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A simple and effective video keratometric system.

H Igarashi·M Kojima·S Igarashi·A Yoshida·H M Cheng
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Abstract

We tested a personal computer-based video keratometric system used to analyze projected placido disk rings. The system consists of a Maloney surgical keratometer that projects the rings and a video camera attached to an operating microscope. Images of the rings were transmitted to a video image processing board and analyzed on a personal computer using an analysis program we developed. System precision was evaluated in 18 eyes. The values were compared with those obtained using a commercial photokeratometer (control). In all eyes, the principal meridian values differed from the controls by < 0.04 mm. In 15 eyes (83%), the measurements were within 0.03 mm of the controls. The corneal astigmatism values and cylindrical axes were within 0.12 diopters in 17 eyes (94%) and within 5 degrees in all cases, respectively. Our system, which can analyze placido disc rings projected from other systems, is sufficiently precise to measure the corneal radius of curvature and astigmatism.

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CalibrationCorneaHumansImage Processing, Computer-AssistedRegression AnalysisSoftwareTelevisionJournal Article

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H Igarashi, M Kojima, S Igarashi, A Yoshida, H M Cheng. 1995. A simple and effective video keratometric system.. https://doi.org/10.1111/j.1600-0420.1995.tb00038.x

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