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Guoqiang Li, Jinan Xia; Large-Aperture Adaptive Liquid Crystal Lens for Correction of Presbyopia. Invest. Ophthalmol. Vis. Sci. 201657(12):.
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© ARVO (1962-2015); The Authors (2016-present)
Presbyopia is a symptom with difficulty in near-vision tasks due to aging. Bifocal, trifocal, and progressive lenses have been widely used for the treatment. However, these lenses have limited field of view or severe distortion and may cause discomfort or dizziness to the subjects when they use different parts of the lens for different vision tasks. It is estimated that more than 42% of the adults in US are presbyopic and the number is increasing. Switchable electro-optic liquid crystal (LC) lenses offer a revolutionary solution to this vital vision care problem by overcoming the above mentioned shortcomings. However, to achieve LC lenses with a large aperture and high optical quality is very challenging.
The conventional refractive LC lenses cannot achieve the aperture and power needed for spectacle lenses for correction of presbyopia. Diffractive LC lenses allow larger aperture, high-efficiency (near 90%), low driving voltage (a few volts), and low power dissipation. The phase modulation is achieved by applying voltages to the patterned ring electrodes. We proposed a new design concept - harmonic diffractive LC lens to achieve the goal. The phase modulation of the harmonic diffractive lens in each zone is multiples of 2π radians. By considering the effective refractive index change of the LC materials and the response time, we chose 10π radians for the total phase change in each zone.
Lenses with an aperture of 20-30 mm and various base powers of 1.0-3.5 diopters have been designed. These specifications are needed for practical clinical application. All the lenses that cannot be achieved based on the conventional diffractive LC lens concept can be accomplished based on the harmonic diffractive lens. By changing the slope of the applied voltage, both positive and negative powers can be realized. The chromatic aberration is greatly reduced as the lens can focus multiple wavelengths constructively. Furthermore, the lens is relatively thin (about 11 µm) and hence the response is fast. Experimental results will be reported. Clinical tests demonstrate the effectiveness of the new lens for correction of presbyopia.
By using harmonic diffractive lens concept, switchable lenses with 20-30 mm aperture and 1.0-3.5 diopters power can be achieved. These lenses are promising for correction of presbyopia and this represents a significant advance in this field.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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