Illustration of laser eye surgery
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Comparing Types of Laser Eye Surgery: LASIK, PRK, LASEK, and SMILE Explained

Choosing the right type of laser eye surgery can be crucial for achieving better vision. In this article, we discuss the various types of laser eye surgery, comparing the leading methods—LASIK, PRK, LASEK, and SMILE—to help you understand the pros and cons of each and determine which might suit your specific vision needs.

Key Takeaways

  • Laser eye surgery, including LASIK, PRK (LASEK), and SMILE, utilises lasers to reshape the cornea to correct vision, with each type catering to specific vision issues and patient conditions.

  • LASIK is the most popular form of laser eye surgery, offering rapid recovery and effective vision correction for many. Still, alternative procedures like PRK, LASEK, and SMILE provide options for those with specific needs, such as thin corneas or a high risk of eye injury.

  • Choosing the right laser eye surgery depends on individual factors such as the stability of eye prescription, medical history, lifestyle, and potential side effects, with a thorough consultation and pre-operative evaluation being essential for successful outcomes.

Overview of Laser Eye Surgery

Illustration of laser eye surgery procedure

This procedure, often referred to as vision correction or refractive surgery, employs lasers to reshape the cornea, thereby improving sight. Its primary goal is to rectify sight issues, resulting in clearer and sharper vision.

Envision a world where you no longer depend on glasses or contact lenses, thanks to enhanced vision. This dream becomes a reality with laser eye surgery, also known as laser eye treatment.

Several laser eye surgery treatments are designed to address specific vision issues. The main types include LASIK, SMILE, and surface laser treatments such as PRK, LASEK, and TransPRK. Whether you’re short-sighted, long-sighted, or have astigmatism, there’s likely a laser eye surgery treatment option for you.

Wondering which one to choose? Let’s dive in and see which might be the most suitable option.

LASIK: The Popular Choice

Illustration of LASIK procedure

LASIK stands out among the various types of laser eye surgery. LASIK, which stands for laser-assisted in-situ keratomileusis, is a blade-free procedure that utilises a highly precise laser to reshape the cornea and enhance visual acuity. LASIK eye surgery enhances sight by reshaping the cornea with a laser.

It’s easy to see why LASIK has become a popular choice. With its versatility, minimal pain, and rapid recovery, most patients achieve 20/20 vision or better the day after surgery. Given its benefits, it’s unsurprising that LASIK ranks among the most-performed elective procedures worldwide.

However, LASIK is not a one-size-fits-all solution. Despite its effective treatment for a range of prescriptions, it’s unsuitable for individuals with thin corneas and less effective for those with severe short-sightedness.

Furthermore, post-surgery, patients should avoid certain activities like washing hair, entering steamy environments, participating in contact sports, and swimming during the early postoperative period. It is also important to protect your eyes with sunglasses. However, LASIK encompasses a variety of procedures customised to diverse needs, as we’ll discuss further.

Custom LASIK

Custom LASIK brings a new level of precision to the world of laser eye surgery. Unlike traditional LASIK, Custom LASIK utilises computer imaging to create a three-dimensional map of your eye for enhanced accuracy during the laser correction procedure.

This superior level of customisation enables the correction of each individual’s unique visual imperfections with a higher degree of precision, capable of measuring visual corrections to 0.01 Diopters compared to traditional LASIK’s 0.25 Diopters.

This innovative procedure can correct intricate visual defects like glares and reduced night vision, offering a truly personalised solution. There are four primary types of custom LASIK, namely:

  • Wavefront-optimised (perhaps the most commonly performed)
  • Wavefront-guided
  • Topography-guided
  • Ray tracing-guided (newest and currently only available on the WaveLight laser)

Each form is designed to rectify specific higher-order aberrations and corneal irregularities, making it highly adaptable to individual requirements.

The excimer laser used in LASIK (and PRK) is around 10 times more precise than the femtosecond laser used in SMILE (lenticule extraction). Because of this, custom treatments are NOT available with SMILE (as of the time of writing).

Clcik here to learn more about customised laser eye surgery procedures.

PRK: The Pioneer of Laser Eye Surgery

Illustration of PRK surgery

Before the advent of LASIK, PRK, or photorefractive keratectomy, was the primary method. It was first performed in the late 1980s. This pioneer of laser vision correction uses the excimer laser to reshape the cornea and correct refractive errors, making it a remarkably effective procedure for addressing longsightedness and astigmatism.

