Choosing Monofocal Intraocular Lenses: Power Adjustment for Young Cataract Patients

Q: Choosing Monofocal Intraocular Lenses: Power Adjustment for Young Cataract Patients

Hello： The advantage of multifocal intraocular lenses is that they allow for both distance and near vision without the need for glasses. <br>However, as you know, the effectiveness of seeing both near and far is not as good as that of monofocal lenses. <br>If you reserve 150-200

Monofocal intraocular lens power calculation?

I am a young patient with cataracts and I am considering surgery, but I am quite confused about the choice of intraocular lenses.
I am concerned about glare while driving at night and whether I can adapt to multifocal lenses.
Some have suggested that I use monofocal aspheric lenses, which seem simpler.
I would like to ask about the degree of myopia to reserve for future near vision needs.
It is generally said to reserve 150-200 degrees of myopia with monofocal lenses.
If that is the case, what distance will I be able to see clearly without reading glasses post-surgery? I understand that I will need reading glasses for small print, but will I also need them for using a computer or smartphone at that distance? Additionally, will I still be able to achieve a distance vision of 0.8-1.0 with the sacrifice of some distance vision?

Xiao Cao, 30~39 year old female. Ask Date: 2011/10/19

Dr. Gao Pilin reply Ophthalmology

Hello: The advantage of multifocal intraocular lenses is that they allow for both distance and near vision without the need for glasses.
However, as you know, the effectiveness of seeing both near and far is not as good as that of monofocal lenses.
If you reserve 150-200 degrees of myopia with monofocal lenses, you generally won't need reading glasses for normal close-up tasks like reading books or using a computer.
However, if you reserve 150-200 degrees of myopia, your distance vision may not reach 0.8-1.0, and you would need to wear myopia glasses to achieve such vision.
If no myopia is reserved, distance vision may reach 0.8-1.0, but for computer use or reading, you would still need reading glasses, as monofocal intraocular lenses cannot adjust focus.
Therefore, with monofocal intraocular lenses, it is inevitable that you will need glasses to achieve good distance or near vision.
If you require better vision, I recommend using aspheric monofocal intraocular lenses.
If you are accustomed to wearing glasses while walking or driving, then reserve the prescription and wear myopia glasses regularly; if you are not used to wearing glasses, then do not reserve, and use reading glasses for close tasks.
Ultimately, it depends on your habits and needs.
Thank you for your message.

Reply Date: 2011/10/19

More Info

Choosing the right intraocular lens (IOL) for cataract surgery, especially for younger patients, can be a complex decision. It’s great that you are considering your options carefully. Let’s break down your concerns regarding monofocal lenses, power adjustments, and the implications for your vision post-surgery.

Understanding Monofocal Intraocular Lenses
Monofocal IOLs are designed to provide clear vision at one specific distance—either near or far. They are a straightforward option that many patients choose, particularly those who are concerned about potential complications from multifocal lenses, such as glare or difficulty adapting to different focal points.

Power Adjustment and Near Vision
When it comes to power adjustment for monofocal lenses, many surgeons recommend leaving a slight degree of myopia (nearsightedness) in younger patients. This is often in the range of -1.50 to -2.00 diopters. By doing this, you can achieve a balance where you can see well at distance while still being able to read or use a computer without needing reading glasses for some tasks.
If you choose to have a -1.50 to -2.00 diopter adjustment, you might find that you can comfortably read at a distance of about 16 to 20 inches without glasses. This is typically the distance for reading small print or using a smartphone. However, for tasks that require prolonged focus, such as working on a computer, you may still need reading glasses, especially if your work involves looking at the screen for extended periods.

Impact on Distance Vision
Regarding your concern about sacrificing distance vision, with a well-calibrated monofocal lens, many patients can achieve visual acuity of 20/25 or better, which is equivalent to 0.8-1.0 on the metric scale. However, this can vary based on individual healing and the specific characteristics of your eyes. It’s essential to have a thorough pre-operative assessment to determine the best power for your lens based on your lifestyle and visual needs.

Nighttime Driving and Glare
Your concerns about nighttime driving and glare are valid. Monofocal lenses, especially non-spherical ones, can help reduce the incidence of glare compared to multifocal lenses. If you are particularly sensitive to light or have concerns about driving at night, discussing these with your surgeon can help tailor your choice of lens to minimize these issues.

Conclusion
In summary, choosing a monofocal IOL with a slight myopic adjustment can provide you with a good balance of distance and near vision, potentially allowing you to perform many tasks without glasses. However, for prolonged near tasks, such as computer work, you may still find reading glasses beneficial. It’s crucial to have an open discussion with your ophthalmologist about your lifestyle needs and concerns, as they can provide personalized recommendations based on your specific situation.
Ultimately, the goal is to ensure that you have the best possible vision for your daily activities while minimizing any potential complications. Good luck with your surgery, and I hope you achieve the vision you desire!

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