Are all laser eye surgery procedures the same? Exploring LASIK, PRK, TransPRK and SMILE
This week’s blog on LASIK procedures and if they are all the same, has been contributed by Dr Osama Giledi, Consultant Ophthalmologist, Specialist in Cataract, Cornea and Refractive Vision Correction Surgery
If you are considering laser eye surgery, it is natural to feel overwhelmed by the number of procedure names you may encounter. Terms such as LASIK, PRK, and SMILE are often used interchangeably, which can make it difficult to understand how they differ and which option may be most appropriate for you.
All laser eye surgery procedures are different, and no single technique is suitable for everyone. They vary in the technology used, the surgical approach, and the healing process. Suitability also depends on individual factors such as prescription range, corneal thickness overall eye health and lifestyle needs. This blog outlines the main types of laser vision correction, explains how they differ, and highlights why careful clinical assessment, rather than choosing a procedure based on name or cost, is central to achieving safe and effective outcomes.
WHAT IS LASER VISION CORRECTION?
Laser vision correction is a group of procedures used to treat refractive errors, which occur when the shape of the eye prevents light from focusing clearly on the retina. Common refractive errors include short-sightedness (myopia), long-sightedness (hyperopia), and astigmatism.
These procedures work by precisely reshaping the cornea (the clear front surface of the eye), so that light entering the eye is focused more accurately onto the retina, and this can eliminate the need for glasses or contact lenses.
Broadly, laser vision correction procedures fall into three main categories:
- Surface laser procedures, where the corneal surface is treated without creating a flap
- LASIK-based procedures, which involve creating a corneal flap before reshaping the underlying tissue
- SMILE Procedures, a newer technique that uses a minimally invasive, flap-free approach that reshapes the cornea from within
While many people are suitable for laser vision correction, eligibility depends on individual eye health and visual stability. In general, suitable candidates tend to have a stable prescription, healthy eyes, and realistic expectations about outcomes. A comprehensive assessment is the only way to determine if you are suitable and the best treatment option that suits your visual needs.
LASIK BASED PROCEDURES
LASIK (Laser-Assisted In Situ Keratomileusis) is one of the most well-established laser eye surgery procedures. During LASIK, a thin corneal flap is created and gently lifted, allowing an excimer laser to reshape the underlying corneal tissue. The flap is then repositioned, where it naturally adheres as the eye heals.
Blade (microkeratome) LASIK
An older method that uses a mechanical blade to create the corneal flap. Today, it is largely replaced by femtosecond laser technology, which allows for greater accuracy, consistency, and safety.
Femto (Blade-Free) LASIK
Femto LASIK uses a femtosecond laser to create the corneal flap instead of a blade. This allows greater precision and consistency, with the ability to tailor flap thickness, size, and position based on individual eye measurements. Improved control over flap creation may reduce the risk of certain flap-related complications and contribute to more predictable healing and visual outcomes.
Recovery following LASIK is often relatively quick with many people noticing improvement within a short period. However, recovery experiences can vary, and visual outcomes continue to stabilise over time as the eye heals.
SURFACE LASER PROCEDURES: PRK AND TransPRK
Surface laser procedures reshape the cornea without creating a corneal flap. Instead, the surface layer of the cornea (the epithelium) is removed or displaced before laser treatment is applied to reshape the underlying tissue.
PRK (Photorefractive Keratectomy)
PRK is one of the earliest laser vision correction techniques and still remains a very valuable option with new laser machine today. During PRK, the outer corneal layer is removed, and the laser reshapes the corneal surface directly. The surface layer then regenerates naturally during healing.
PRK is often recommended for:
- patients with thinner corneas
- individuals at higher risk of eye trauma
- those unsuitable for flap-based and SMILE procedures
TransPRK
TransPRK is a laser-based form of surface treatment in which both removal of the corneal surface layer and vision correction are performed using the laser, without direct contact from surgical instruments.
This approach can offer:
- improved comfort compared to traditional PRK
- enhanced precision
- reduced variability
Recovery following surface laser procedures typically takes longer than with LASIK, about one to 2 weeks and some discomfort is expected during the early healing phase. However, as healing progresses, visual outcomes can continue to improve and, in the longer term, may be comparable for appropriately selected patients.
SMILE: A MINIMALLY INVASIVE ALTERNATIVE
SMILE (Small Incision Lenticule Extraction) is a laser vision correction technique that reshapes the cornea without creating a corneal flap and does not use an excimer laser.
During SMILE, a femtosecond laser is used to create a small, lens-shaped piece of tissue (known as a lenticule) within the cornea. This lenticule is then removed through a small incision, altering the corneal shape to correct vision.
SMILE may be more suitable for selected patients, particularly those with:
- very short-sightedness (myopia)
- specific corneal measurements and characteristics
- Dry eyes
- Concerns with flap such as contact sport
Because SMILE does not involve lifting a corneal flap and preserves more of the corneal surface structure, it may be associated with less disruption to corneal nerves. This can be a consideration for some individuals, including those with a tendency towards dry eye. However, SMILE is not suitable for all prescriptions, degrees of astigmatism, or eye shapes, and suitability must always be determined through comprehensive clinical assessment.
Recovery following SMILE is often as fast as LASIK procedures, and painless with many individuals noticing huge improvement after a few hours from the treatment.
