New eye drops improve aging without glasses. Here’s how they work

When people reach the age of 40 and older, their vision begins to deteriorate. For many people, increasing the font of the phone or increasing the brightness of the computer is the only way to read some text.

This condition is called presbyopia and affects about 128 million people in the United States and more than one billion worldwide.

In late 2021, the US Food and Drug Administration approved a new eye drop to treat presbyopia. As an optometer, I was skeptical at first.

Before the release of these eye drops, called Vuity, people had to have glasses, contact or eye surgery to reduce presbyopia. But after learning how these eye drops work, I realized that for many people, they can offer an easy and safe way to see clearly again.

The pupil and lens are important parts of the eye involved in drawing attention to objects. (ttsz / iStock / Getty Images)

How to turn your eyes

Many parts of the human eye interact with the incident light to create a clear image.

The first thing that touches the light is the open outer layer that bends the light first. The light then passes through the pupil and iris, which may shrink or enlarge to allow more or less light to enter the eye. It then passes through the lens, which further bends the light and focuses it precisely on the center of the retina. Finally, the light signal is transmitted to the optic nerve behind the eye so that the brain can interpret it as an image.

To get a clear image, your eyes must adjust to the distance to the object. Your eyes take three basic steps to focus on the objects closest to your face: your eyes focus on the object you want to look at, your lenses change shape, and your pupils narrow.

When you look at something that interests you, the tiny muscles of the eye contract, change the shape of the lens, and become thicker. The thicker the lens, the more it bends as light passes through. At the same time, your eyes are narrowed to block some of the light coming from other objects in the distance.

When light jumps from something and enters your eyes, the rays of light in the center provide a clear image. Blocking the scattered light by squeezing the pupil of the eye helps to sharpen the image of nearby objects.

You can imitate this process with the camera on your mobile phone. First, aim the camera at something far away. Then hold your thumb about 6 inches away and move it to the picture. Your thumb begins to blur, but as the shape of the camera lens changes, your finger becomes the focus.

(BruceBlaus / WikimediaCommons / CC BY-SA)

PHOTO: Presbyopia hardens the lens of the eye, and when a person cannot bend the lens easily, he cannot concentrate the incoming light on the right part of the retina, and the images appear blurry.

What is presbyopia?

Presbyopia is the inability to focus on objects close to the eye, resulting in blurred images. It starts at the age of 40 and lasts until the age of 60.

Scientists know that age is the main driver of presbyopia, but there is controversy over its mechanical causes.

One theory suggests that as lenses wear out, they become heavier and cannot easily change shape. According to another theory, the muscle that draws the lens weakens with age. I think presbyopia is caused by a combination of both.

Regardless of the cause, as a result, when looking at nearby objects, the human eye is unable to bend to direct the incoming light to the center of the retina. Instead, light is concentrated behind the retina, causing blurred vision.

How eye drops work

Remember, the eye does two main things to focus on nearby objects: the lens changes shape and the pupil shrinks. Because presbyopia limits the ability to change the shape of the lens, these eye drops cause the pupil to shrink.

Squeezing the pupil reduces the scattering of light. This ensures that the light entering the eye is better concentrated in the retina, thus creating a wider range of focal lengths and allowing people to see objects near and far.

After applying the drops to your eyes, it takes about 15 minutes for the active ingredient pilocarpine to start working. Pilocarpine was first discovered in the late 1800s and treats conditions such as glaucoma and ocular hypertension. The effect on the pupils lasts about six hours.

If the pupils are small, this means that less light enters the eye. Although this is not a problem during long days, it can be difficult to see in low light conditions. In addition to these side effects, the most common side effects of drops are headaches and redness of the eyes.

(MikeRun / WikimediaCommons / CC BY-SA)

PHOTO: Reducing the pupil and less light entering the eye increases the depth of the field.

Presbyopia in the future

Vuity is currently approved for single use on each eye. A bottle costs about $ 80, requires a prescription, and lasts for almost a month if used daily. For some people, these glasses may be a great alternative or supplement to surgery.

Vuity may be the first eye drops approved by the FDA to treat presbyopia, but researchers are exploring a number of other methods. Some, like Vuity, are developing eye drops that contain non-steroidal anti-inflammatory drugs to help compress the pupil.

Other teams are exploring lens weight softening and reducing drops to ease focus. Finally, some preliminary studies have shown that pulsed electrical stimulation of the eye muscles helps to strengthen them and improve people’s ability to bend lenses. A talk

The future of presbyopia treatment is exciting, as researchers are working on many potential ways to overcome this universal condition of aging. So far, Vuity – although not a magic cure for all people with presbyopia – is an innovative option and you should ask your eye doctor about it.

Robert Bittner, Assistant Professor of Ophthalmology, University of Pittsburgh Public Health

This article was reprinted from The Conversation magazine under a Creative Commons license. Read the original article.

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