Unsupervised spike sorting for large-scale, high-density multielectrode arrays

electrophysiology; high-density multielectrode array; neural cultures; retina; spike sortin

High-resolution retinal imaging with a compact adaptive optics ophthalmoscope

This thesis presents work on the development of a compact adaptive optics ophthalmoscope to visualize microscopic details of the human fovea. Conventional ophthalmoscopes currently employed in retinal imaging for diagnostic purposes help to detect disorders in real-time; however, their resolution is limited by the optical quality of the last focusing lens, the human eye. In recent years there has been a significant increase in studying retinal alterations, including the complication of non-ophthalmic diseases. In a number of cases, especially for visually impaired and elderly people, when the ocular media become less transparent, fixation is hard for the patients. It is often difficult to repeat the measurements during the usual clinical diagnostic routine; the dynamic changes and imperfection in the optics of the eye also significantly degrade the retinal image quality. In order to resolve cellular level details and hence detect ocular diseases in their infancy, dynamic correction of ocular aberrations is required. Developments in ophthalmoscopy have extended its application to high-resolution imaging using adaptive optics. This technology enables the in-vivo study of finer microscopic structures by dynamically correcting higher-order ocular aberrations. To date, such systems have been large and confined to research laboratory conditions. This thesis investigates the performance of a compact adaptive optics ophthalmoscope built in a cost effective way to provide a diagnostic tool that is more affordable and usable in a general clinical environment. It also highlights some of the problems associated with retinal imaging and discusses the limitations of retinal imaging systems. The results obtained with this system suggest that it is possible to non-invasively detect structural and functional changes of the retina in their early phases of development and enable precise monitoring of the effect of therapies in later clinical research