Spectral transmission of intraocular lenses expressed as a virtual age
- ProfessorDr D van Norren, University Medical Center Utrecht, Department of Ophthalmology AZU E03.136, PO Box 85500, NL-3508 GA, Utrecht, the Netherlands;
- Received 27 February 2007
- Revised 22 March 2007
- Accepted 3 April 2007
Aim: Currently available intraocular lenses (IOL) have widely different spectral filters. This study aimed to calculate the virtual age of IOL with regard to photoprotection and photoreception, i.e. the age of the natural lens that has similar effects on these aspects.
Methods: With diffuse solar radiation as a light source blue light damage was calculated for natural lenses at all ages, commercially available IOL and Schott steep cut-off filters in the wavelength range 300–600 nm. Similarly, the input to the short wavelength sensitive cone system was calculated for the range 380–600 nm.
Results: The virtual age for photoprotection of IOL and steep cut-off filters varied from under 0 to 66 years. Most IOL had similar ages for photoreception, and thus show a reasonable resemblance to the spectral properties of the natural lens. Two IOL and all steep cut-off filters had a lower age for photoreception than for photoprotection, and thus outperformed the natural lens.
Conclusion: The virtual age of an IOL relates its spectral filtering properties to what happens in the healthy crystalline lens. Many older IOL types offer less protection than the lens of a newborn. Middle age seems a reasonable choice for an IOL.
Competing interests: None declared.
short wavelength sensitive