Carbon Black Tinted Contact Lenses for Reduction of Photophobia in Cystinosis Patients

ABSTRACTPurpose: To examine if current development on using contact lenses for drug delivery of cysteamine to treat ocular symptoms of cystinosis can be tinted to mitigate photophobia common in patients by reducing transmittanceMethods: Commercial contact lenses were placed in a carbon black solution to examine loading after lens synthesis. Silicone hydrogel contact lenses were also synthesized with carbon black added prior to UV curing. Transmittance was measured using UV–vis spectrophotometry over the range of 190–1190 nm and compared to unmodified contact lenses. Lens parameters of refractive index, ion permeability, and Young’s modulus were measured using a refractometer, release of sodium chloride, and the cantilever method. Cysteamine release was measured by loading lenses into 5% cysteamine solution and then monitoring the release of the drug using UV–vis spectrophotometry. Vitamin E diffusion barriers were also added to lenses via ethanol solution, and the release of cysteamine from these modified...