Calibration Issues In The Measurement Of Ocular Movement And Position Using Computer Image Processing


There has been a desire for some time by practitioners and researchers in the ophthalmology field for an instrument to automatically measure eye alignment quickly and accurately. With MS DOS based Personal Computer image processing systems becoming readily available and inexpensive, a method is presented that uses image processing tools to easily diagnose eye misalignment and initiate the appropriate treatment. The MS DOS based Personal Computer image processing system discussed is able to accurately measure the monocular inner pupillary distance, compute the axial length of each eye, and measure angular deviations so that tropias and phorias can easily be measured. Calibration of the imaging system requires that the pixel displacement as a function of eye movement be known. It is the purpose of this paper to present experimental data collected over several patients with and without strabismus (ocular deviations) and a detailed theoretical analysis that calibrates the imaging system discussed. In designing the imaging system to measure ocular deviations, several calibration schemes were developed. The first uses estimated data collected and published in the literature on the axial length of the eye as a function of the patient's eye (Estimated), the second uses the axial length of the eye measured from an A-scan (Calibrated), and the third uses the imaging system directly to compute the axial length (Physiologic).

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Proceedings of SPIE - The International Society for Optical Engineering



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Article; Proceedings Paper



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85075896806 (Scopus)

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