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

Increasingyellow colorof lens with increasingage

Nuclearcataractin 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 430-490 nmFluorometry

Fluorescence 530-630 nm

The lens is naturally fluorescent in blue light

(blue-blocking filter)

Beer is fluorescent, like the lens,because ofglycation

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 residentesde 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. 2009 Mar 2