This proposal seeks to elucidate the structure-function relationships between visual field threshold sensitivity and the structural features of the retinal layers. The study will address which structural properties of the layers of the macula - obtained from three-dimensional image analysis of spectral domain optical coherence tomography (3-D OCT) - are associated with visual sensitivity, a measure of function. Specifically, we will investigate how structural measures of localized columnar regions of the macula, including layer thickness and texture, are associated with the threshold sensitivity of those macular columns measured at corresponding locations in the central 10 degrees with 10-2 perimetry. The project is driven by an important clinical problem - the poor reliability and reproducibility of the visual field as a measure of irreversible damage to the retinal ganglion cells and their axons in optic neuropathies including glaucoma. If the expected associations are confirmed by 3-D image analysis of spectral domain OCT of the macular layers, the new approach has the potential to become an objective and reproducible addition to the functional assessment of the status of damage. The overriding hypothesis motivating the proposed research is that macular visual sensitivity can be predicted from macular structure and texture properties as imaged and quantified by comprehensive analysis of 3-D spectral-domain OCT. We have identified the following specific aims:
Aim 1 : Refine and validate our existing method of segmenting retinal layers from 3-D spectral OCT images;derive global and focal structural indices, such as thickness and texture, of each retinal layer in the peripapillary and the macular regions of the retina in normal eyes and in eyes with central visual field damage from glaucoma and anterior ischemic optic neuropathy.
Aim 2 : Determine how the structural indices derived from the retinal ganglion cell and other intraretinal layers in the macula correlate with the thickness of the corresponding ganglion cell axons in the retinal nerve fiber layer. This will be demonstrated in normal eyes and in eyes with a wide range of macular sensitivity loss from glaucoma and anterior ischemic optic neuropathy.
Aim 3 : Model the structural-functional relationships in the macula by comparing and registering visual sensitivity at 68 locations (Humphrey 10-2 test averaged over 3 repeats) with their corresponding structural indices of the segmented layers. Derive a predictive model of function from structural properties of the macular layers in the same set of normal and damaged eyes used in Aim 2. The work will be performed in in-vivo acquired 3-D OCT images accompanied by visual field sensitivity test data from 30 normal, 5 glaucoma, and 20 unilateral anterior ischemic optic neuropathy subjects.
Three dimensional spectral OCT imaging provides a wealth of information about the morphology and tissue characteristics of retinal layers. We propose to study structural and functional relationships of the macular intraretinal layers using this new 3-D OCT imaging device. This study has potentially important consequences for glaucoma, anterior ischemic neural neuropathy, and other retinal disease diagnosis and treatment.
Showing the most recent 10 out of 71 publications
