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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

Transmission changes after laser irradiation at 420 nm.The graph demonstrates the changes in transmission measured after irradiation by a 420 nm cw laser for a 68 year old human lens. From a baseline transmission that was lower than a 46-year old non-irradiated reference lens throughout the spectrum, transmission gradually increases to approach that of the younger reference lens after a dose of 1440 J/cm2.
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pone.0123732.g001: Transmission changes after laser irradiation at 420 nm.The graph demonstrates the changes in transmission measured after irradiation by a 420 nm cw laser for a 68 year old human lens. From a baseline transmission that was lower than a 46-year old non-irradiated reference lens throughout the spectrum, transmission gradually increases to approach that of the younger reference lens after a dose of 1440 J/cm2.

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)

Transmission changes after laser irradiation at 420 nm.The graph demonstrates the changes in transmission measured after irradiation by a 420 nm cw laser for a 68 year old human lens. From a baseline transmission that was lower than a 46-year old non-irradiated reference lens throughout the spectrum, transmission gradually increases to approach that of the younger reference lens after a dose of 1440 J/cm2.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0123732.g001: Transmission changes after laser irradiation at 420 nm.The graph demonstrates the changes in transmission measured after irradiation by a 420 nm cw laser for a 68 year old human lens. From a baseline transmission that was lower than a 46-year old non-irradiated reference lens throughout the spectrum, transmission gradually increases to approach that of the younger reference lens after a dose of 1440 J/cm2.
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