Intraocular lens short wavelength light filtering.

There is increasing interest in the effects of reactive oxygen species ('free radicals') in ageing, both in the body overall and specifically in the eye. Cataract and age-related macular degeneration (AMD) are two major causes of blindness, with cataract accounting for 48 per cent of world blindness and AMD accounting for 8.7 per cent. Both cataract and AMD affect an older population (over 50 years of age) and while cataract is largely treatable provided resources are available, AMD is a common cause of untreatable, progressive visual loss. There is evidence that AMD is linked to exposure to short wavelength electromagnetic radiation, which includes ultraviolet, blue and violet wavelengths. The ageing crystalline lens provides some protection to the posterior pole because, as it yellows with age, its spectral absorption increasingly blocks the shorter wavelengths of light. Ultraviolet blocking intraocular lenses (IOLs) have been the standard of care for many years but a more recent trend is to include blue-blocking filters based on theoretical benefits. As these filters absorb part of the visible spectrum, they may affect visual function. This review looks at the risks and the benefits of filtering out short wavelength light in pseudophakic patients.