IOL filters, is there an optimal absorption?

Purpose To analyze the need for optical filtering in IOLs Methods The spectral distribution of radiation from the sun, the action spectra for diurnal rhythm regulation and vision, and the action spectra for phototoxic effects in the aphacic and pseudophacic eye were analyzed. Results Ultraviolet radiation (UVR), visible radiation and infrared radiation from the sun reaches the surface of the earth. In the aphacic eye, the retina is exposed to considerable amounts of toxic optical radiation. At the same time, optical radiation is required for vision and diurnal rhythm regulation. Therefore, an IOL needs to block toxic radiation while conserving enough light for vision and diurnal rhythm regulation. The cornea blocks out UVR below 290 nm and then gradually transmits more toward longer wavelengths. The aqueous humor and the vitreous provide some additional blocking of UVR up to 320 nm but then transmits large amounts of longer wavelength radiation up to 1400 nm. In the phacic eye, the crystalline lens, age dependently, blocks out UVR and short wavelength visible radiation. Diurnal rhythm is regulated by melatonin and the action spectrum for the regulation has a maximum around 450 nm. Scotopic vision has a maximum sensitivity around 505 nm and photopic vision around 555 nm. UVR is increasingly toxic towards shorter wavelengths. Visible light causes a retinal Type I phototoxicity with a maximum action around 505 nm and a Type II phototoxicity with a maximum action around 440 nm. Conclusion It is possible and desirable to block the UVR hazard and the Type II phototoxic reaction with conserved diurnal rhythm regulation and scotopic and photopic vision with IOLs.