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Comparison of the two domains of visual optics: the aberrometric domain and the straylight domain
Author(s) -
VAN DEN BERG TJTP,
FRANSSEN L,
COPPENS JE
Publication year - 2010
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2010.4432.x
Subject(s) - optics , point spread function , spherical aberration , physics , contrast (vision) , lens (geology)
Purpose The ocular point‐spread‐function defines the functional problem originating from optical defects in the eye. Aberrations as well as scatter degrade the psf. How do these two types of defect differ with respect to their effect on the psf, and on functional measures? Methods Literature models for different aspects of the optical irregularities in the eye media, in particular Thibos et al. JOSA A 2002 for the aberration structure and Van den Berg et al. VR 1999 for small particle scattering, were used to delineate their effects on the psf. The Thibos et al. model was extrapolated to allow inclusion of the high orders of aberration not normally included in aberrometry, but potentially visible with double pass. With respect to the visual function counterparts, straylight (C‐Quant from Oculus) outcomes were compared to visual acuity and contrast sensitivity in 2400 subjects. Results As a reference the full scale psf standard model of Vos et al. CIE 1999 was used. The modeled aberration structures of the eye proved to predict the central part of the psf up till about 0.3 degrees if extreme high orders were included. For angles >1 degree predicted values were far below the actual values of the psf. Small particle scattering was essential to predict the psf for angles above 1 degree. Conclusion In the assessment of disturbances to the optical media two domains must be discriminated: the aberration domain and the small particle domain, with corresponding parts (small angle vs large angle) to the psf. Straylight typically originates from irregularities of size 10 micrometer and below, as opposed to aberrations originating from refractile humps and bumps extending over 100 micrometer and more. Straylight has independent value.