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Conventional means of sight
correction, like glasses or contact lenses, deal with the global
parameters of eye refraction. Modern laser technologies which enable
point by point cornea reshaping, require accurate local parameter
information for achieving higher sight acuity. TRACEY1, being developed
by one of our clients (Tracey Technologies, Houston, TX) is a single
beam refractometer based on retina ray tracing for measuring eye
refraction distribution.
The figure above summarizes the basic technique of retina ray tracing.
A laser beam is scanned parallel to the eye axis and the deviation
of the spot image from the ideal position is recorded with an optical
position detector. Ray tracing algorithms are then used to back
calculate a refractive index map of the eye.
A first generation prototype of TRACEY-1 was developed by researchers
at the Institute for Biomedical Engineering in Kiev, Ukraine. Indus
designed all the electronics and the control firmware for the second
generation system, now being manufactured and marketed as the Visual
Function Analyzer by Tracey
Technologies (Houston, Tx).
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