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Optical characterization of PCO
Author(s) -
VAN DEN BERG TJTP,
VAN BREE MCJ
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.1755-3768.2010.4241.x
Subject(s) - optics , monochromatic color , wavelength , cornea , light scattering , contrast (vision) , posterior capsule opacification , materials science , ophthalmology , physics , scattering , visual acuity , medicine , phacoemulsification
Purpose Opacification of the posterior capsule (PCO) is known to degrade visual function on both counts: small angle resolution (visual acuity and contrast sensitivity) as well as large angle light scatter (straylight). No studies have been performed to delineate the optical characteristics of PCO as a basis for explanation of these visual function defects. Methods Preparations of IOL‐capsule combinations were harvested from donor eyes after removal of the cornea. They were mounted submersed in saline in an optical set‐up, used earlier to characterize the optics of the crystalline lens (van den Berg et al. VR 1999). Illuminated by monochromatic beams of light, the light spreading originating from different areas of the preparation was measured as function of wavelength for different angles. Based on physical optics theory, the optical characteristics of PCO was derived. The data will be presented translated into the straylight parameter, directly comparable to the figures obtained in vivo using the clinical straylight meter (C‐Quant from Oculus). Results Twenty successful preparations were harvested with at least some PCO areas. PCO grades varied from severe to slight. Two physically different types of light spreading could be discriminated. One type corresponding to pearl‐like appearance, characterized by little wavelenght dependence and smal angle dominance. The other type corresponding to diffuse scatter, characterized by strong wavelength dependence and large angle dominance. The scatter values measured corresponded to clinical measures of straylight in PCO patients using the C‐Quant. Conclusion The light scattering characteristics of PCO show two types of optical disturbance: a refractile type, probably dominated by pearl‐like structures, and a diffuse type of scattering of yet unclear origin.