LASIK (Laser-Assisted in situ Keratomileusis) is a popular refractive eye surgery that uses lasers to reshape the cornea and correct vision problems like nearsightedness, farsightedness and astigmatism. But LASIK is not recommended for everyone, especially those with high prescriptions outside the treatable range.
What is the maximum myopia prescription for LASIK?
Most LASIK providers consider -10.00 diopters to be the maximum myopia prescription that can be safely and effectively treated with LASIK. This corresponds to a nearsighted prescription of -10.00 diopters.
Going beyond -10.00D of myopia starts to pose challenges for achieving good visual outcomes with LASIK:
- Higher risk of postoperative visual aberrations and quality issues
- Less predictable results
- Higher enhancement rates
- Increased risk of ectasia (cornea instability and bulging)
That said, there are some exceptions where highly experienced LASIK surgeons may consider treating prescriptions up to around -12.00D in very selective cases. But in general, -10.00D is considered the maximum myopic prescription most surgeons will treat with LASIK.
What is the maximum hyperopia prescription for LASIK?
For farsightedness (hyperopia), the general consensus is +6.00 diopters is the maximum prescription that can be safely treated with LASIK.
Prescriptions above +6.00D start running into similar limitations as high myopia, including:
- Less predictable results
- Higher retreatment rates
- Difficulty achieving full correction in one treatment
- Higher risk of visual quality issues like glares and halos
Most reputable LASIK surgeons will limit hyperopic treatment to +6.00D, except in rare cases with extremely thin corneas where a lower limit of +5.00D may be advised.
What is the maximum astigmatism prescription for LASIK?
For correcting astigmatism, most LASIK providers follow these maximum treatment guidelines:
- Up to 6.00 diopters of astigmatism can be treated along with myopia or hyperopia
- Standalone astigmatism treatment is usually limited to around 4.00D
Higher cylinders create a greater disparity in corneal curves, making treatment more challenging. Above 6.00D of astigmatism, most surgeons recommend alternative procedures like PRK or ICL surgery rather than LASIK.
How is the maximum prescription limit determined?
There are a few key factors that determine the maximum LASIK prescription that can be safely treated:
- Corneal thickness – A thicker cornea provides more tissue to work with for reshaping by the laser. Thinner corneas have less flexibility and structural stability.
- Pupil size – Larger pupils are more prone to visual side effects from corneal reshaping like halos and glares.
- Age – Younger corneas are more stable. Older patients have higher risk of ectasia.
- Pre-existing conditions – Certain diseases like diabetes and autoimmune conditions increase postoperative risks.
- Corneal topography – Irregular corneal maps pose extra challenges.
By assessing these factors, the surgeon determines the maximum amount of correction the individual cornea can safely tolerate to optimize visual outcomes.
What risks are there with LASIK for high prescriptions?
Some of the main risks associated with LASIK treatment of high prescriptions include:
- Under/over-correction – Difficulty achieving full prescription correction, requiring enhancement surgery.
- Loss of best corrected visual acuity – Worse vision even with glasses after LASIK.
- Visual distortions – Halos, glares, starbursts, ghosting around lights.
- Corneal ectasia – Weakened cornea that bulges and becomes increasingly unstable.
- Dry eyes – Chronic dryness and irritation.
The risk profile increases sharply for prescriptions over the recommended LASIK limits. That’s why it’s crucial to choose an experienced surgeon for any high correction case.
What are the alternatives to LASIK for high prescriptions?
For patients exceeding the safe range for LASIK, there are several alternative vision correction options to consider instead, including:
- PRK – Surface laser eye surgery with similar results to LASIK. slower recovery but often better for high prescriptions.
- ICLs – Implantable collamer lenses placed inside the eye.
- Toric ICLs – Version of ICLs that also corrects astigmatism.
- Phakic IOLs – Similar concept as ICLs but uses rigid lens material.
- RK/AK – Incisional techniques like radial keratotomy and arcuate keratotomy.
- CRI – Corneal relaxing incisions to treat astigmatism.
- Corneal rings – Segments implanted in the cornea to change its shape.
- Cataract surgery – Replacing cloudy lens with prescriptive IOL.
An experienced refractive surgeon can help determine which option may be best for your individual circumstances.
How do I know if I’m candidate for LASIK with a high prescription?
If you have a high nearsighted, farsighted or astigmatism prescription, the best way to determine if you’re a LASIK candidate is to schedule exams and a consultation with an experienced LASIK surgeon.
The surgeon will conduct detailed screening and measurements of your eyes to assess if your corneas are within the acceptable range for LASIK treatment, including:
- Corneal thickness mapping
- Corneal topography
- Wavefront analysis
- Pupil size in dim light
- Schirmer’s test for dry eyes
Based on the results the surgeon can advise if your eyes are suitable for LASIK or if an alternative procedure would be safer and provide better outcomes.
It’s very important to get an evaluation from an expert LASIK surgeon before considering any procedure. Self-screening or screening from an optometrist is not enough to determine candidacy, particularly with high prescriptions. The LASIK surgeon has the necessary experience and diagnostic technology to thoroughly examine your specific case.
What should I look for in a LASIK provider for high prescriptions?
When seeking LASIK with a high prescription, it’s essential to find an experienced, reputable provider with the necessary expertise and resources to treat higher-risk cases. Important credentials to look for include:
- Extensive experience with high myopic and hyperopic LASIK procedures.
- Onsite diagnostic technology like Pentacam rotating Scheimpflug camera.
- Proven safety record and thousands of successful procedures completed.
- Custom LASIK capabilities for personalized treatment.
- Advanced laser systems designed to treat high prescriptions.
- Availability of alternative procedures like PRK and ICLs onsite.
Reputable LASIK chains that screen carefully and only treat prescriptions within safe limits are preferable to “discount” LASIK providers that will treat any range of prescriptions.
The provider should use the latest diagnostic technology to carefully evaluate your corneas and explain the risks and benefits of your particular case. Beware of providers who seem quick to rush into treatment without thorough preoperative testing.
Can I get monovision LASIK with a high prescription?
Monovision LASIK corrects one eye for distance vision and one for near vision as a means of treating presbyopia for patients needing reading glasses. However, monovision becomes more challenging with higher prescriptions.
Most surgeons will not recommend monovision LASIK for prescriptions over:
- Myopia over -6.00D
- Hyperopia over +4.00D
- Astigmatism over 4.00D
At higher prescriptions, the blurriness induced in one eye from monovision becomes problematic. Alternative options for presbyopia correction with high myopia or hyperopia include:
- ICL surgery with mutlifocal lenses
- Toric ICLs
- Reading glasses
- Blended vision contact lenses
Monovision can still be successfully achieved with higher astigmatism as long as myopic and hyperopic prescription are moderate.
Conclusion
The maximum LASIK prescription depends on factors like the amount of myopia, hyperopia and astigmatism as well as corneal health and thickness. Most surgeons follow guidelines of treating up to -10.00D of myopia, +6.00D of hyperopia and 6.00D of astigmatism. Prescriptions outside these ranges require careful evaluation for safety and alternatives like PRK or phakic IOLs may be preferable over LASIK in many high prescription cases.