PRK paved the way for the multitude of laser eye surgeries available today, spearheading advancements in vision correction technology. However, it is still performed today and makes up around 10% of my practice.

However, PRK is less suitable for certain individuals and conditions. For example, it’s not recommended for pregnant or nursing women and those with certain conditions like diabetes, cataracts, or advanced glaucoma. In scenarios where other eye issues coexist, such as recurrent erosion syndrome, they can sometimes be addressed alongside vision correction, enhancing the appeal of PRK over alternative procedures.

Recovery and Aftercare

Recovery from PRK surgery typically involves using medicated eye drops and a protective bandage contact lens to facilitate corneal healing and manage discomfort. The healing period is longer than LASIK, often taking about five to seven days for the initial phase, verus 4-8 hours with LASIK. This combined with the postoperative pain makes PRK unattractive for many.

PRK is mainly reserved for those with thin or weaker corneas or who participate in activities where there is risk of eye injury, e.g. martial arts.

During recovery, patients may experience the following temporary difficulties:

  • Night vision

  • Driving

  • Glare

  • Halos

  • Ghost images

Dry eye syndrome is also a common complication following PRK, which is typically a temporary condition. Hence, routine check-ups are essential to oversee the healing process and handle potential complications.

LASEK: A PRK Variant

Illustration of LASEK surgery

LASEK surgery is a type of surface laser treatment that is adapted from PRK. It is also performed on the surface of the cornea without making a corneal flap.

Like PRK, it’s suitable for correcting nearsightedness, farsightedness, astigmatism, and is especially beneficial for individuals with thin corneas or those at an increased risk of facial injuries.

In LASEK, the cornea is accessed by dislodging the top layer using an alcohol solution, unlike LASIK which creates a corneal flap, or PRK which removes the epithelium.

Despite earlier claims of less pain and faster healing, repeated studies have shown no real difference from PRK. The final vision following LASEK is also identical to that with PRK.

LASEK was introduced partly to help reduce the incidence of a particular PRK complication known as haze.

Haze is a fine scar tissue formation just below the surface of the cornea. It occurs more commonly in high prescriptions, darker skinned individuals or regions with higher amounts of UV light.

However, the advent of mitomycin C (MMC), an anti-scarring topical drug applied at the time of PRK surgery, safely eliminates most incidences of haze and more efectively than LASEK. Hence, most surgeons who offer surface laser now use PRK with MMC.

Epi-LASIK

This laser vision correction procedure is a variant of LASEK. It creates a thin flap of cells from only the outermost layer of the cornea, known as the epithelium. The epithelium is replaced afterwards. There is no difference in healing, pain, recovery or results compared to PRK or LASEK.

It uses an epithelial separator with an oscillating blunt plastic blade. The plastic blade pushes the top skin layer back.

However, there is a significant risk of damage to the underlying collagen if any scar is present on the cornea, which is common in contact lens users. Because of this, I do not offer Epi-LASIK.

LASEK vs. LASIK

When comparing LASEK and LASIK, there are some key differences to note. While both procedures aim to correct vision errors by reshaping the cornea, the way they achieve this varies. LASEK exposes the cornea by dislodging the top layer using an alcohol solution, whereas LASIK creates a flap to access the corneal tissue.

   

LASEK

LASIK


Can treat all prescriptions

Prescription range *

Up to -12D (dioptres)

Up to -12D (dioptres)

Thin corneas

Fix astigmatism

Fast recovery


Post-op pain

Yes

No

Needs operating theatre

Infection rate

1 in 7,000

1 in 21,000

Recovery from LASEK surgery typically involves up to two weeks of healing, during which patients may experience moderate discomfort and light sensitivity. This is significantly longer than the recovery after LASIK, but similar in terms of post-operative care advice.

SMILE: A Different Route to the Same Result

Illustration of SMILE procedure

Finally, let’s examine SMILE, or Small Incision Lenticule Extraction. SMILE is a brand name from Carl Zeiss. The procedure is actually called lenticule extraction. Other brand names include:

  • SILK
  • CLEAR
  • SmartSight

This is a minimally invasive procedure that corrects refractive errors with minimal disruption to the epithelium. It uses a femtosecond laser to create a lenticule inside the cornea which is removed via a keyhole opening. Lenticule extraction offers benefits such as:

  • Reduced risks of post-surgery dry eye

  • Less impact on corneal nerves

Lenticule extraction surgery patients frequently notice improvements in vision by the next day although it can take several days to reach 20/20. Patients can typically resume regular activities within one to two days.

