As opticians, our professional lives revolve around producing prescription eyeglasses and contact lenses, of which, a large percentage treat presbyopia. When I read the headline “FDA Approves Allergan’s Vuity, the First Eye Drop for Treating Presbyopia” in Vision Monday, my first thought was bye, bye progressive and reading lenses! While this is an exciting new tool in the presbyopia treatment toolbox, it will not replace reading eyewear whether progressives, lined multifocal or reading glasses.
How does it work? The pilocarpine-based eye drops are miotics that constrict the pupil, creating a pinhole-camera effect allowing us to focus on intermediate distance objects and near objects more clearly. A pinhole restricts the amount of light reaching the retina to a small amount of focused light rays. By reducing or eliminating defocused rays, the remaining rays are clearly focused on the retina. The same principal applies when we squint because by narrowing the aperture (lids), we reduce the amount of defocused light entering the eye and therefore see more clearly.
Additionally, pilocarpine causes a mild contraction of the ciliary muscle. When the ciliary muscle is contracted, the tension on the zonular fibers relaxes, allowing the lens to become more spherical in shape (plus power) thereby increasing its focal power. For the miotics action on the ciliary muscle contraction to improve close vision, the crystalline lens must have enough accommodative amplitude (the ability of the lens to change shape when the ciliary muscle contracts) for near focus, but by age 55, most lack sufficient accommodation because the crystalline lens has become dense and rigid, and no longer responds when the ciliary muscles contract.
So, is this exciting news? Yes. Is it a game changer? Yes. Does it have a place in presbyopia treatment? Yes. But will we be able to say bye, bye to progressive and reading lenses? No! In the words of Michael Rowe, COO of Eyenova: “None of the miotics can quite take the place of reading glasses… Reading your cell phone will probably be possible. Grading term papers? Not so much. Instead, the drugs can serve as an alternative to be used in a social situation or very active situation where reading glasses are undesirable. The way we look at it, it’s almost like getting a second pair of reading glasses. But the second pair is your invisible pair.”
• Deborah Kotob
Pro to Pro Director