1 September 2004 Automated detection of ocular focus
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We characterize objectively the state of focus of the human eye, utilizing a bull's eye photodetector to detect the double-pass blur produced from a point source of light. A point fixation source of light illuminates the eye. Fundus-reflected light is focused by the optical system of the eye onto a bull's eye photodetector [consisting of an annulus (A) and a center (C) of approximately equal active area]. To generate focus curves, C/A is measured with a range of trial lenses in the light path. Three human eyes and a model eye are studied. In the model eye, the focus curve showed a sharp peak with a full width at half maximum (FWHM) of ±0.25 D. In human eyes, the ratio C/A was >4 at best focus in all cases, with a FWHM of ±1 D. The optical apparatus detects ocular focus (as opposed to refractive error) in real time. A device that can assess focus rapidly and objectively will make it possible to perform low-cost, mass screening for focusing problems such as may exist in children at risk for amblyopia.
© (2004) Society of Photo-Optical Instrumentation Engineers (SPIE)
David G. Hunter, David G. Hunter, Kevin J. Nusz, Kevin J. Nusz, Nainesh K. Gandhi, Nainesh K. Gandhi, Imran H. Quraishi, Imran H. Quraishi, Boris I. Gramatikov, Boris I. Gramatikov, David L. Guyton, David L. Guyton, } "Automated detection of ocular focus," Journal of Biomedical Optics 9(5), (1 September 2004). https://doi.org/10.1117/1.1781669 . Submission:

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