Non-Invasive Bleaching of the Human Lens by Femtosecond Laser Photolysis

Line Kessel,Mike Van Der Poel,Lars Eskildsen,Michael Larsen,Anna Mitraki

doi:10.1371/journal.pone.0009711

Line Kessel, Mike Van Der Poel + Show 3 more

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https://doi.org/10.1371/journal.pone.0009711

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Abstract

BackgroundGlobally, cataract is the leading cause of blindness and impaired vision. Cataract surgery is an attractive treatment option but it remains unavailable in sufficient quantity for the vast majority of the world population living in areas without access to specialized health care. Reducing blindness from cataract requires solutions that can be applied outside operating theatres. Cataract is a protein conformational disease characterized by accumulation of light absorbing, fluorescent and scattering protein aggregates. The aim of the study was to investigate whether these compounds were susceptible to photobleaching by a non-invasive procedure and whether this would lead to optical rejuvenation of the lens.Methodology/Principal FindingsNine human donor lenses were treated with an 800 nm infra-red femtosecond pulsed laser in a treatment zone measuring 1×1×0.52 mm. After laser treatment the age-induced yellow discoloration of the lens was markedly reduced and the transmission of light was increased corresponding to an optical rejuvenation of 3 to 7 years.Conclusions/SignificanceThe results demonstrate that the age-induced yellowing of the human lens can be bleached by a non-invasive procedure based on femtosecond laser photolysis. Cataract is a disease associated with old age. At the current technological stage, lens aging is delayed but with a treatment covering the entire lens volume complete optical rejuvenation is expected. Thus, femtosecond photolysis has the potential clinical value of replacing invasive cataract surgery by a non-invasive treatment modality that can be placed in mobile units, thus breaking down many of the barriers impeding access to treatment in remote and poor regions of the world.

Highlights

Cataract is the world-leading cause of blindness and visual impairment accountable for almost 20 million cases of bilateral blindness [1]
Conclusions/Significance: The results demonstrate that the age-induced yellowing of the human lens can be bleached by a non-invasive procedure based on femtosecond laser photolysis
With time the structural lens proteins are subjected to posttranslational modifications by non-enzymatic glycation [9] and other biochemical and biophysical pathways [3] leading to an accumulation of chromophores that absorb visible light preferentially in the blue end of the spectrum [10], giving the aged human lens its characteristic yellow-brown color

Summary

Introduction

Cataract is the world-leading cause of blindness and visual impairment accountable for almost 20 million cases of bilateral blindness [1]. Blindness from cataract could be prevented if only high quality and high volume cataract surgery was available all over the globe [2] This is not the case and the barriers impeding access to treatment includes lack of skilled and well-trained surgeons, lack of sterile operating facilities, lack of the high-tech equipment required for the surgical procedure, and the high cost of the procedure rendering the surgery inaccessible to a vast majority of world population. With time the structural lens proteins are subjected to posttranslational modifications by non-enzymatic glycation [9] and other biochemical and biophysical pathways [3] leading to an accumulation of chromophores that absorb visible light preferentially in the blue end of the spectrum [10], giving the aged human lens its characteristic yellow-brown color. The aim of the study was to investigate whether these compounds were susceptible to photobleaching by a non-invasive procedure and whether this would lead to optical rejuvenation of the lens

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