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Action spectrum for photobleaching of human lenses by short wavelength visible irradiation.

Kessel L, Larsen M - PLoS ONE (2015)

Bottom Line: For a 75 year old lens an effect corresponding to elimination of 15 years or more of optical ageing was obtained.This study of the spectral characteristics and intensity needed to bleach the human lens with single-photon laser effects found an action-spectrum peak at 420 nm tailing gradually off toward longer wavelengths and more steeply toward shorter wavelengths.The results may be used to guide experiments with two-photon bleaching.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.

ABSTRACT

Purpose: Cataract is the world-leading cause of blindness. In search for a new treatment of cataract we have found that the yellow discolouration of aged human lenses can be photobleached using a non-invasive, infra-red, femtosecond laser treatment. These results were presented in an earlier PlosOne publication. The objective of the study was to characterize the single-photon photobleaching action spectrum of the aged human lens in vitro.

Methods: Ninety-one human donor lenses were irradiated with continuous wave laser light at 375, 405, 420, 445, 457 or 473 nm. Photobleaching was monitored by photography and transmission measurements.

Results: The action spectrum peaked at 420 nm followed by, in order of decreasing effect, 445, 457, 473, 405 and 375 nm. Younger and less absorbent lenses showed smaller changes than older and more absorbent lenses. There was a dose-dependent increase in lens transmission with increasing laser irradiation.

Conclusions: For a 75 year old lens an effect corresponding to elimination of 15 years or more of optical ageing was obtained. This study of the spectral characteristics and intensity needed to bleach the human lens with single-photon laser effects found an action-spectrum peak at 420 nm tailing gradually off toward longer wavelengths and more steeply toward shorter wavelengths. The results may be used to guide experiments with two-photon bleaching.

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Related in: MedlinePlus

Comparison of blue light transmission before and after laser irradiation.The graph shows the transmission of blue light (450–490 nm) before (x-axis) and after (y-axis) laser irradiation at 375 nm (△), 405 nm (○), 420 nm (■), 445 nm (▲), 457 nm (×) and 473 nm (♦) for all 91 lenses included in the experiments.
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pone.0123732.g002: Comparison of blue light transmission before and after laser irradiation.The graph shows the transmission of blue light (450–490 nm) before (x-axis) and after (y-axis) laser irradiation at 375 nm (△), 405 nm (○), 420 nm (■), 445 nm (▲), 457 nm (×) and 473 nm (♦) for all 91 lenses included in the experiments.

Mentions: Laser exposure was followed by improved transmission over nearly the entire width of the visible spectrum, see Fig 1. In the blue light region (450–490 nm), where age-related transmission loss is most prominent, transmission increased after exposure in all lenses. On average transmission increased by 26% and 53 lenses (58%) showed a transmission increase >20%. In 11 lenses (12%) the transmission increase was <5%, see Fig 2.


Action spectrum for photobleaching of human lenses by short wavelength visible irradiation.

Kessel L, Larsen M - PLoS ONE (2015)

Comparison of blue light transmission before and after laser irradiation.The graph shows the transmission of blue light (450–490 nm) before (x-axis) and after (y-axis) laser irradiation at 375 nm (△), 405 nm (○), 420 nm (■), 445 nm (▲), 457 nm (×) and 473 nm (♦) for all 91 lenses included in the experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401553&req=5

pone.0123732.g002: Comparison of blue light transmission before and after laser irradiation.The graph shows the transmission of blue light (450–490 nm) before (x-axis) and after (y-axis) laser irradiation at 375 nm (△), 405 nm (○), 420 nm (■), 445 nm (▲), 457 nm (×) and 473 nm (♦) for all 91 lenses included in the experiments.
Mentions: Laser exposure was followed by improved transmission over nearly the entire width of the visible spectrum, see Fig 1. In the blue light region (450–490 nm), where age-related transmission loss is most prominent, transmission increased after exposure in all lenses. On average transmission increased by 26% and 53 lenses (58%) showed a transmission increase >20%. In 11 lenses (12%) the transmission increase was <5%, see Fig 2.

Bottom Line: For a 75 year old lens an effect corresponding to elimination of 15 years or more of optical ageing was obtained.This study of the spectral characteristics and intensity needed to bleach the human lens with single-photon laser effects found an action-spectrum peak at 420 nm tailing gradually off toward longer wavelengths and more steeply toward shorter wavelengths.The results may be used to guide experiments with two-photon bleaching.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.

ABSTRACT

Purpose: Cataract is the world-leading cause of blindness. In search for a new treatment of cataract we have found that the yellow discolouration of aged human lenses can be photobleached using a non-invasive, infra-red, femtosecond laser treatment. These results were presented in an earlier PlosOne publication. The objective of the study was to characterize the single-photon photobleaching action spectrum of the aged human lens in vitro.

Methods: Ninety-one human donor lenses were irradiated with continuous wave laser light at 375, 405, 420, 445, 457 or 473 nm. Photobleaching was monitored by photography and transmission measurements.

Results: The action spectrum peaked at 420 nm followed by, in order of decreasing effect, 445, 457, 473, 405 and 375 nm. Younger and less absorbent lenses showed smaller changes than older and more absorbent lenses. There was a dose-dependent increase in lens transmission with increasing laser irradiation.

Conclusions: For a 75 year old lens an effect corresponding to elimination of 15 years or more of optical ageing was obtained. This study of the spectral characteristics and intensity needed to bleach the human lens with single-photon laser effects found an action-spectrum peak at 420 nm tailing gradually off toward longer wavelengths and more steeply toward shorter wavelengths. The results may be used to guide experiments with two-photon bleaching.

Show MeSH
Related in: MedlinePlus