Choosing the Right Lens Power for Cataract Surgery: 0 vs 300 Degrees

Q: Choosing the Right Lens Power for Cataract Surgery: 0 vs 300 Degrees

Hello： 1. Leave 300 degrees for both eyes on average, which makes it easier to fit glasses. 2. Having both eyes at an average degree is more comfortable. There is no need to intentionally use binocular disparity. 3. If both eyes are left at 300 degrees, it

For a patient who has undergone cataract surgery on the right eye with a residual refractive error of +3.00 diopters, is it appropriate to select a 0 diopter lens for the left eye?

(1) Current Status: The mother is currently 69 years old and has cataracts in both eyes, along with diabetes and hypertension (which are under control).
Three years ago (in 2019), cataracts were discovered alongside macular edema, leading to injection treatment for about three years.
Prior to surgery, her myopia was over -500 diopters in both eyes, presbyopia was approximately +300 diopters, and astigmatism is unknown.
She has had about 250 diopters of anisometropia since elementary school and has always worn glasses; she removes them for close-up tasks.
At the end of last year, she underwent surgery on her right eye (with a single-focus intraocular lens from "Zeiss"), leaving +300 diopters.
At that time, she decided to leave +300 diopters without much thought, and now she is preparing for surgery on her left eye and wishes to be more cautious.

(2) Current Eye Measurements (measured on 11/3/6, with both eyes still having edema at that time, which has since resolved): Right eye approximately -350 diopters with 50 diopters of astigmatism at an axis of about 90 degrees; visual acuity seems to be only 0.3.
With corrective lenses, she can watch TV comfortably, but can only use her phone for close-up tasks, unable to read newspapers.
Left eye approximately -325 diopters with 75 diopters of astigmatism at an axis of about 70 degrees; presbyopia is approximately +300 diopters in both eyes.
(3) Inquiry Content:
1.
Given the overall condition of the elder, would it be more advisable to leave the other eye at 0 diopters or also at +300 diopters? The attending physician's habit is to avoid anisometropia between the two eyes, hence the recommendation to leave +300 diopters, but it was indicated that leaving 0 diopters is also an option.
Based on research, I understand that both options have their pros and cons.
Considering my mother’s age (69 years) and medical history (diabetes and previous macular edema, with uncertainty about future edema), would it be suitable to leave the left eye at 0 diopters?
2.
I want to confirm my understanding: Although my mother has had anisometropia since childhood, she has always worn glasses, so we cannot assume that she would adapt to a new anisometropia if the right eye is +300 diopters and the left eye is 0 diopters, as she did not experience anisometropia while wearing glasses.
3.
If the right eye is +300 diopters and the left eye is 0 diopters, and she experiences persistent dizziness, are there other solutions besides removing her glasses? Note: My retired mother’s primary visual need is watching TV, with occasional phone use, and she only requires distance vision for reading license plates about once a week.
Thank you!

Bang Zhangbei Xunwen (Nianling 69 sui shi muqin nianji), 60~69 year old female. Ask Date: 2022/06/01

Dr. Gao Pilin reply Ophthalmology

Hello: 1.
Leave 300 degrees for both eyes on average, which makes it easier to fit glasses.
2.
Having both eyes at an average degree is more comfortable.
There is no need to intentionally use binocular disparity.
3.
If both eyes are left at 300 degrees, it is more convenient for her daily life since she is accustomed to wearing glasses.
She won't need to wear them when looking at her phone, which is no different from her previous habits.

Reply Date: 2022/06/01

More Info

When considering cataract surgery for your mother, particularly in the context of her existing health conditions and visual needs, there are several important factors to weigh regarding the choice of lens power for her left eye.

1. Choosing Between 0 Degrees and 300 Degrees
Given your mother's age (69 years) and her medical history, including diabetes and previous macular edema, the decision on whether to leave her left eye at 0 degrees or 300 degrees should be made with caution. The recommendation from her ophthalmologist to maintain a similar lens power in both eyes (300 degrees) is based on the principle of minimizing visual disparity, which can lead to discomfort and difficulties in visual coordination.
However, if your mother has specific visual needs or preferences, such as a desire to see better for near tasks without glasses, leaving the left eye at 0 degrees could be beneficial. It’s essential to consider her lifestyle; if she primarily watches television and occasionally uses her phone, having one eye set for distance (300 degrees) and the other for near vision (0 degrees) could provide a functional balance.

2. Understanding Visual Disparity
You are correct in noting that while your mother has had a history of anisometropia (difference in refractive power between the two eyes), her experience with corrective lenses means she has adapted to a specific visual system. The adaptation to a new visual disparity (one eye at 300 degrees and the other at 0 degrees) may not be as straightforward as it was when she was younger. The brain can adapt to some degree of visual difference, but significant disparities can lead to discomfort, headaches, or dizziness.

3. Managing Potential Discomfort
If your mother undergoes surgery and ends up with one eye at 300 degrees and the other at 0 degrees, and experiences dizziness or discomfort, there are several strategies to consider:
- Gradual Adaptation: Allowing time for her brain to adapt to the new visual inputs is crucial. This may take several weeks.

- Vision Therapy: In some cases, vision therapy can help individuals adapt to new visual conditions, especially if there are issues with coordination between the eyes.

- Use of Glasses: If the disparity causes significant discomfort, using glasses that balance the vision between the two eyes may help. For example, glasses that provide a slight correction to the eye set at 0 degrees could help in reducing the visual disparity.

- Follow-Up with the Ophthalmologist: Regular follow-ups with her eye doctor post-surgery will be essential to monitor her adaptation and address any concerns.

Conclusion
Ultimately, the decision on whether to leave the left eye at 0 degrees or 300 degrees should be made collaboratively with her ophthalmologist, considering her specific visual needs, lifestyle, and the potential for adaptation. It’s important to weigh the benefits of having one eye optimized for distance and the other for near vision against the risks of discomfort due to visual disparity. Given her health conditions, close monitoring after surgery will be essential to ensure the best possible outcome.

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