Abstract
Abstract: :
Purpose: The aim is to get the true (refraction corrected) 3D geometrical structure of the anterior chamber of an eye with the possibility of its visualization and the ability of the arbitrary intra ocular distances measurements. Methods: We have used standard time-domain OCT to measure 3D Tomograms of the anterior chamber (including cornea and both lens interfaces) of an artificial model eye and a porcine eye in vitro. These data were then corrected for refraction with the help of a novel 3D ray-tracing algorithm based on Snell’s law. The refractive indexes of the eye tissues were taken from a Le Grand eye model and were assumed to be the same for the porcine eye. Our refraction correction algorithm uses first 36 terms of Zernike Polynomials for describing the shape of each of the interfaces. We sample the object at 400 points arranged in a hexagonal pattern. The transversal separation between the points was set to 0.35 mm. The axial resolution amounted to 25 µm. The full depth range of the OCT system is maximally 4 cm. With a scan rate of 20 scans/seconds we can record a full 3D tomogram within 20 seconds. The further 3D visualization allows for measurements of arbitrary intraocular distances. It gives also a general view of the geometrically true topography of the refractive eye surfaces of the full anterior chamber. Results: The refraction corrected 3D structures of the anterior chamber of an eye are calculated. We also have the possibility to visualize the refraction corrected data and to measure arbitrary intraocular distances. The figures below show 3D visualizations of the cornea, and refraction corrected anterior chamber structure of an artificial eye model respectively.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • image processing • anterior chamber