—Dr Josephson discusses potential limitations of simultaneous vision. We discussed these potential limitations, briefly reviewed the literature on multifocal lenses in our article,1 and recommended a conservative approach to the purposeful creation of multifocal corneas in humans. At present, there is no US Food and Drug Administration-approved protocol for doing this in the United States, but we are aware of some surgeons doing multifocal corrections in Europe.As with multifocal contact lenses and intraocular lenses, we noted in our article that not all patients who undergo a refractive surgical procedure to create a multifocal cornea will tolerate the decreased contrast sensitivity and other optical limitations of this procedure. We noted that our technique of leaving a steep central island for near vision has the advantage of allowing the surgeon to subsequently convert this into a monofocal procedure by re-treating and flattening the central region.
Moreira H, Garbus JJ, Fasano A, Lee M, McDonnell PJ, Clapham TN. Corneal Bifocal Effects by Laser Photorefractive Keratectomy-Reply. Arch Ophthalmol. 1993;111(5):582. doi:10.1001/archopht.1993.01090050016008