Straylight in the human eye: testing objectivity and optical character of the psychophysical measurement.
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.
Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands. t.j.vandenberg@nin.knaw.nl
Thomas J T P
TJ
van den Berg
Luuk
L
Franssen
Joris E
JE
Coppens
D015350:Contrast Sensitivity / Q000502:physiology; D006801:Humans; D008266:Macula Lutea / Q000528:radiation effects*; D055095:Optics and Photonics / Q000379:methods*; D011601:Psychophysics; D012029:Refraction, Ocular / Q000502:physiology; D012160:Retina / Q000528:radiation effects*; D012168:Retinal Pigments / Q000528:radiation effects*; D012542:Scattering, Radiation; D014785:Vision, Ocular / Q000502:physiology; D014794:Visual Fields / Q000502:physiology
D012168:Retinal Pigments