). AO-SDOCT imaging (SLD, 600μw, 850nm, 110nm fwhm) used a custom spectrometer (with Basler Sprint camera) at up to 100 B-scans/sec—fast enough for blood flow mapping. AO-SDOCT volumes were recorded at 1 to 5 seconds/frame, while reflectance AOSLO scans at 760nm (SLD, 250μw) or 532nm (250μw) used in preliminary reflectance/fluorescence testing, were also acquired with APD detection and a data acquisition card (NI DAQ). Initial AO correction testing with new wavefront sensor (see figure) and AO control algorithm showed >6dB improvement in image brightness. Low speed scans showed high sensitivity with minimal residual motion artifacts in anesthetized rats. Axial location of peak brightness in AO-SDOCT images also provides guidance for best focus of the parfocal AOSLO/fAOSLO beams at any desired layer.
Conclusions
New high resolution imaging tools such as the MAOS platform have the potential to be an important part of animal research, from basic vision research to commercial drug discovery.
Keywords: 630 optical properties •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
599 microscopy: light/fluorescence/immunohistochemistry