The reason is simple. It is a natural phenomenon that occurs when the lens crystals in the eye regulate the power of the lens, and the muscles that move the lens lose strength due to aging. Just as running slows down with age, so does every function in the eye.

  Symptoms of aging begin to appear in the mid-40s, but depending on the person, they can occur as early as the late 30s, or in the late 40s for those with healthy eye strength, with the average age being around 45.

  Some customers say, "I can read very well without my glasses," so they don't have presbyopia, but reading without glasses is presbyopia in itself.
The reason why you take off your glasses is because you can't see with them on, and the reason why you take them off is because they have different degrees of presbyopia. In the case of myopes, who usually wear glasses all the time because they can't see far away when they are young, they can see the text well when they take off their glasses, but they keep putting on and taking off their glasses and visit an optometrist because they are uncomfortable. In order to avoid taking them off and on, you need to wear progressive, multifocal, or progressive lenses. In fact, when I first started practicing optometry in the mid-90s, multifocal lenses were rarely used. It was not easy to sell progressive multifocal lenses because the price was very expensive, the technology was not as digital as it is now, and the lenses had an analog design, and there were many complaints about the narrow viewing area, and there were many misunderstandings about progressive multifocal lenses as they were passed on to people around them with doubts about why the glasses they paid a lot of money for were like this.
So, even nowadays, customers who come to us often ask, "My friend said that I can't use them because they are too dizzy, and I just stay at home, but can I use them?".

  To clear up that misunderstanding..., the lenses that come out nowadays have more upgraded features than the old lenses, so those who can easily adapt to them can do it in 1 hour, and on average 3-4 days, so don't worry. That's true. They do adjust very well.

  However, you can't just say, "Just adjust without understanding the design of the lens," and for first-time multifocal lens customers, we explain the detailed lens design and the understanding required for adjustment. To be more specific, everyone's eye shape, degree of myopia, astigmatism, hyperopia, presbyopia, and lifestyle will determine the adjustment time. We will explain this in the next part. (1)