Abstract
Purpose: :
Yellow intraocular lenses (IOLs) capable of filtering short wavelength light do not impair visual functioning as evidenced by previous investigations. However, little attention has been given to the potential benefits of these implants. For example, glare disability and photostress have been shown to be improved by yellow intraocular filters (e.g., macular pigment). The current project tested glare disability and photostress in subjects with yellow implants, clear IOLs, or crystalline lens controls.
Methods: :
Subjects included 17 patients with yellow IOLs, 20 with clear IOLs, and 22 natural lens controls. Researchers remained blind to group assignment throughout the assessments. Photostress recovery and veiling glare experiments were conducted using a Maxwellian view optical system. Photostress recovery was defined as the time necessary to detect a 1°-diameter target comprised of a 100%, 5cpd grating following a 5-second exposure to a 5°-diameter disk comprised of broad-band xenon light. For the glare disability assessment, an annulus with a 10° inner and 12° outer diameter served as a the glare source. The intensity of the annulus was adjusted until the subject could no longer detect a 1°-diameter disk containing a 100%, 5cpd grating stimulus.
Results: :
Controls had the highest thresholds in the veiling glare assessment compared to subjects with yellow (p < 0.0001) and clear (p < 0.035) IOLs. Patients with yellow IOLs could withstand more light than patients with clear IOLs (p < 0.02). Subjects with yellow or clear implants did not differ in photostress recovery time (p < 0.32). Controls had significantly lower recovery times; however, the difference was less with respect to the yellow IOL group (p < 0.05) compared to the clear IOL group (p < 0.01).
Conclusions: :
Yellow IOLs have a benefit of reducing glare disability but do not significantly improve visual recovery following exposure to a bright light source. The absence of a significant effect on photostress recovery can be explained by the higher lens optical density of subjects with crystalline lenses and the short wavelength filtering properties of the yellow IOLs.
Keywords: intraocular lens • aging: visual performance