Lens Focal Length: Addressing Discomfort with New Glasses

Q: Lens Focal Length: Addressing Discomfort with New Glasses

Hello： 1. <br>There are no studies supporting the above conclusions. <br>2. <br>The tolerance for lens focal length errors depends on the prescription strength; the deeper the prescription for myopia, hyperopia, or vertical astigmatism, the smaller the tolerance. <br>Only horizon

Focal length of glasses

Dear Dr.
Liang,
Last week, my eyeglasses frame was damaged, so I went to the optical store to get a new pair of glasses (only the frame was replaced, not the lenses).
After changing to the new frame, I feel a bit dizzy and lightheaded after wearing them for less than 10 minutes.
The muscles around my eyes feel slightly sore, and there is a sensation of pressure near my temples.
It seems that the focal distance of the glasses does not match my eyes, as I did not experience these symptoms with my old frame.
When I inquired at the optical store, they mentioned that adjusting the frame slightly during the replacement could cause this, and that my eyes might be too sensitive...
(-_-?) They measured and found that the focal distance of the lenses is 2mm further out than my eye's focal distance, but they said that according to "medical literature," a difference of less than 3mm is generally considered acceptable.

Therefore, I would like to ask Dr.
Liang:
1.
Is there really research on this topic?
2.
Generally speaking, what is the acceptable range for the focal distance discrepancy between lenses and the eyes?
3.
If the discrepancy is within an acceptable range but I still experience discomfort such as dizziness and eye muscle soreness, is it better to change the glasses directly, or should I allow my eyes to adjust?
4.
If I wear glasses with such discrepancies for a long time, will it have adverse effects on my eyes?
5.
What does it mean for eyes to be "more sensitive"?
I have asked many questions and hope I am not taking up too much of your time.
Thank you for your response!
Best regards,
Jack

Jack, 20~29 year old female. Ask Date: 2004/05/05

Dr. Liang Ce reply Ophthalmology

Hello: 1.
There are no studies supporting the above conclusions.
2.
The tolerance for lens focal length errors depends on the prescription strength; the deeper the prescription for myopia, hyperopia, or vertical astigmatism, the smaller the tolerance.
Only horizontal astigmatism is unaffected.
3.
Since I do not know your glasses prescription, I cannot determine if it falls within the tolerance range.
However, if symptoms persist beyond a week, it is better to replace them.
It is advisable to choose a frame similar in shape and size to your old glasses.
4.
I cannot provide reasons for points 2 and 3.
5.
Generally, as people age, the longer they have worn their original glasses, and the deeper the prescription (especially with astigmatism), the greater the difference in shape and size between the original frame and the new one.
This can make individuals more sensitive to balance issues (for example, being prone to motion sickness), leading to increased discomfort when wearing new glasses.
Dr.
Liang Ce, Ophthalmology, Miaoli Hospital.

Reply Date: 2004/05/05

More Info

Dear Jack,
Thank you for your detailed inquiry regarding your recent experience with new glasses and the discomfort you are experiencing. It’s not uncommon for individuals to face challenges when transitioning to new eyewear, especially when there are changes in the frame or lens specifications. Let’s address your questions one by one.

1. Research on Acceptable Focal Length Differences: Yes, there is literature in optometry that discusses acceptable tolerances for lens positioning relative to the eye. Generally, a difference of up to 2-3 mm is considered acceptable for most individuals. However, this can vary based on individual sensitivity and the specific design of the lenses. Some people may be more sensitive to even minor discrepancies, which could explain your discomfort.

2. Acceptable Range for Lens and Eye Focal Length: As mentioned, a difference of less than 3 mm is typically deemed acceptable. However, the comfort level can vary significantly among individuals. Some may find even a 1 mm difference noticeable, while others may not. It’s essential to consider how the lenses are aligned with your pupils and how they interact with your visual system.