UNDERSTANDING RISKS AND LIMITATIONS
All forms of laser vision correction carry potential risks and limitations. These may include dry eye symptoms, glare, or halos, under- or over-correction, and variations in visual recovery. The likelihood of these effects varies depending on the procedure performed and individual eye characteristics and is discussed in detail during the clinical assessment.
As for recovery, timelines can affect everyday activities differently depending on the procedure and individual healing response. Returning to work, driving, exercise, or screen use may take varying amounts of time, and personalised guidance is provided as part of post-treatment care.
WHY THERE IS NO “BEST” LASER EYE PROCEDURE
It is common for people considering laser eye surgery to ask, “Which procedure is the best?”
In practice, a more appropriate question is “Which procedure is most suitable for my eyes?
Each laser vision correction technique has specific strengths and some limitations. The safest and most effective option depends on a range of individual factors, including:
- corneal thickness, shape, and stability
- type and stability of refractive error
- tear film quality and ocular surface health
- lifestyle, occupation, and visual demands
- risk factors for eye injury
- personal preferences regarding recovery and comfort
Suitability is determined through a detailed clinical assessment, during which a laser eye surgery specialist evaluates individual eye characteristics and visual needs to recommend the most appropriate procedure. This approach ensures that the chosen treatment prioritises visual outcomes, safety, and long-term eye health.
WHAT IF YOU ARE NOT SUITABLE FOR LASER VISION CORRECTION?
Laser vision correction is not suitable for everyone. Factors such as very thin corneas, very high refractive prescriptions, certain corneal conditions, or significant dry eyes can limit whether laser-based procedures are appropriate. In such individuals, insertion of lens inside the eye (Phakic implant such as ICL) or refractive lens-based surgery may be considered as an excellent alternative option
During the clinical assessment, the specialist will determine whether laser vision correction or refractive lens-based surgery is the most appropriate and safest option, based on individual eye health, visual needs, and long-term considerations.
THE IMPORTANCE OF A COMPREHENSIVE ASSESSMENT
A comprehensive pre-operative assessment is a critical part of laser vision correction and alternative options. It involves detailed evaluation of corneal structure, tear film quality, retinal health, and individual visual needs to determine whether treatment is appropriate and, if so, which approach is most suitable.
Assessment helps to:
- guide appropriate procedure selection
- reduce the risk of complications
- support long-term visual satisfaction
At Moorfields Eye Hospital Dubai, this careful, individualised approach underpins all refractive treatments, allowing patients to make informed decisions based on a clear understanding of their suitability and treatment options.
CONCLUSION
As outlined above, laser eye surgery includes several distinct techniques, each designed to address different eye characteristics and visual needs. Procedures such as LASIK, PRK, TransPRK, and SMILE vary in how they are performed, how recovery progresses, and who they may be suitable for. In some cases, phakic Implant ( ICL ) or refractive lens-based surgery may offer a more appropriate alternative.
Understanding these differences, together with the findings of a comprehensive clinical assessment, is key to making an informed decision. When procedure selection is guided by specialist evaluation and individual suitability, patients are better positioned to pursue safe and effective vision correction based on long-term eye health rather than procedure names or cost alone.
FREQUENTLY ASKED QUESTIONS (FAQs)
1. Is one laser eye procedure safer than the others?
Safety depends on how well a procedure matches your individual eye anatomy, prescription, tear film health, and lifestyle. A technique that is suitable for one person may not be appropriate for another. The safest approach is a comprehensive clinical assessment to identify which procedure offers the most appropriate for you.
2. Does SMILE replace LASIK?
SMILE is an alternative option for selected patients, particularly those with certain types of short-sightedness. It does not replace LASIK or surface laser procedures. Each technique addresses vision correction in a different way and has its own advantages and limitations. LASIK, PRK, TransPRK, and SMILE all remain valuable options, depending on individual suitability.
3. Is laser eye surgery painful?
Laser eye surgery is performed using numbing eye drops, so the procedure itself is not painful. Sensations during recovery vary depending on the technique used. Surface laser procedures are typically associated with more discomfort during the early healing phase, while other procedures may involve milder symptoms. Pain management and aftercare are discussed as part of the assessment and follow-up process.
4. Can laser eye surgery correct astigmatism?
Laser eye surgery can correct astigmatism in many cases. The ability to do so depends on the degree and type of astigmatism, as well as corneal shape and thickness. Some procedures are better suited to correcting certain patterns of astigmatism than others. A detailed assessment helps determine whether laser treatment is appropriate and which technique would be most effective.
5. Will I still need glasses later in life?
Laser eye surgery corrects your current refractive error, but it does not prevent natural age-related changes in the eye. Most people will eventually experience presbyopia, which affects near vision, typically from the mid-40s onwards. This means that reading glasses may still be needed later in life, even after successful laser vision correction.
6. Is laser eye surgery permanent?
The corneal reshaping achieved through laser eye surgery is permanent. However, the eyes continue to age naturally. Changes such as presbyopia or lens-related conditions can still occur over time and may affect vision. While the correction itself remains stable, future visual needs can evolve as part of the normal ageing process.
7. Can dry eye affect eligibility?
Tear film quality and ocular surface health are important factors when assessing suitability for laser eye surgery. Existing dry eye does not automatically rule out treatment, but it may influence the choice of procedure or require treatment before surgery. Addressing dry eye first helps improve comfort, healing, and overall outcomes.