<Things you should know> The correct knowledge about presbyopia: Causes, symptoms, and treatments for presbyopia
While presbyopia (age-related farsightedness) is often associated with the elderly, it's actually said that symptoms begin to appear in people in their 30s and 40s. We'll provide accurate information on the symptoms, causes, and treatment options, and an ophthalmologist will also explain "smartphone-induced presbyopia," which has recently spread to people in their teens and twenties.
![What is presbyopia?]()
What is presbyopia?
The basic symptom of presbyopia is difficulty seeing things up close when you're wearing glasses or contact lenses to see things far away. It's often said that "people who are nearsighted don't get presbyopia," but that's wrong. There is no correlation between nearsightedness, farsightedness, or astigmatism and presbyopia, and it is said that everyone will develop presbyopia as they age. Symptoms generally begin to appear gradually from around the age of 30, and presbyopia progresses until around the mid-40s.
Main symptoms of presbyopia
The main symptoms of presbyopia include the following:
- Small print is hard to read.
- It's hard to see what's right in front of you.
- It is difficult to see things in dark places.
- Eye fatigue
- headache
- Stiff shoulders
![Main symptoms of presbyopia]()
Before these clear symptoms appear, early-stage presbyopia may manifest as blurred vision in the distance after prolonged close-up viewing in the evening.
This occurs because during the day, we often look at things up close for work, causing our eyes to become fixed in a near-focus position, making it difficult to focus on distant objects in the evening. Other specific symptoms include eye strain and dry eyes.
![Causes and mechanisms of presbyopia]()
Causes and mechanisms of presbyopia
Next, let's look at the mechanism by which presbyopia occurs.
Of the various parts of the eye, the "lens" and the "ciliary muscle" are particularly involved in presbyopia (age-related farsightedness).
The lens of the eye acts like the lens of a camera, and the ciliary muscle adjusts the thickness of the lens to focus. The ciliary muscle controls focus by pulling and relaxing the lens. When the ciliary muscle tenses and contracts, the lens thickens, allowing you to focus on nearby objects. However, as we age, the lens hardens and loses its elasticity, so even when the ciliary muscle tenses, the thickness of the lens no longer changes. As a result, you can no longer focus on nearby objects, making it difficult to see things up close—this is known as presbyopia.
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The mechanism of presbyopia
![Presbyopia caused by smartphones can develop even in young people.]()
Presbyopia caused by smartphones can develop even in young people.
We've explained that presbyopia is caused by the hardening of the lens of the eye due to aging, and that even if the ciliary muscle contracts, the thickness of the lens doesn't change, making it difficult to focus on nearby objects. However, similar symptoms can also occur in younger people in their teens and twenties. This is due to the lifestyle habit of staring at smartphone and computer screens for long periods of time, and is called "smartphone presbyopia."
There are two types of smartphone-induced presbyopia: accommodative relaxation type and accommodative spasm type.
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Smartphone-induced presbyopia (age-related farsightedness) due to accommodative flaccidity
If a nearsighted person goes without glasses or contact lenses and spends long hours looking at their smartphone without them, the ciliary muscle's focusing function is not used, and the lens does not move. As a result, the lens gradually loses its elasticity. When they then use glasses or contact lenses to see things far away, they experience symptoms similar to presbyopia, such as difficulty seeing things up close.
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Accommodative spasm type smartphone-induced presbyopia
When you wear glasses or contact lenses and look at your smartphone for extended periods, the ciliary muscles remain contracted and unable to relax, and the lens of the eye remains thickened and unable to thin. As a result, you lose the ability to adjust your focus, which is the cause of this type of vision problem.
Unlike age-related presbyopia, smartphone-induced presbyopia in younger people is often said to be reversible. Symptoms can be expected to improve by doing the "eye stretches" described in the next section and using eye drops that help smooth focusing, but if you are young and experience symptoms similar to presbyopia, you should first consult an ophthalmologist.
![How to deal with presbyopia]()
How to deal with presbyopia
It's impossible to prevent presbyopia (age-related farsightedness) due to aging. Ignoring presbyopia and pushing yourself too hard can lead to various health problems, not just eye strain, so age-appropriate measures are essential. With the right approach, you can live comfortably.
![countermeasure]()
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Use of bifocal glasses or contact lenses
If you start using bifocal glasses or contact lenses after your presbyopia has progressed, you may experience distorted vision or difficulty focusing, making them difficult to use. Ideally, if you start using them before your presbyopia progresses, ideally before the age of 40, you will be able to use them comfortably even as your presbyopia worsens. In recent years, bifocal glasses have continued to evolve, and there are many designs and appearances that people under 40 can use without hesitation.
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Eye stretches
This eye exercise is also effective for smartphone-induced presbyopia, as explained earlier, and can be done even while wearing glasses or contact lenses.