3. Dealing with Discomfort: If you are experiencing symptoms like dizziness and muscle strain around your eyes, it is advisable to consult with your optometrist or ophthalmologist. While some individuals can adapt to minor discrepancies over time, persistent discomfort is a sign that the lenses may not be suitable for you. If the discomfort continues, it may be best to consider a replacement or adjustment of the lenses rather than forcing your eyes to adapt.

4. Long-term Effects of Wearing Incorrect Glasses: Wearing glasses with a significant focal length error can lead to eye strain, headaches, and potentially worsen your vision over time. It’s crucial to address any discomfort promptly to avoid developing a reliance on incorrect visual aids, which could lead to further complications.

5. Understanding "Sensitive" Eyes: When we refer to "sensitive" eyes, it typically means that the individual experiences discomfort or adverse reactions to various stimuli, including light, lens materials, or even the fit of the glasses. This sensitivity can manifest as headaches, eye strain, or a feeling of pressure around the eyes. It’s essential to communicate these sensitivities to your eye care provider, as they can help tailor solutions to your specific needs.

In conclusion, while some discomfort can be expected when adjusting to new glasses, persistent symptoms warrant further investigation. It’s essential to ensure that your lenses are correctly aligned and suited to your visual needs. I recommend returning to your optometrist for a thorough evaluation and discussing your symptoms in detail. They may suggest adjustments or even a new prescription to ensure your comfort and visual clarity.

Thank you for your thoughtful questions, and I hope this information helps you navigate your current situation. Please don’t hesitate to reach out if you have further concerns.

Best regards,
Doctor Q&A Teams

Similar Q&A

Struggling with New Glasses: Headaches and Vision Issues Explained

I have been wearing glasses for over ten years, and my eyesight has progressed into the high myopia category. I have changed more than ten pairs of glasses, including glass, plastic, spherical, and aspherical lenses. I always go to the same ophthalmology clinic (because I feel co...

Dr. Wang Zhishun reply Ophthalmology
Hello, if vision is clear with one eye and the eye alignment is normal, but dizziness occurs only when using both eyes, it is likely due to a technical issue with the lens grinding. The focal length may be incorrect, and it would be better to regrind the lenses. For distance visi...

Choosing Different Intraocular Lenses for Each Eye: Impacts on Vision

Dear Director Gao, 1. My right eye has severe myopia and after developing cataracts, the prescription increased to -1000 diopters. I underwent cataract surgery in March last year, using the "Rein" aspheric monofocal intraocular lens, with a planned myopic reserve of -1...

Dr. Gao Pilin reply Ophthalmology
Hello Mr. Lee: 1. Different brands will not exhibit this phenomenon. You can follow your physician's recommendations. 2. Depending on your needs, if you want to wear glasses all the time, you can choose the same prescription as your right eye. If you prefer not to wear gl...

Impact of Alternating Glasses with Different Focal Lengths on Eye Health

Hello, Doctor. I would like to ask you about my situation. Since I often read at close distances at home, I have a pair of glasses with a prescription of -2.50 diopters and a pupillary distance (PD) of 61 mm that I use regularly. When I go out, I use another pair of glasses with ...

Dr. Gao Pilin reply Ophthalmology
Hello, the interpupillary distance (IPD) for near vision is generally smaller, and the prescription can also be reduced. Therefore, this exchange should not have any significant impact.

Struggles with Glasses: Finding the Right Fit for My Vision Needs

Hello, Doctor. I have high myopia in both eyes, exceeding -6.00 diopters, and astigmatism close to -2.00 diopters. Additionally, I have cervical disc herniation, which may be affecting my eye's ability to accommodate. I have two pairs of glasses that I started wearing during...

Dr. Gao Pilin reply Ophthalmology
Hello: From your description, it seems that you haven't had an eye examination. I recommend visiting an ophthalmologist to have your vision checked and to determine the correct prescription. It seems like there might be an issue with your prescription.