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 125[Formula: see text][Formula: see text]m 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 1[Formula: see text][Formula: see text]m 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.

Opto-Mechanical Eye Models, a Review on Human Vision Applications and Perspectives for Use in Industry

“…Table 3 organizes the main modalities of the respective devices mentioned in this review. Some devices are “multi-modal”, and more than one measurement modality was reported in the respective publications [ 28 , 35 , 37 , 41 , 42 , 48 , 52 , 55 , 64 , 70 , 72 , 80 ].…”

“…The only physical model found to evaluate optical coherence tomography (OCT) measurements was described by Wang et al [ 72 ], which developed a tool for retinal OCT instrument calibration. The model comprised a doublet lens, a single filament, a piece of glass plate and a microsphere-embedded phantom.…”

“…Other corneal shapes have also been reported by several authors [ 16 , 27 , 31 , 54 , 56 ], who have used double-convex (biconvex) lenses. Single surface lenses have also been used, with convex-plano lenses being very common [ 15 , 29 , 33 , 34 , 35 , 40 , 63 , 64 , 72 , 85 ], due to the fact that the human posterior cornea has a relatively small contribution to the overall performance, essentially due to the small difference in refractive index between the aqueous fluid and the cornea, and the difficulty in replicating the posterior cornea [ 64 ]. The anterior radius in these cases is usually larger, and quite different values have been used, with extremes ranging from 7.75 mm to 24.224 mm having been found.…”

“…Some artificial models have used a lens to simulate the retina instead of a diffuser [ 35 , 72 ]. The light would be reflected on the posterior surface of the lens, in a similar way as a diffuser.…”

“…The light would be reflected on the posterior surface of the lens, in a similar way as a diffuser. The lens used by [ 72 ] was also marked on the rear surface with concentric circles to measure the angular field-of-view (FOV). A reflection lens for double-pass experiments was used in [ 35 ].…”