Hirokazu Kobayashi
CEO, Green Insight Japan, Inc.
Professor Emeritus and Visiting Professor, University of Shizuoka
Approximately 1,000 years ago, during the Heian period in Japan, the blind elderly mother Zushioh met at the end of “Anju and Zushioh'', may have suffered from cataracts. The most common eye diseases among the elderly are cataracts, glaucoma, and age-related macular degeneration, and it is said that 60-70% of people aged 65 and over have cataracts. Cataracts were a difficult disease to treat until around 2000. It was a given that older people had poor eyesight, and we had no choice but to accept that. We were born in good times. I started to find it challenging to read highway signs while driving and the text on slides projected on screens. I tried different glasses, but the problem persisted. It was not until I turned 55 that I decided to visit an ophthalmologist to get it checked out. I was diagnosed with cataracts and was told that although medication could slow the progression, surgery was the only way to improve her symptoms (I had developed the disease earlier than average). I visited a different eye doctor for a second opinion, and this doctor agreed with the first doctor's diagnosis. Therefore, the decision was made to undergo surgery, and the core technology of this surgery was the ultrasonic emulsification of the gelled contents of the crystalline lens and the introduction of an intraocular lens that folds up and opens after insertion.
The next decision remained whether to opt for a monofocal or multifocal intraocular lens. Monofocal lenses are designed to focus on either distant or close objects, and usually, far vision is chosen, resulting in the requirement of reading glasses for near vision. On the other hand, multifocal lenses can provide clear vision for both near and far distances. Although the latter are not typically covered by insurance in Japan and are more expensive, they are made using the latest technology. Since replacing lenses frequently can be difficult, I have decided to opt for multifocal lenses. From my understanding, most ophthalmologists suggest using mono-focal lenses instead of multifocal lenses, as some patients may not find the multifocal ones comfortable. I have had a positive experience with multifocal lenses and no longer require glasses for near and far distances with vision "1.0". However, when using a desktop computer with a medium distance, it is still more manageable to see if I wear glasses. This is because when I got my multifocal lenses in 2010, the technology was not as advanced as today. The lens that was called "multifocal" was only bifocal. Our brain is an amazing organ that can distinguish between sharp and blurry images. When we look through bifocal lenses, our brain identifies only the sharp picture, even though the sharp and blurry images are reflected in our retinas. However, at night, we experience a different phenomenon. When we look at a light source, we cannot eliminate the blurred image, resulting in a halo or glare. Over time, we become accustomed to this experience, and it no longer feels strange. Recently, I have heard complaints from people who have had trifocal lenses fitted, saying they have difficulty seeing things up close. Because trifocal lenses focus on medium-range distances, it is disadvantageous that the light needed for sharp images at close range is less than one-third. I can also agree with the recommendation for single-vision lenses for people who are used to wearing glasses and for people who do detailed work. Based on my experience, if you want to stay active, you should wear double-focus; if not, you should wear single-focus.

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