Dual-beam optical coherence tomography and topography of the human eye: a clinical feasibility study

Partial coherence interferometry, a new optical non-invasive technique, that has been developed for high precision measurements of intraocular distances, has been extended to a 2D imaging instrument, called scanning partial coherence interferometer. Since the improved version of this interferometric technique is capable of performing measurements of intraocular distances at arbitrary angles between vision axis and measurement direction, or along preselected linear or circular scans in equidistant measurement points, tomographic and topographic images can be obtained, containing information about the contour and the thickness profile of different retinal structures, e.g., the retinal thickness, the retinal nerve fiber layer thickness or the thickness of choroidal layers. We report on first preliminary clinical results of measurements of the retinal thickness on healthy subjects. Furthermore the papillary retinal nerve fiber layer thickness distribution of glaucoma patients was obtained and compared with measurements performed on healthy eyes. These results were documented and correlated with topographic maps of the optic disc obtained with a Heidelberg Retina Tomograph and with visual field testing performed by automatic perimetry.