Model eye tool for retinal optical coherence tomography instrument calibration

Abstract

Optical coherence tomography (OCT) has been extensively used as noninvasive tool for biological tissues owing to its three-dimensional imaging ability and high axial resolution. OCT quality assurance is vital in these occasions to keep the reliability and accuracy in medical diagnosis. It is necessary to develop a calibration tool for OCT product manufacture, calibration, and quality control. A practical tool is demanded in the OCT quality control and calibration of OCT. So far, there is no such a practical tool that can test all the key parameters of OCT. We design and fabricate a model eye tool, which has this function. The model eye comprises a doublet lens, a single filament, a piece of glass plate and the microsphere-embedded phantom. The doublets lens is bonded by two pieces of planoconvex lenses in the plane position. The first lens focuses parallel light onto the rear surface of the second lens. The rear surface marked with concentric circles serves as retina to measure the angular field of view (FOV). The small flat surface on the peak of the second lens is used to test signal to noise ratio (SNR). The single filament with 125μm diameter is used to check the co-alignment of preview and OCT scan. The empty chamber between the small plane of the second lens and the first surface of glass plate is used to measure the depth scaling of the OCT. The microspheres of 1μm diameter distributed uniformly in the phantom, which can test the lateral and the axial resolution of OCT equipment. Experimental results are presented to show the validity of the proposed tool. It is shown that the tool is able to be used in the calibration and quality control of retinal OCT.

Keywords

• optical coherence tomography
• model eye
• microsphere-embedded phantom