Is PRK Surgery Good for High Prescriptions?

If you’ve been told you have a high prescription and you’re exploring vision correction, you might be wondering whether PRK surgery is a safe and effective option for you. Many people with strong glasses or contact lens prescriptions worry that they may not qualify for laser eye surgery at all, especially if they’ve been discouraged from having LASIK due to corneal thickness or shape. It can feel frustrating when you want freedom from glasses, yet your prescription feels “too high” for the treatments you’ve heard about.

I’ve spoken to so many patients who come in thinking they’re no longer suitable for laser vision correction simply because of their prescription strength. The truth is, PRK can be an excellent option for many people with high prescriptions sometimes even better than LASIK for long-term eye health. PRK has been used safely for decades, and because it doesn’t involve creating a corneal flap, it preserves more tissue and works well for prescriptions that fall outside the LASIK range.

In this article, I’ll walk you through why PRK works so well for high prescriptions, what the suitability criteria are, what results you can realistically expect and when alternative treatments like SMILE or ICLs might be more appropriate. By the end, you’ll have a clear understanding of whether PRK is a good fit for your eyes and your visual goals.

What Counts as a “High” Prescription?

Before you can understand whether PRK is suitable, it helps to clarify what is considered a high prescription.

Generally accepted ranges:

  • Short-sightedness (myopia): –6.00D or higher
  • Long-sightedness (hyperopia): +4.00D or higher
  • Astigmatism: 3.00D or higher

Every clinic has their own criteria, but these ranges are widely used when assessing treatment suitability.

High prescriptions can still be treated, but the approach must be carefully planned.

Why PRK Is Often Recommended for High Prescriptions

PRK (Photorefractive Keratectomy) reshapes the cornea using an excimer laser, just like LASIK but without creating a flap. This difference offers several advantages for people with stronger prescriptions.

PRK preserves more corneal tissue

With a high prescription, the laser must remove more tissue to reshape the cornea.
PRK allows your surgeon to keep more tissue intact because it doesn’t require a flap.

Why this matters:

  • Your cornea stays stronger
  • You’re less likely to risk weakening the cornea
  • High corrections are safer when more tissue is preserved

This is one of the biggest reasons PRK is chosen for high prescriptions.

It’s safer for thin corneas

If you have a high prescription and thin corneas, LASIK might leave you with too little tissue remaining.
PRK removes this issue completely.

Many people who were told they’re “not suitable for laser eye surgery” end up being excellent PRK candidates.

No risk of flap complications

High prescriptions often benefit from the flap-free approach because:

  • There’s no flap to dislodge
  • No risk of rubbing issues
  • Less dryness after healing
  • Stronger corneal biomechanics

This makes PRK particularly appealing for people whose lifestyles involve risk of eye trauma (athletes, military personnel, trainers, etc.).

PRK results can be as good as LASIK for high prescriptions

People often worry that PRK won’t give the same clarity for high prescriptions but modern PRK techniques, wavefront technology and advanced lasers have made outcomes extremely reliable.

Most patients with high prescriptions experience:

  • Excellent long-term clarity
  • Stable vision
  • Significant reduction or complete removal of glasses dependency

The main difference is the recovery time, not the final result.

Is PRK Suitable for All Types of High Prescriptions?

Not always suitability depends on the exact numbers and the thickness of your cornea.
Let’s break it down.

High Myopia (–6.00 to –10.00+)

PRK can treat moderate to high levels of short-sightedness safely.

However, suitability depends on:

  • Your corneal thickness
  • Your corneal curvature
  • Pre-existing dryness
  • Stability of your prescription
  • Age
  • Whether you have any early signs of keratoconus

Some very high prescriptions may be better treated with ICLs (more on that later).

High Hyperopia (+4.00 to +6.00+)

Hyperopia requires more aggressive reshaping of the cornea.
PRK can treat some high hyperopic prescriptions, but LASIK often performs better in this range.

PRK may be suitable if:

  • Your cornea is too thin for LASIK
  • You have dryness that makes LASIK less suitable
  • You want to avoid flap risks

Your surgeon will evaluate which option gives the most predictable results.

High Astigmatism (3.00D–6.00D)

PRK can correct high astigmatism very effectively using modern wavefront and topography-guided lasers.

Suitability depends on:

  • Your astigmatism pattern
  • Whether your corneal shape is regular or irregular
  • Your corneal thickness
  • The stability of your prescription

Even astigmatism up to 6.00D is treatable in many cases.

How PRK Surgery Works for High Prescriptions

The procedure follows the same steps regardless of prescription, but the planning is more detailed for high numbers.

Step 1: Surface layer removal

The superficial layer (epithelium) is removed.

Step 2: Laser reshaping

The excimer laser reshapes the cornea precisely to correct your prescription.
For high corrections, this part is critical wavefront or topography-guided techniques are typically used.

Step 3: Bandage contact lens placement

A protective lens helps the epithelium heal over the next few days.

