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Farah Shareef, David Szlachta, Genesis Contreras, Andrew Chen, Dimitri T Azar, Michael Cho; Designing a Photo-Responsive Contact Lens. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6102.
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© ARVO (1962-2015); The Authors (2016-present)
Excessive light exposure associated with diminished iris functionality leads to photophobia, glare, and poor vision in patients with congenital or trauma induced iris damage. Commercial artificial irises provide aesthetics by reconstructing the iris shape and color without restoring iris functionality. A new photo-responsive contact lens that mimics the natural iris’s dynamic response to light was developed using DEA, a photochromic material, within a biocompatible polymer matrix. Activated by blue light, DEA changes its opacity to reduce light transmission to the eye.
DEA powder dissolved in acetone was combined with polydimethylsiloxane (PDMS, Sylgard 184, Sigma) and underwent a 4-day wash cycle to form the photochromic contact lens. Optical properties including the kinetics of activation and reversal, and percent light attenuation were measured using a DU 530 UV/Vis Spectrophotometer for wavelengths 300-700nm. In vitro cell toxicity testing was conducted for up to 1 month. A live/dead viability assay and confocal microscope were used to stain and image the cells. Potential leaching of DEA from the contact lens was quantified by comparing wash cycle water to water with known amounts of DEA.
Photochromic contact lens were created with 0.025 to 0.4 weight percent DEA uniformly distributed in PDMS. Optical testing indicated reversible activation in 1 second. Wavelength scans showed graded attenuation of up to 40% of UV and visible light. Quantification of live cells demonstrated 90% cell viability with no significant change in morphology or proliferation rate between control cells and those exposed to our contact lens. Degradation studies revealed leaching of less than 0.5% DEA.
A novel design for our photochromic contact lens was achieved by integrating DEA within a PDMS polymer matrix. Rapid and reversible activation by blue light allows the contact lens to control light entering the eye and thus alleviate the adverse symptoms of decreased iris function. Cell culture experimentation demonstrated biocompatibility. Subsequent testing showed minimal DEA leaching, which corroborated these findings. By mimicking the natural iris functionality, our photochromic contact lens may provide an improved treatment option for patients with iris damage.
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