Whether you think you can, or think you can't.you are right! dHenry Ford Presbyopia is primarily an inevitable, age-related condition that causes irreversible loss of the accommo-dative amplitude of the eye. Despite its ubiquity, the exact mechanism behind presbyopia remains unclear. Worldwide in 2005, more than 1.04 billion people were estimated to have presbyopia. 1 By the year 2020, the worldwide prevalence is expected to rise to 1.37 billion. 1 The underlying cause for this age-related loss of accommodation has yet to be fully elucidated and continues to remain a topic of controversy. Models for presbyopia are broadly divided into 2 areas and are referred to as lenticular mechanisms and extralenticu-lar mechanisms. 2 Although the lenticular theories pro-pose age-related changes to the lens, capsule, and zonular fibers, the extralenticular mechanism includes ciliary muscle dysfunction, loss of elasticity in the pos-terior zonular fibers, and even decreased resistance on the vitreous against the lens capsule. 3,4 Presbyopia affects the quality of life. McDonnell et al. 5 showed that presbyopia was associated with substantial negative effects on health-related quality of life in a population study based in the United States. The safest and least invasive method to treat presby-opia consists of corrective glasses as a separate pair of reading glasses, bifocals, or progressive lenses. Several options to treat presbyopia have been pursued; these include monovision with contact lenses or with laser vision correction, multifocal ablation patterns on the cornea (termed presbyLASIK 6), and lenticular ap-proaches with refractive lens exchange with multifocal or extended depth of focus intraocular lenses. One of the earliest approaches for presbyopia correction was additive refractive keratoplasty, in which a foreign material, either biological or synthetic, is added to the corneal tissue to alter the refractive sta-tus. 7 Synthetic corneal inlays have been investigated for well over half a century. Barraquer was the first to use them in 1949 8 for the treatment of aphakia and myopia. The materials used for the synthetic inlays have improved from the early use of flint glass or poly(methyl methacrylate) to hydrogel polymers. The older generation of inlays led to several complica-tions, which included corneal opacification, 9 epithelial and stromal thinning, 10 intracorneal deposits, 11 and decentration.
Srinivasan, S. (2016, July 1). Corneal inlays for spectacle independence: Friend or foe? Journal of Cataract and Refractive Surgery, 42(7), 953–954. https://doi.org/10.1016/j.jcrs.2016.06.020