Step 4: Recovery and stabilisation

Because no flap is created, healing takes a little longer but results are just as sharp.

What Results Can You Expect With a High Prescription?

If you have a higher prescription, you’re probably wondering whether PRK can give you 20/20 vision.

The answer: For many people yes.

But results depend on:

  • Your corneal thickness
  • The amount of correction needed
  • Your age
  • Your eye health
  • Post-operative healing

General expectations:

  • 70–95% of high myopia patients achieve 20/20 or near 20/20
  • Hyperopia results are more variable
  • Astigmatism outcomes are excellent with modern lasers
  • Vision stabilises over 1–3 months
  • Long-term clarity is comparable to LASIK

The key difference is recovery speed.

PRK Recovery for High Prescriptions

If you have a high prescription, your recovery may be slightly slower but it remains safe and predictable.

Typical recovery timeline:

  • Day 1–3: Discomfort, tearing, blurry vision
  • Day 3–7: Bandage lens removed, basic clarity returns
  • Week 2–4: Functional vision for daily activities
  • Week 4–8: Good clarity
  • Month 3: Stable sharp vision
  • Month 6: Full refinement

High prescriptions may take a bit longer to stabilise, but the long-term results are worth it.

Advantages of PRK for High Prescriptions

Strong long-term corneal stability – This reduces future risks.

Lower risk of dry eye than LASIK – A strong benefit if you already suffer from dryness.

No flap complications – Especially beneficial for people with active lifestyles.

Compatible with thin or borderline corneas – This is often the deciding factor for high prescriptions.

Excellent visual outcomes – Modern PRK results rival LASIK for most patients.

Limitations of PRK for High Prescriptions

PRK is excellent, but it has limitations.

Longer recovery compared to LASIK

If you want instant clarity, PRK may not be ideal.

More discomfort during healing

The first few days can be uncomfortable, especially for higher corrections.

Less suitable for extremely high prescriptions

Very high prescriptions may require a different approach:

  • ICLs
  • RLE
  • LASIK (if thickness allows)
  • SMILE

Your surgeon will guide you based on safety.

When Is PRK Not Recommended for High Prescriptions?

There are specific situations where PRK may not be suitable.

Examples include:

  • Very thin corneas (below safe limits)
  • Early keratoconus
  • Unstable prescription
  • Significant scarring
  • Very high levels of myopia (–10.00D and above in some cases)
  • Very high hyperopia
  • Medical conditions affecting healing

In these situations, alternative treatments may be safer.

Alternatives to PRK for High Prescriptions

If PRK is not the best choice for your eyes, you still have options.

ICL Surgery (Implantable Collamer Lens)

Excellent for very high prescriptions.

Benefits:

  • No corneal tissue removed
  • Treats up to –20.00D myopia
  • Sharp, high-definition vision
  • Reversible and removable

ICL is often recommended when prescriptions exceed PRK limits.

SMILE Laser Surgery

Great for:

  • High myopia
  • Thick corneas
  • People wanting faster recovery

SMILE preserves more corneal strength than LASIK and avoids flap complications.

LASIK

Still a strong option if:

  • Your corneas are thick enough
  • You want rapid recovery
  • Your prescription is stable

LASIK often handles high hyperopia better than PRK.

Refractive Lens Exchange (RLE)

Best for:

  • People over 45
  • High hyperopia
  • Early lens changes
  • Presbyopia combined with high prescription

This offers permanent correction.

How to Know If PRK Is the Best Option for You

A detailed assessment with a refractive surgeon will answer this for you.

They will check:

  • Your corneal thickness
  • Your corneal shape
  • Your prescription stability
  • Your tear film
  • Your pupil size
  • Your lifestyle
  • Your long-term visual goals

With this information, they can recommend the safest and most effective treatment.

FAQs:

