Abstract. Images from high-resolution scanning ophthalmic instruments are significantly distorted due to eye movement. Accurate image registration is required to successfully image subjects who are unable to fixate due to retinal conditions. Moreover, all scanning ophthalmic imaging modalities using adaptive optics will benefit from image registration, even in subjects with good fixation and anaesthetized animals. Transformation functions used to map two images could in principle be very complex. Here, we show that when the scanning in ophthalmic instruments is sufficiently fast with respect to the speed of involuntary eye movement, these mapping functions become the addition of a linear term and a single variable function. Then, based on experimental data on eye movement amplitude and speed of the fixating eye, minimum sampling frequencies for these instruments are discussed. Finally, a simple method for estimating the image transformation functions by taking advantage of the finite bandwidth of the motion signals is presented.
Imaging of the retinal vascular structure and perfusion was explored by confocal illumination and nonconfocal detection in an adaptive optics scanning light ophthalmoscope (AOSLO), as an extension of the work by Chui et al. [Biomed. Opt. Express 3, 2537 (2012)]. Five different detection schemes were evaluated at multiple retinal locations: circular mask, annular mask, circular mask with filament, knife-edge, and split-detector. Given the superior image contrast in the reflectance and perfusion maps, the split-detection method was further tested using pupil apodization, polarized detection, and four different wavelengths. None of these variations provided noticeable contrast improvement. The noninvasive visualization of capillary flow and structure provided by AOSLO split-detection shows great promise for studying ocular and systemic conditions that affect the retinal vasculature.
, who's guidance and vision made this work possible. I would like to thank my entire committee for taking the time to review my thesis and give feedback. Finally I would like to acknowledge the countless hours of hard work by the many people in the Dubra lab.
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