High Myopia: Key Questions on Measurement and Treatment - Ophthalmology

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High myopia, also known as pathological myopia, is a condition where the eye elongates excessively, leading to a refractive error that can significantly impact vision. Understanding its measurement and treatment is crucial for managing the condition effectively. Here are answers to your key questions regarding high myopia:
1. Does high intraocular pressure affect the measurement of myopia?
Yes, elevated intraocular pressure (IOP) can potentially influence the accuracy of refractive measurements. High IOP can lead to changes in the shape of the cornea and the overall eye structure, which may result in inaccurate readings when using devices like autorefractors or keratometers. Therefore, it is essential to manage IOP effectively before conducting precise refractive assessments.

2. Can wearing contact lenses all day affect the next day's measurements?
Absolutely. Wearing contact lenses, especially soft lenses, can temporarily alter the shape of the cornea due to the pressure exerted by the lens. This change can lead to a different refractive measurement the following day. It is generally recommended to remove contact lenses for a certain period (often overnight) before undergoing refractive measurements to ensure accuracy.

3. If a SMILE laser procedure is performed on a patient with a measurement of -1000 degrees, will there still be residual myopia?
The SMILE (Small Incision Lenticule Extraction) laser procedure is designed to correct high levels of myopia effectively. However, the outcome can vary based on individual factors such as corneal thickness, the degree of myopia, and the precision of the surgical technique. While many patients achieve excellent vision post-surgery, some may still have a small degree of residual myopia. It is essential to have a thorough pre-operative assessment to discuss expectations and potential outcomes.

4. Is the measurement taken after using a cycloplegic agent the standard refraction?
Yes, measurements taken after instilling a cycloplegic agent (which temporarily paralyzes the ciliary muscle) are considered more reliable for determining the true refractive error. This is particularly important in children and individuals with high myopia, as it helps eliminate the influence of accommodation on the measurement. Even if contact lenses were worn the previous day, the cycloplegic refraction provides a clearer picture of the eye's refractive status.

5. Can cataract surgery address high myopia, and does prior laser surgery affect this?
Cataract surgery can indeed correct refractive errors, including high myopia, by replacing the cloudy lens with an intraocular lens (IOL) that is calculated to provide the desired refractive outcome. However, if a patient has undergone laser surgery (like LASIK or SMILE) prior to cataract surgery, it may complicate the calculation of the appropriate IOL power. The corneal shape and thickness can be altered by previous laser procedures, which can affect the accuracy of IOL power calculations. Therefore, it is crucial to inform the cataract surgeon about any previous refractive surgeries to ensure the best possible outcome.

In summary, managing high myopia involves careful consideration of various factors, including intraocular pressure, the impact of contact lenses, and the implications of previous surgeries. Regular follow-ups with an eye care professional are essential for monitoring the condition and determining the most appropriate treatment options. If you have further questions or concerns, it is advisable to consult with an ophthalmologist who specializes in refractive surgery and myopia management.