The spectral sensitivity of the human eye depends upon the sensitivity of the retinal elements. However, in the intact human eye the composition of the radiant energy reaching the retina is such that its sensitivity in the violet and near ultraviolet can not be evaluated fully by psychophysical methods. Owing to the absorption of the near ultraviolet by the yellow crystalline lens, which has a rather sharp cut-off at 400 mμ, ultraviolet radiation generally reaches the retina only in minimal quantities.
In one of his most remarkable papers. Wald1 has shown, among other things, that with the removal of the lens the eye gains enormously in sensitivity in the violet and ultraviolet. Whereas in the intact human eye the sensitivity of the fovea declines at 365 mμ to 1/40,000 of its maximal value at 562 mμ, aphakic rod-and-cone vision is still about 1/30 as sensitive at 365 mμ as
BURIAN HM, ZIV B. Electric Response of the Phakic and Aphakic Human Eye to Stimulation with Near Ultraviolet. AMA Arch Ophthalmol. 1959;61(3):347-350. doi:10.1001/archopht.1959.00940090349001