[Este artículo está disponible en español. La traducción al español apareció por primera vez en la revista Pensar.]
You’ve probably seen the ads. Vuity is a new prescription eyedrop. An article in Scientific American says, “These drops could replace your reading glasses.” Could they really? How can that be? Do they really work? Kind of, sort of … for some people … for a few hours … maybe. It’s no panacea. The devil is in the details.
As we get older, our arms get shorter. No, not really, but it may seem like it. Print gets blurry up close. We have to hold a menu at arm’s length to read it. Most of us eventually resort to reading glasses.
It’s called presbyopia. That’s Greek for “old eyes.” It’s a normal part of aging. The lens loses flexibility and has difficulty focusing on nearby objects, so these appear blurry. The eyedrops shrink the pupil, blocking extraneous light from more distant sources and bringing nearby objects into sharper focus. The effect is similar to what happens when you reduce the aperture on a camera lens or when you use pinhole glasses.
The drug in the eyedrops was only recently approved for this new indication, but it’s not a new drug. It’s pilocarpine, which was discovered in 1874 and has been used for over a century to treat glaucoma. It makes the eye muscles contract and opens channels that drain fluid from the eye, reducing intraocular pressure.
It has several well-known side effects. As eye drops, it can cause a mild headache (known as brow ache), temporary blurred vision or darkness of vision, increased tearing, temporary shortsightedness, hyphema, and retinal detachment. It only starts to work after fifteen minutes, and the effects wear off after about six hours. In dim light, the pupil enlarges to let more light in; it can’t do that when pilocarpine is used, and that could be a problem for night driving. The reporters who tried it for Scientific American said it reduced but did not eliminate the fuzziness of text on their phones, and for them, the effect only lasted about three hours. Testimonials elsewhere report that it failed to work for some people, that it caused a stinging sensation, that it caused redness of the eyes, and that it made everything look dimmer. It has not been tested for safety during pregnancy, and it doesn’t appear to work as well for older people.
In clinical trials, about 30 percent of patients were able to read three additional rows on an eye chart held at arm’s length. It’s much more expensive than the generic pilocarpine used for glaucoma. A month’s supply costs anywhere from $75 to $105, and it’s not covered by insurance. The company justifies the higher price by saying they changed the formulation so the drops would sting less.
In short, these drops are no panacea. Although they may reduce the need for reading glasses for a few hours, they will not eliminate the need for reading glasses for most people. They are expensive, and they cause headaches and other side effects for many patients. Research is ongoing, and better products may soon be available. Stay tuned.
This article was originally published in Skeptical Inquirer.
