Common Eyeglass Questions: Choosing the Right Prescription and Sunglasses

Q: Common Eyeglass Questions: Choosing the Right Prescription and Sunglasses

Hello, Mr. <br>Lu：<br>When experiencing eye fatigue, the results of an eye examination may show a higher degree of myopia. <br>Therefore, if subsequent measurements indicate a lower degree, it is advisable to prescribe a lower prescription. <br>The degree measured after dilation

Questions about getting glasses?

Hello, Doctor Gao.
Thank you for taking the time to address my concerns despite your busy schedule.
I have a few questions I would like to ask you.
My glasses prescription is -3.50 and -4.00 diopters, which I obtained from a regular optical store.
However, during a recent eye examination, the ophthalmologist mentioned that my glasses prescription exceeded my original prescription, leading to early presbyopia symptoms.
The measurement taken during that visit was -4.00 diopters.
Is it possible that my prescription has worsened due to eye strain? I am puzzled as to why the measured prescription was 50 diopters lower than what I currently have in my glasses.
Why did the ophthalmologist recommend that I get new glasses?
If both of my eyes are -4.00 diopters, what would be the most suitable way to prescribe glasses? I primarily work in an office setting, using a computer, writing, reading, and engaging with electronic devices frequently.
How should I have my glasses prescribed to minimize eye strain?
Additionally, during the eye examination, my vision was tested first, and then after dilation, it was tested again.
Is there typically a difference between these two vision measurements? Should I base my new glasses prescription on the regular refraction or the one taken after dilation? I am concerned that if I switch from my current glasses, it might affect my eyes.
I fear that my myopia may worsen or that there could be other negative effects.

Lastly, I would like to ask about choosing sunglasses.
Is it better to opt for regular polarized sunglasses or those with electroplated mercury polarization? I have seen reports indicating that choosing the wrong sunglasses can be very harmful to the eyes.

Thank you once again for taking the time to answer my questions.

Lü Wu, 30~39 year old female. Ask Date: 2020/06/21

Dr. Gao Pilin reply Ophthalmology

Hello, Mr.
Lu:
When experiencing eye fatigue, the results of an eye examination may show a higher degree of myopia.
Therefore, if subsequent measurements indicate a lower degree, it is advisable to prescribe a lower prescription.
The degree measured after dilation should be the closest to the relaxed state of the eyes, which helps reduce strain and is better for eye health, making it less prone to fatigue.

If you spend long hours on the computer or reading, you might consider a pair of glasses with approximately 100 degrees less than your regular prescription.
If you prefer not to switch glasses frequently, multifocal lenses could be a suitable option.

For sunglasses, any that can block ultraviolet (UV) rays are acceptable.
Polarized and tinted lenses reduce brightness, depending on your needs.
Polarized lenses provide clearer vision in sunlight.
Avoid blue-tinted lenses.

At the E-Hospital in Puzi, Taiwan, the ophthalmology department is open on Monday, Tuesday, Thursday, and Friday mornings from 8:00 AM to 12:00 PM, and Wednesday afternoons from 2:00 PM to 4:30 PM.
Please note that online responses are for reference only; it is essential to seek medical attention at a healthcare facility if necessary.
I hope to have the opportunity to serve you.
Best regards,
Gao Pilin

Reply Date: 2020/06/21

More Info

When it comes to selecting the right prescription glasses and sunglasses, there are several important factors to consider, especially for individuals who spend a significant amount of time using computers or engaging in close-up work. Your concerns about your prescription and the potential for eye strain or worsening vision are valid and deserve careful consideration.

Understanding Your Prescription
Your current prescription indicates that you have one eye with a prescription of -3.50 (350 degrees) and the other at -4.00 (400 degrees). It’s not uncommon for prescriptions to vary slightly between different eye exams, especially if the examinations were conducted under different conditions or if your eyes were fatigued during the test. Factors such as prolonged screen time can lead to temporary changes in vision, which may cause your prescription to appear stronger than it actually is. This phenomenon is often referred to as "accommodative spasm," where the eye muscles become strained from overuse.

If your eye doctor suggested that your current glasses are too strong and contributing to early presbyopia (the gradual loss of the eye's ability to focus on nearby objects), it may be beneficial to follow their advice and get a new pair of glasses that better match your current needs.

Choosing the Right Glasses for Computer Use
For individuals who work extensively on computers or engage in activities that require prolonged focus on close objects, it is advisable to consider specialized lenses. Options include:
1. Single Vision Lenses: If your primary need is for distance or reading, single vision lenses can be tailored to your specific requirements.

2. Progressive Lenses: These lenses provide a gradual transition between different prescriptions, allowing for clear vision at various distances without the visible lines of bifocals.

3. Computer Glasses: These are specifically designed to reduce eye strain and improve comfort during prolonged screen time. They often have a slight magnification for reading and may include blue light filtering to reduce glare from screens.

Importance of Pupillary Distance (PD)
When ordering new glasses, ensure that your prescription includes your pupillary distance (PD), which is the distance between your pupils in millimeters. This measurement is crucial for proper lens alignment and optimal vision correction.

The Role of Dilation in Eye Exams
During an eye exam, your doctor may use dilation drops to widen your pupils, allowing for a better view of the internal structures of your eyes. The measurements taken after dilation can differ from those taken before, as your eyes are more relaxed and can provide a more accurate prescription. Therefore, it is generally recommended to use the measurements taken after dilation for your final prescription.

Choosing Sunglasses
When it comes to sunglasses, the choice between polarized lenses and those with a mirror coating (often referred to as "water mercury" lenses) depends on your specific needs:
- Polarized Sunglasses: These lenses reduce glare from reflective surfaces, making them ideal for outdoor activities like driving, fishing, or skiing. They enhance visual comfort and clarity.

- Mirror Coated Sunglasses: These lenses reflect light away from the eyes, reducing brightness. They can be beneficial in very bright conditions but do not necessarily provide the same glare reduction as polarized lenses.

It’s important to choose sunglasses that block 100% of UVA and UVB rays to protect your eyes from harmful radiation, which can contribute to conditions like cataracts and macular degeneration.

Conclusion
In summary, it is essential to have an up-to-date prescription that accurately reflects your visual needs, especially if you experience discomfort or strain while wearing your current glasses. Consider specialized lenses for computer use, and ensure that your new glasses are tailored to your lifestyle. When selecting sunglasses, prioritize UV protection and consider polarized lenses for enhanced visual comfort. If you have any ongoing concerns about your vision or eye health, consulting with an eye care professional is always the best course of action.

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