Myopia Measurements: Which Prescription is More Accurate?

Q: Myopia Measurements: Which Prescription is More Accurate?

Hello： 1. <br>According to the information you provided, the data for the left eye during the dilated ophthalmic refraction was 650, while the data from the manual refraction at the optical store was 675. <br>For the right eye, the dilated ophthalmic refraction data was 575, and

Myopia degree

1.
I had a dilated eye exam at the ophthalmologist, which showed my left eye as -6.50 and my right eye as -5.75.
However, when I went to the optical shop for a manual refraction, it showed -6.75 for the left eye and -6.00 for the right eye.
Which measurement is more accurate?
2.
Will wearing glasses with a prescription of -2.25 have any effects?

Xiao Xi, 20~29 year old female. Ask Date: 2023/05/19

Dr. Gao Pilin reply Ophthalmology

Hello: 1.
According to the information you provided, the data for the left eye during the dilated ophthalmic refraction was 650, while the data from the manual refraction at the optical store was 675.
For the right eye, the dilated ophthalmic refraction data was 575, and the manual refraction at the optical store was 600.
There is no significant difference between these two sets of data, but the prescription after dilation may be more suitable.
2.
Wearing glasses with an additional 25 degrees has little impact.
There are no issues with adaptation.

Reply Date: 2023/05/19

More Info

When it comes to understanding myopia measurements and determining which prescription is more accurate, there are several factors to consider. The two sets of measurements you provided come from different sources: one from an ophthalmologist using a cycloplegic refraction (with dilation) and the other from an optician using a non-cycloplegic method.
1. Understanding the Measurements:
- The first set of measurements (left eye: -6.50 D, right eye: -5.75 D) was taken after dilating your pupils. This method allows for a more accurate assessment of your refractive error because it temporarily paralyzes the ciliary muscle, preventing it from affecting the measurement. This is particularly important in cases of myopia, as the ciliary muscle can cause fluctuations in the readings.

- The second set of measurements (left eye: -6.75 D, right eye: -6.00 D) was taken without dilation. Non-cycloplegic refraction can sometimes yield different results, especially if the patient is accommodating (focusing) during the test. This can lead to underestimating the degree of myopia.

Given these considerations, the measurements taken during the cycloplegic refraction (the first set) are generally regarded as more accurate for determining the true refractive error of the eyes. Therefore, the prescription from your eye doctor (-6.50 D for the left eye and -5.75 D for the right eye) is likely the more reliable one.

2. Impact of Wearing Glasses with Different Prescriptions:
- Wearing glasses with a prescription that is not aligned with your true refractive error can lead to discomfort and visual disturbances. In your case, wearing glasses that are stronger than your actual prescription (like -6.75 D for the left eye when your true prescription is -6.50 D) may cause strain, headaches, or blurred vision. Conversely, wearing glasses that are weaker than your prescription can lead to eye strain as your eyes work harder to focus.

- The additional 0.25 D difference in prescription may not seem significant, but it can still have an impact, especially if you wear these glasses for extended periods. It is essential to have a prescription that closely matches your needs to ensure comfort and optimal vision.

3. Recommendations:
- It is advisable to follow up with your eye care provider to discuss your measurements and any symptoms you may be experiencing. If you feel discomfort with the current prescription, it may be worth considering a new pair of glasses based on the cycloplegic refraction results.

- If you have any concerns about your vision or the accuracy of your prescription, don't hesitate to seek a second opinion or request a re-evaluation from an eye care professional.

In conclusion, the cycloplegic refraction results are typically more accurate for determining your true refractive error. Wearing glasses that do not match your prescription can lead to discomfort and visual issues, so it is essential to ensure your glasses are based on the most accurate measurements available.

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