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Straylight in the human eye: testing objectivity and optical character of the psychophysical measurement
Author(s) -
Van Den Berg Thomas J. T. P.,
Franssen Luuk,
Coppens Joris E.
Publication year - 2009
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.2009.00638.x
Subject(s) - human eye , optics , psychophysics , point spread function , light scattering , computer science , physics , scattering , psychology , neuroscience , perception
The point spread function or PSF of the human eye encompasses hugely different domains: a small‐angle, high‐intensity domain, called the ‘PSF core’, and a large‐angle, low‐intensity domain, usually referred to as ‘straylight’. The first domain can be assessed by available double‐pass or other optical techniques. For the second domain psychophysical techniques have been developed, in particular the Compensation Comparison or CC technique, recently made available for clinical application in the C‐Quant instrument. We address the question of whether the psychophysical technique gives measures of straylight that are compatible with those made by optical methods. With a small adaptation the CC method can be used to assess straylight from physical light scattering samples, instead of straylight in the eye, using the same psychophysics, but without interference from the ocular straylight. The light scattered by each of seven light‐scattering samples, encompassing the range of straylight values observed in human eyes, was measured by two optical methods and by the psychophysical technique. The results showed that the optical and psychophysical measurements for the seven samples were almost identical.