Development of a Spectral Imaging Device for Imaging of the Fundus

The purpose of this project was to design and develop a device capable of viewing different spectral bands for imaging of the fundus. This required the creation of a novel spectral imaging device capable of dynamically reconfigurable spectral bands. In addition, the viewing of the fundus necessitated that a compact optical device capable of real time observation of the fundus was constructed. The formation of these two devices will lay the foundation for a future integration between them. This in turn, will allow for the observation of the fundus under different spectral conditions and may reveal early signs and markers of potential damage to the retina. In particular, the imaging of the retinal nerve fiber layer is desired as some spectral bands of these imaged bundles may provide insight into certain eye diseases in their early stages. To aid with the analysis of fundus imaging, the use of optical coherence tomography (OCT) to provide a high-resolution subsurface cross-sectional imaging of living tissue and the creation of a compact retinal scanning device were also studied. Vacuum assisted microfluidics capable of producing integrated micro optical devices with features of less than 10 microns were also investigated in the hopes of replacing the rather large and bulky conventional spectrometer used in OCT. Here isolated single mode waveguides with feature sizes of less than 7 microns were successfully fabricated and a design for a compact integrated spectrometer using a planar concave grating was examined. The spectral imaging device demonstrated the ability of separating spectral bands to as narrow as 20 nm bandwidths and the galvanometer scanning mechanism involved in this system could scan across the whole visible wavelength range in as fast as a few hundred milliseconds. The compact fundus scope was able to image the fundus and a future integration with the spectral imaging device is planned. Retinal images were successfully achieved through the conventional OCT system and the compact optical retinal scanner should allow for a relatively simple integration with the spectral imaging device and the attached fundus scope. A future proposed device combining a fundus scope and the spectral imaging device with the OCT retinal scanner should allow for a quick dynamic imaging of the retina and provide a better insight into eye diseases especially in their earlier stages