The GH-LCD electrodes can be partitioned in independent rings that mimic the functionality of the natural iris when actuated in the correct sequence. GH-LCD is composed by liquid crystal, chiral dopant and dichroic dye, and is capable of producing transmittance variations when an electric field is applied between its parallel electrodes, due to the combination of chirality and double absorption profiles of the mix 4. The artificial iris solution is based on the so-called guest–host liquid crystal (GH-LCD) 24, 25. Liquid crystal cells (LC) are particularly attractive as an active electro-optical component 20, 21 for presbyopia correction (the age-related loss of the ability to dynamically focus near and far objects) 22, 23 or a solution for iris defects (such as aniridia, the partial or complete absence of iris) 8. These applications can be attained thanks to important breakthroughs in miniaturized stretchable systems and hybrid integration of a variety of components onto flexible platforms 13, 14, 15, 16, 17, 18, 19. This work demonstrates the beneficial optical effects of an active artificial iris, based on visual simulations in response to different light levels, and enables further experimental investigation on patients to validate the dynamic light attenuation and visual performance of smart contact lenses with GH-LCD.Ī smart contact lens is a device with integrated electronics in direct contact with the eye, which provides sensing, actuation and wireless communication 1, 2 and offers both remarkable opportunities and challenges in a wide range of ocular applications: (1) active vision correction 3, 4, 5, 6, 7, 8, (2) biomedical sensing 9, 10, 11 and (3) augmented reality 5, 12. The visual modelling suggests a maximum depth-of-focus value for a 2-mm pupil diameter for both eyes as follows: 3D (1,000 cd/m 2), 2D (10 cd/m 2) and 0.75D (1 cd/m 2).
Visual simulations at different light conditions (high/low photopic and mesopic) demonstrated the theoretical capacity of the customized artificial iris smart contact lens to expand the depth-of-focus and decrease the optical aberrations (in particular, the spherical aberration). Experimental validation of the GH-LCD spectrum and iris contrast (determined to be 1:2.1) enabled the development of optical models that include the effect of a small pupil on image quality and visual quality on an optical system with aniridia characteristics. The artificial iris is based on guest–host liquid crystal cells (GH-LCD) in order to actively modify the transmittance of the lens and effective pupil size.
This paper presents the simulated performance assessment of an artificial iris embedded on a scleral contact lens using real data from an aniridia patient.
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