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  • Writer's pictureHirokazu Kobayashi

Multifocal lenses for cataracts are made possible by the brain's processing power!

Updated: May 9

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 difficult 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. Considering that replacing lenses frequently can be difficult, I have decided to opt for multifocal lenses. From my understanding, most ophthalmologists suggest using monofocal 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. However, when using a desktop computer where the distance is medium, it is still easier for me to see if I wear glasses. This is because when I got my multifocal lenses in 2010, the technology was not as advanced as it is today and the lens that was called "multifocal" was actually 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 image, even though the sharp and blurry images are reflected on 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. If you are still active, I would suggest multifocal lenses as they are better suited for such individuals. On the other hand, if you are less active, monofocal lenses may be a better option.




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