SMILE vs. LASIK

How does SMILE compare to LASIK? In contrast to what is often claimed, SMILE is not a less invasive procedure.

LASIK involves creating a corneal flap, whereas SMILE makes multiple cuts with the femtosecond laser followed by a keyhole incision under the corneal surface. The discomfort during recovery is not dissimilar.

Vision recovery is significantly slower with SMILE compared to LASIK. Most LASIK patients have good vision in 4-24 hours after treatment, compared to 1-7 days for SMILE.

   

SMILE

LASEK

Treat all prescriptions

Treat long-sight?

Prescription range *

Up to -10D (dioptres)

Up to -14D (dioptres)

Thinner corneas

Fix astigmatism

Astigmatism max D

5 dioptres

6 dioptres

Vision recovery

1-7 days

4-7 days


Post-op pain

No

Yes


Needs operating theatre

Infection rate

Yes, rate unknown

Rare = 1 in 7,000

A benefit of SMILE over LASIK is the lower risk of dry eyes during the first few months. This is likely due to the less extensive disruption of corneal nerves during the SMILE procedure. However, the degree of dryness is the same by 6-12 months following surgery.

Despite these differences, both procedures are brief, with the laser application itself lasting approximately 30 seconds per eye.

Factors to Consider When Choosing a Laser Eye Surgery

Given the multitude of laser eye surgery options, selecting the ideal one can seem daunting. Fear not – numerous factors can assist in guiding your decision.

One of the most important considerations is the stability of your eye prescription, which should ideally remain consistent for the past 12 months. This generally occurs after the age of 20 for most people, and can be later than 25 for some.

Your medical and ocular history, lifestyle habits, potential side effects, and financial considerations also play a crucial role in the decision-making process. Your eye specialist can help you decide on which procedure is right for you.

For example, individuals with a high risk of suffering an eye injury or whose occupations pose a danger of the corneal flap being dislodged might want to avoid LASIK and opt for SMILE or PRK.

On the other hand, those with a predisposition to dry eyes might find SMILE a more suitable option.

Consultation and Pre-Surgery Evaluation

In light of the complexities associated with selecting the appropriate laser eye surgery, a comprehensive consultation and pre-surgery evaluation are crucial. This detailed assessment ensures the correct laser eye surgery option is chosen for each individual, significantly impacting the success of the outcome.

During the initial screening consultation, various tests and scans are conducted to accurately assess your eye health.

The surgeon provides detailed information, ensuring an understanding of the laser eye surgery procedures and aiding in an informed decision-making process, including discussing alternative treatments if laser surgery is deemed unsuitable.

Summary

We’ve journeyed through the world of laser eye surgery, exploring the various procedures available.

From the popular LASIK and its custom variants, to the pioneering PRK or LASEK, and the more recent option SMILE (only for short-sight and astigmatism), each procedure offers unique benefits and potential drawbacks.

Choice of the right procedure depends on various factors, including the stability of your eye prescription, medical and ocular history, lifestyle habits, potential side effects, and financial considerations.

A thorough consultation and pre-surgery evaluation are crucial in making an informed decision. Remember, the path to enhanced vision is a personal journey, and the best choice is one that meets your unique needs and circumstances.

Frequently Asked Questions

Which type of laser eye surgery is best?

The best type of laser eye surgery is LASIK, which is the most commonly performed procedure with over 90% of suitable patients choosing this treatment.

What is the difference between LASIK and LASEK?

The main difference lies in the procedure: LASIK involves creating a corneal flap, while LASEK involves moving the top layer of the cornea. Both procedures have different recovery times, with LASEK taking about three to five days.

What is the most common laser surgery?

The most common laser surgery for vision correction is LASIK surgery. It involves using a laser to reshape the cornea and is a relatively painless procedure.

Is PRK better than LASIK?

If you’re active and prefer quicker results, LASIK might be a better choice. However, if you’re into contact sports or have thin corneas and dry eyes, PRK could be a better option due to its safety profile and long-term benefits.

What is Wavefront LASIK?

Wavefront LASIK uses computer imaging to create a detailed map of the patient’s eye, enhancing the accuracy of the laser correction procedure for improved precision in addressing complex visual defects.

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