Refractive index adjustable intraocular lens design to achieve diopter control for improving the treatment of ametropia after cataract surgery

Intraocular lens (IOL) implantation is currently the most effective clinical treatment for cataracts. Nevertheless, due to the growth of the eye axis in patients with congenital cataracts during the process of growth and development, the progressive incapacity of an IOL with a fixed focus does not meet the demands of practical usage, leading to the occurrence of ametropia. This work describes an innovative class of an IOL bulk material that offers good biosafety and light-controlled refractive index adjustment. Acrylate materials were synthesized for the preparation of IOLs by free radical polymerization of ethylene glycol phenyl ether methacrylate (EGPEMA), hydrophilic monomer 2-(2-ethoxyethoxy) ethyl acrylate (EA), and functional monomer hydroxymethyl coumarin methacrylate (CMA). Under 365/254 nm ultraviolet (UV) irradiation, the coumarin group could adjust the polymer material's refractive index through reversible photoinduced dimerization/depolymerization. Meanwhile, the potential for the IOL use is enabled by its satisfactory biosafety. Such a light-induced diopter adjustable IOL will be more appropriate for implantation during cataract surgery since it will not require the correction needed for ametropia and will offer more accurate and humane treatment. A coumarin group containing-copolymer was synthesized and fabricated into intraocular lenses (IOL). A functional IOL is diopter adjustable by light irradiation through triggering the [2 + 2] cycloaddition of the coumarin groups. Such light-triggered diopter-adjustable copolymer IOLs have a great potential in clinical application.