Is Post-Laser Eye Surgery Vision Testing Accurate Without Dilation?

Q: Is Post-Laser Eye Surgery Vision Testing Accurate Without Dilation?

Hello： Is the measurement of refractive error using a phoropter accurate? Yes, it is accurate, but there may be some differences between machines. <br>Is it necessary to use a phoropter to check for cycloplegia for more accuracy? In adults, the difference after cycloplegia is rel

Is the vision test accurate after undergoing laser surgery?

Hello, Doctor.
I underwent laser surgery for high myopia about a year ago.
Recently, I went to another clinic (not the one that performed the laser surgery) for a refraction test, and they indicated that I still have myopia, which alarmed me.
I quickly returned to the surgeon who performed the laser procedure, and after an examination, they confirmed that I do not have myopia.
I would like to ask: Is the measurement using a phoropter accurate? Should a cycloplegic refraction be performed prior to the test for more accurate results? During the evaluation for laser surgery, they did use cycloplegic drops before the refraction, but during the post-operative check, they did not use cycloplegic drops, which raises my concerns about the accuracy of the measurements.
Thank you, Doctor.

Niming, 20~29 year old female. Ask Date: 2019/04/08

Dr. Gao Pilin reply Ophthalmology

Hello: Is the measurement of refractive error using a phoropter accurate? Yes, it is accurate, but there may be some differences between machines.
Is it necessary to use a phoropter to check for cycloplegia for more accuracy? In adults, the difference after cycloplegia is relatively minor.
The measurement obtained after cycloplegia reflects the refractive error when your ciliary muscle is completely relaxed.
As for comparing refractive errors, it is more meaningful to compare them at the same reference point, such as comparing measurements taken after cycloplegia.

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Gao Pi-Lin

Reply Date: 2019/04/08

More Info

Post-laser eye surgery vision testing can indeed raise questions about accuracy, especially when dilation is not performed. After undergoing laser surgery, such as LASIK, patients often experience changes in their vision that can lead to confusion regarding their refractive status.
To address your concerns, let's first discuss the accuracy of vision testing using a refractometer without dilation. Generally, a refractometer can provide a reliable measurement of your refractive error, but it is important to note that the results can vary based on several factors, including the specific equipment used and the condition of your eyes at the time of testing. In many cases, especially in adults, the difference in measurements obtained with and without dilation may not be significant. However, dilation allows for a more comprehensive assessment by relaxing the ciliary muscle, which controls the lens's shape and can affect the measurement of refractive error.

When you underwent the pre-operative evaluation for laser surgery, dilation was performed to ensure an accurate assessment of your refractive error. This is crucial because it provides a baseline measurement when the eye is in a relaxed state. Post-surgery, if dilation was not performed during your follow-up vision testing, it could lead to discrepancies in the measurements. If the eye is still in a state of accommodation (the ability of the eye to focus on near objects), it may not reflect the true refractive error accurately.

If you received conflicting results from different clinics, it is advisable to return to your original surgeon or a trusted ophthalmologist who is familiar with your surgical history. They can perform a comprehensive examination, potentially including dilation, to clarify your current refractive status.
In addition, it is essential to consider that after laser surgery, some patients may experience temporary fluctuations in vision as the eyes heal. This healing process can take several months, and during this time, vision may not stabilize immediately. Therefore, it is not uncommon for patients to experience variations in their vision during the recovery phase.

If you are concerned about the possibility of residual myopia (nearsightedness) or other refractive errors, it may be beneficial to undergo a thorough examination that includes both subjective and objective refraction tests. This approach can help determine whether any residual refractive error exists and whether corrective measures, such as glasses or enhancement procedures, may be necessary.

In summary, while vision testing without dilation can provide useful information, it may not always be fully accurate, especially in the context of recent laser eye surgery. Dilation can enhance the accuracy of refractive measurements by allowing the eye to relax completely. If you have concerns about your vision post-surgery, it is best to consult with your surgeon or a qualified eye care professional who can provide a comprehensive evaluation and address any lingering questions or issues.

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