Keeping sight when the eyes age
Fading eyesight is a natural consequence of ageing. Presbyopia is a particular ocular condition that can affect everyone after the age of 45, hampering the ability to focus and leading to cataracts (the clouding of the eye lens) later in life.
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Optical aids to perform visual tasks exist, but they are far away from the ideal treatment which should rely on the restoration of the dynamic and continuous focusing ability of the eye. However, new innovative solutions to cure presbyopia are now emerging thanks to an EU-funded research project that is developing multifocal corrections and accommodating lenses.
The project, called PRESBYOPIA, is researching non-invasive techniques to study the eye’s structural properties and better understand the visual mechanics of its crystalline lens. The goal is to cure the condition by developing bio-inspired intraocular lenses that can mimic the dynamic and continuous focusing ability of the eye. These replacement lenses would thus have to be flexible and sophisticated enough to mimic the structure of the crystalline lens of a young eye.
The project team includes physicists, visual scientists, material and biomechanical engineers, examining the eye’s ability to change its shape to focus on near and distant objects and elucidating the mechanisms driving presbyopia, including the loss of elasticity of the crystalline lens.
“Novel high resolution and high speed 3D imaging technologies are allowing us to investigate the physical properties of the crystalline lens and to understand how they change with aging,” says PRESBYOPIA’s Principal Investigator, ERC Advanced Grantee, Prof. Susana Marcos, director at the Spanish National Research Council’s Institute of Optics in Madrid (Consejo Superior de Investigaciones Científicas, Instituto de Óptica).
The crystalline lens is about 4mm thick and 10mm in diameter, and extremely complex, able to increase its optical power and reduce light losses caused by reflection from its surface. The only current treatment available for cataracts is to surgically remove the lens and replace it with an intraocular lens implant.
The PRESBYOPIA project has designed and developed new multifocal and accommodative intraocular lenses, currently being tested using experimental simulations that provide the patient with a multifocal vision experience. These experiments are allowing the researchers to look for the optimal optical lens designs, and to understand the role of ocular optics and neural adaptation on visual perception with these lenses.
“We have also developed an innovative accommodative lens concept, which we have just recently sent to the Munich-based European Patent Office. We now face the challenge of testing this lens,” explains Marcos.
The project has already licensed the patent for one of the multifocal lens designs to a European company, and filed two other patents on accommodative lens design and instrumentation for screening candidates for multifocal intraocular lenses. With estimated revenues for the intraocular lens market of $3.1 billion worldwide, the PRESBYOPIA project fills a clear niche in this fast-growing market.