Keeping the same focus for extended periods is bad for your eyes, so when looking at something up close for a long time, consciously shift your gaze to a distant point (just within the range of focus) about once every 10 minutes, and then return it to its original position once it's in focus. Shifting your focus causes the ciliary muscle and lens to move, and the blood vessels within the ciliary muscle also expand and contract. This is said to improve blood circulation and reduce eye strain. Looking upwards (towards the ceiling) instead of horizontally is also recommended.
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Foods containing astaxanthin and lutein
Astaxanthin and lutein remove free radicals, thus relieving eye strain.
The red color of salmon, salmon roe, shrimp, and crab comes from astaxanthin. Lutein is found in spinach, broccoli, pumpkin, and carrots. If it's difficult to get enough through diet, you can supplement with supplements.
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Eye drops that relieve eye strain
Eye drops containing neostigmine methylsulfate can help relieve eye strain. They are also effective in combating presbyopia caused by smartphone use.
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Light exercise before bed
Lack of sleep impairs the ability of your eyes to focus properly, so quality sleep is essential. Sleep is deeply connected to the autonomic nervous system (sympathetic and parasympathetic nerves). The sympathetic nervous system is dominant when you are awake or stressed, while the parasympathetic nervous system is dominant when you are sleeping or relaxed.
Sleeping when your body switches from the sympathetic to the parasympathetic nervous system improves your ability to fall asleep. When you're looking at something close up, the parasympathetic nervous system is dominant. If you look at your smartphone or other devices before bed, try doing some light exercise afterward, such as stretching or marching in place. Moving your body once will activate the sympathetic nervous system, which will help you fall asleep more easily.
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How to choose bifocal glasses (reading glasses)
The basic procedure is to have your eyes examined at an ophthalmologist's office that frequently prescribes eyeglasses, and then take that prescription (instruction sheet) to an eyeglasses store to have glasses made. Some eyeglasses stores can perform eye examinations, but in Japan, there is no national qualification for measuring vision or selecting appropriate lenses. As a guideline for someone with solid knowledge, there is a qualification called "Certified Optician" certified by the Japan Opticians Association. You can also search for stores with certified opticians on the association's website.
![Common examination methods at hospitals (ophthalmology departments)]()
Common examination methods at hospitals (ophthalmology departments)
When getting reading glasses or bifocal glasses/contact lenses, the examinations performed at an ophthalmologist include visual acuity tests, slit-lamp microscopy, and fundus examination. In addition, intraocular pressure and visual field tests are performed as needed. These tests also serve to check for underlying conditions such as cataracts and glaucoma.
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Vision test
Tests to determine the degree of nearsightedness, farsightedness, astigmatism, etc.
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Slit-lamp microscopy
This is an examination that uses a thin beam of light to check for injuries or inflammation in the eye.
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Fundus examination
This examination involves taking photographs of the fundus of the eye using a fundus camera to check for bleeding or other abnormalities.
![Common concerns about presbyopia (Q&A)]()
Common concerns about presbyopia (Q&A)
Finally, we will answer some common questions you may have about presbyopia (age-related farsightedness).
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Can presbyopia be cured?
Unfortunately, presbyopia cannot be cured. However, you can live comfortably by using bifocal glasses or contact lenses.
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Is it okay to leave presbyopia untreated?
If you push yourself too hard, you may experience not only eye strain and stiff shoulders, but also various other physical ailments. Therefore, be sure to use glasses or contact lenses that are suited to your vision.
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Do people with nearsightedness develop presbyopia (age-related farsightedness)?
As explained at the beginning, everyone can develop presbyopia. Even nearsighted people can develop presbyopia if they have difficulty seeing things up close even when their eyes are clear at a distance.
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Does your eyesight deteriorate as you get presbyopia (age-related farsightedness)?
Presbyopia does not change your eyesight. However, as people age, their eyes tend to shift towards hyperopia, making it difficult to see both far and near objects clearly. Therefore, people with good eyesight tend to have difficulty seeing both far and near objects, while those with strong myopia tend to experience a slight decrease in their degree of myopia.
Supervised by: Dr. Masayoshi Kajita, Director of Kajita Eye Clinic
After graduating from Fukushima Medical University in 1983, he worked as a researcher at the University of California, Berkeley, before opening Kajita Ophthalmology Clinic in 2003. From 2018 to 2021, he served as a Clinical Professor at Tokyo Medical and Dental University School of Medicine. In 2022, he was awarded Honorary Membership by the Japan Contact Lens Society, and in 2023, Honorary Membership by the Japanese Society of Ophthalmic Optics. He currently serves as a councilor of the Japan Ophthalmological Society and a member of the drafting committee for the Japanese Medical Optics JIS standards.