Age-related yellowing and fluorescence of the lens: Effect of ultraviolet radiation? Line Kessel, 1 Peter Kristian Kofoed, 1 Gustavo Zubieta-Calleja 2 Michael Larsen 1,3 1 Department of Ophthalmology, Copenhagen University Hospital Glostrup, Denmark 2 Instituto de Patologia de la Altura (Clinica IPPA), High Altitude Pathology Institute, La Paz, Bolivia 3 Kennedy Centre, National Eye Clinic, Copenhagen, Denmark
Mechanism of accomodation: contraction of ciliary muscle (3), relaxation of zonular fibers, assumption of more globular shape of lens (4). Presbyopia and stiffness of lens related to yellowing? – Not known
Increasing yellow color of lens with increasing age
Nuclear cataract in optical cross-section
”Chemical rays””Heat rays” Short wavelength = higher likelyhood of inducing chemical reaction Examples: Vision Photoprotection (carotenoids, melanin) Vitamin D synthesis Bilirubin elimination Photodynamic therapy
Excitation nm Fluorometry Fluorescence nm The lens is naturally fluorescent in blue light
(blue-blocking filter) Beer is fluorescent, like the lens, because of glycation
Background: 1. Lens fluorescence increases with age 2. The rate is increased by diabetes 3. Glucose reacts with protein to produce yellow and fluorescent non-enzymatic glycation products 4. Yellowing of purified lens protein can be induced by ultraviolet radiation
Hipotesis: Do ultraviolet promote the accumulation of fluorophores in the lens? Method: Comparison of age-matched Bolivian highlanders and Danish lowlanders using non-invasive lens fluorometry
Results:
End
Conclusion: Este estudio comparativo entre Bolivianos residentes de la altura 3600 m durante toda su vida y Daneses residentes a nivel del mar, no dio evidencia de una aceleración del envejecimiento del cristalino. Estos resultados demuestran que los diferentes niveles de radiación ultravioleta no juegan un rol en el envejecimiento del cristalino.
Lens autofluorescence is not increased at high altitude. Kessel L, Kofoed PK, Zubieta-Calleja G, Larsen M. Acta Ophthalmol Mar 2