Thesis (Ph.D.) - Indiana University, Optometry, 2015Adaptive optics scanning laser ophthalmoscopy (AOSLO) allows high-resolution in vivo imaging of the retina. It provides us a new way to observe and measure the RNFL in vivo. Especially, it opens a possibility of imaging the RNFL in the temporal raphe which can be affected in early glaucoma. The main objective of this thesis is to use an AOSLO to observe and measure the RNFL in the temporal raphe in both normal and glaucomatous subjects. To do this, we first improved the AOSLO imaging with the following efforts: 1) A novel adaptive optics (AO) image processing algorithm was developed to improve the contrast of AO images. 2) A clinical planning module was developed to enhance the data acquisition efficiency, especially for large-scale RNFL imaging. With the improved AOSLO imaging, we investigated the temporal raphe in young healthy subjects. Moreover, we evaluated changes of the RNFL in the temporal retina between patients with glaucoma and age-similar controls. The results shed light on the generalization that has been drawn about the retinal anatomy. We found that the temporal raphe was not a perfect horizontal dividing line. Its angle varied between individuals but was related to the optic disc position. The angle between the temporal raphe and the line that connects the fovea and the center of optic disc was about 170 degrees on average. The temporal raphe changed with aging and glaucoma. Aging increased the separation between nerve fiber bundles in superior and inferior retina, forming a larger gap in the temporal raphe in AO images. In glaucomatous subjects, this gap significantly increased even when the corresponding local visual-field loss was relatively mild. A bundle index, which integrates information about the density and relative reflectivity of nerve fiber bundles, also decreased in glaucomatous subjects. The thesis demonstrated that AOSLO imaging can elucidate the normal anatomy of the temporal raphe in vivo, and the AOSLO can serve as a tool for understanding individual differences of the temporal raphe. This thesis also opened the possibility of using the temporal raphe as a site for glaucoma research and clinical assessment.