  1. Is PRK safe for people with high prescriptions?
    Yes, PRK is considered very safe for people with high prescriptions because it does not involve creating a corneal flap. This helps preserve more corneal tissue, which is especially important when a large correction is needed. Many patients who are not suitable for LASIK due to thin corneas or high numbers often find PRK to be a safe and reliable alternative that protects long-term corneal strength.
  2. Can PRK give me 20/20 vision if my prescription is very high?
    In many cases, yes. Most people with high myopia or high astigmatism achieve 20/20 or very close to it after PRK. Your exact result depends on factors like corneal thickness, overall eye health, and how well your eyes heal after the procedure. While hyperopia results can vary more, modern laser technology has greatly improved clarity for all types of high prescriptions.
  3. Is PRK painful if I have a high prescription?
    PRK itself is not painful because it is performed under anaesthetic eye drops that numb the surface. However, people with higher prescriptions may feel more discomfort during the first few days of healing. This usually includes watering, burning, and light sensitivity. These symptoms gradually reduce as the epithelium heals, and most people are comfortable within a week.
  4. Why does PRK recovery take longer for high prescriptions?
    Recovery takes longer because higher prescriptions require more corneal reshaping, and the surface layer of the eye needs additional time to regenerate. While LASIK gives quicker clarity, PRK builds sharpness gradually over weeks to months. The good news is that even though recovery is slower, the long-term clarity is just as good as LASIK for most people.
  5. Is PRK better than LASIK if I have thin corneas?
    Yes, PRK is often recommended when your corneas are thinner than what LASIK safely requires. Since PRK avoids making a flap, it preserves more tissue and keeps the cornea structurally stronger. Many people who are rejected for LASIK due to corneal thickness discover they are still excellent candidates for PRK.
  6. Can PRK treat very high astigmatism?
    Modern PRK can treat high levels of astigmatism extremely well. Technologies like wavefront-guided or topography-guided lasers allow precise reshaping of irregular curves. Success depends on whether your astigmatism is regular, stable, and coming from a healthy cornea. Many patients with astigmatism up to 6.00D see excellent improvements.
  7. How long does PRK healing take for high prescriptions?
    You can expect the first few days to be the most uncomfortable. By the end of the first week, you should regain basic clarity. Over the next few weeks, your vision becomes sharper and more stable, and most people feel satisfied with everyday clarity by one to two months. Final refinement can take up to six months, especially for higher prescriptions, but the improvement is gradual and steady.
  8. Is PRK a good choice if I have dry eyes?
    Yes, PRK is usually a better option than LASIK if you suffer from dryness. Because PRK does not create a flap or disturb as many corneal nerves, it reduces the risk of worsening dryness after surgery. Many people with pre-existing dry eye symptoms find PRK more comfortable during recovery and more suitable for long-term comfort.
  9. When is PRK not recommended for high prescriptions?
    PRK may not be suitable if your corneas are extremely thin, if you have unstable vision, early signs of keratoconus, significant corneal scarring, or a prescription that is beyond safe laser limits. In such situations, your surgeon may recommend safer alternatives such as ICL implantation, SMILE, or refractive lens exchange depending on your age and visual needs.
  10. What are the best alternatives if PRK cannot correct my high prescription?
    If PRK isn’t suitable, the next best option for very high numbers is usually ICL surgery, which works exceptionally well for high myopia without removing any corneal tissue. SMILE is also a great option for high myopia if your cornea is thick enough, offering quicker recovery. For people over 45 or those with high hyperopia, refractive lens exchange may be more effective because it treats both prescription errors and age-related focusing issues at the same time.

Final Thoughts: Is PRK the Right Choice for Your High Prescription?

Choosing the best vision correction treatment can feel challenging when you have a high prescription, especially if you’ve previously been told you’re not suitable for LASIK. PRK offers a strong, reliable alternative one that preserves more corneal tissue, avoids flap-related risks and provides excellent long-term clarity once healing is complete. For many people with stronger prescriptions, it remains one of the safest and most effective solutions available.

The most important step is getting a detailed assessment so your surgeon can determine which approach will give you the safest, most predictable results. Whether PRK, SMILE, ICLs or another option is ultimately recommended, the goal is to ensure your long-term vision is protected. If you’d like to find out whether PRK surgery in London is right for you, you can get in touch with us at Eye Clinic London to arrange a consultation and talk through your options.

References:

  1. Roszkowska, A. M., Tumminello, G., Licitra, C., Severo, A. A., Inferrera, L., Camellin, U., Schiano-Lomoriello, D. & Aragona, P. (2023) ‘One-Year results of photorefractive keratectomy for myopia and compound myopic astigmatism with 210 nm wavelength all-solid-state laser for refractive surgery’, Journal of Clinical Medicine, 12(13), p. 4311. Available at: https://www.mdpi.com/2077-0383/12/13/4311
  2. Curcă, P.F. (2024) ‘Advances in transepithelial photorefractive keratectomy (Trans-PRK): a comparative study of Trans-PRK vs FS-LASIK’, Diagnostics, 14(5), p. 481. Available at: https://www.mdpi.com/2075-4418/14/5/481
  3. Mifflin, M. et al. (2018) ‘High myopic photorefractive keratectomy outcomes with Alcon Wavelight EX500 excimer laser’, Clinical Ophthalmology, 12, pp. 1525-1531. Available at: PMC5995275. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5995275/
  4. Diakonis, V.F., et al. (2014) ‘Long-term follow-up of photorefractive keratectomy with intraoperative application of mitomycin C’, Journal of Cataract & Refractive Surgery, 40(10), pp. 1735-1741. Available at: PMC4020169. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4020169/
  5. Vestergaard, A.H., Ivarsen, A., Møller, H.T. & Hjortdal, J. (2013) ‘Long-term outcomes of photorefractive keratectomy for low to high myopia: 13 to 19 years of follow-up’, Journal of Refractive Surgery, 29(5), pp. 312-319. Available at: https://pubmed.ncbi.nlm.nih.gov/23659229/