Intense Spectral Light Effects on Spectral Sensitivity

The spectral sensitivity of rhesus monkeys has been accounted for as the upper envelope of three response channels, the sensitivities of two of which are determined by inhibitory interaction between the responses of the two classes of cones with 535 and 575 nm absorption peaks [1]. When the eye is exposed for long periods to a high intensity of a spectral waveband which is more strongly absorbed by one class of cones, there is a long-term, perhaps permanent, change in spectral sensitivity as measured by psychophysical techniques. Exposure to 10 m 4 w/steradian at the cornea of a 6 nm band centred on 463 nm for 1·5 hours per day for seven consecutive days produced greater than 90 per cent loss of sensitivity over the blue region, which has not recovered in 14 months. The loss closely coincides with the region of the class of cones with 445 nm peak absorption. Exposure for a similar period to 10 m 3 w/steradian at the cornea of a 6 nm waveband centred on 520 nm produced some loss of sensitivity throughout t...