S-cone sensitivity in unilateral aphakia
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G L Savage1, G Haegerstrom-Portnoy
1College of Optometry, University of Houston, Texas.
Background:
Exposure to ultraviolet radiation (UVR) and blue light has been shown to cause retinal damage in animals. In humans, it has been argued that the loss of short-wavelength (S) cone sensitivity during normal aging may be related to chronic light exposure.
Methods:
We measured sensitivity to blue and yellow lights presented on bright yellow backgrounds at several retinal eccentricities in both eyes of an observer with long-standing unilateral aphakia.
Results:
For yellow lights, where media absorption is not a major factor, there was a 2-fold loss in sensitivity of long (L) and medium (M) wavelength cone mechanisms in the aphakic eye relative to the phakic eye. For blue lights detected by S-cones, there was a 10-fold loss of S-cone mechanism sensitivity in the aphakic eye, after differences in ocular media density were taken into account.
Conclusions:
Our findings strongly support the hypothesis that chronic exposure to short wavelength radiation impairs S-cone function.