S-cone sensitivity in unilateral aphakia.

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.