Is It Safe to Alternate Between Glasses with Different Astigmatism Levels?

Is astigmatism commonly corrected with a prescription of 25 degrees?

Hello, doctor.
Four months ago, my right eye was measured at -75 degrees with -50 degrees of astigmatism, and my left eye was -100 degrees with -50 degrees of astigmatism.
My old glasses were prescribed with these measurements.
Now, my right eye is -100 degrees with -50 degrees of astigmatism, and my left eye is -125 degrees with -25 degrees of astigmatism.
My new glasses are prescribed for the right eye at -25 degrees with -50 degrees of astigmatism, and for the left eye at -50 degrees with -25 degrees of astigmatism.
I plan to use my old glasses for driving or viewing distant screens, while the new glasses will be for work, focusing on the computer and phone.
The optometrist mentioned that using lower prescriptions would be less tiring.

I would like to know if having a 25-degree difference in astigmatism between my two pairs of glasses will have any impact on my eyes when alternating their use.
Given that my current measurement for the left eye is -25 degrees of astigmatism, is it appropriate to wear lenses with -50 degrees of astigmatism? Additionally, is it acceptable to use my old glasses for looking at my phone or computer (when I am too lazy to switch to the new glasses), or should I always use the lower prescription glasses for near tasks? Thank you!

En, 20~29 year old female. Ask Date: 2021/08/23

Dr. Gao Pilin reply Ophthalmology

Hello, as long as you can see clearly with a difference of 25 degrees, it's not a problem.
Given your age and that your prescription is not high, you don't necessarily need to switch to lower prescription glasses for computer use.
If you can see clearly without glasses, it's not mandatory to wear them.

Reply Date: 2021/08/23

More Info

When it comes to alternating between glasses with different levels of astigmatism, there are several factors to consider. Your situation involves using two pairs of glasses: one with a higher prescription for distance vision and another with a lower prescription for computer work. This is a common practice, especially for individuals who have varying visual needs throughout the day.

Firstly, it is essential to understand how astigmatism affects vision. Astigmatism occurs when the cornea or lens of the eye is irregularly shaped, leading to blurred or distorted vision. The degree of astigmatism is measured in diopters (D), and it can vary between individuals. In your case, you have different prescriptions for each eye, which is typical for many people.

Using your old glasses with a higher prescription (right eye: 100D, left eye: 125D) for activities like driving or watching a screen from a distance is generally acceptable. These glasses are designed to correct your vision for far distances, which is necessary for safe driving. However, they may cause some discomfort or visual fatigue if used for prolonged periods while looking at close-up screens, such as computers or smartphones. This is because the higher prescription may not provide the optimal comfort for near vision tasks.

On the other hand, your new glasses with lower prescriptions (right eye: 25D, left eye: 50D) are tailored for close-up work, which can help reduce eye strain when working on a computer or using a smartphone. The optometrist's recommendation to use lower prescriptions for these tasks is sound, as it can help prevent fatigue and discomfort associated with prolonged near vision activities.

Regarding the difference in astigmatism levels between your two pairs of glasses, it is generally safe to alternate between them as long as you are mindful of your comfort and visual clarity. The left eye's astigmatism difference (25D) between the two pairs is relatively minor, and many people successfully adapt to slight variations in their prescriptions. However, if you notice any significant discomfort, headaches, or visual disturbances while switching between the two pairs, it may be worth consulting your optometrist for further evaluation.

As for using your old glasses for close-up tasks, it is not ideal but can be done occasionally if you find it convenient. However, it is recommended to switch to your new glasses for prolonged near vision tasks to ensure optimal comfort and reduce the risk of eye strain. If you find yourself frequently switching between tasks, consider keeping your new glasses handy for close-up work and your old glasses for distance tasks.

In summary, alternating between glasses with different astigmatism levels is generally safe, provided you pay attention to your comfort and visual needs. It is essential to use the appropriate glasses for the specific tasks you are performing to minimize eye strain and maintain visual clarity. If you have any ongoing concerns or experience discomfort, do not hesitate to reach out to your optometrist for personalized advice and adjustments to your prescriptions.

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