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Mr David Allamby
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LASEK Procedure Explained
LASEK, also commonly referred to as PRK, is a surface laser eye surgery procedure used to correct short-sight, long-sight and astigmatism. Unlike LASIK, it does not involve creating a corneal flap. The entire treatment is done on the surface of the cornea.
PRK was the original form of laser eye surgery, first performed in 1987 by Dr Theo Seiler in Germany. During treatment, the thin surface skin layer of the cornea, called the epithelium, is removed so that an excimer laser can precisely reshape the collagen tissue underneath. Reshaping the cornea changes how light focuses on the retina, which corrects your prescription. The surface skin layer then grows back naturally over the following days as the eye heals.
LASEK (PRK) is still performed today, 30 years after the introduction of surface laser treatment.
For a broader overview of the treatment and expected results, see our LASEK/PRK eye surgery page. To learn whether surface laser treatment may be suitable for you, read our LASEK eligibility guide.
How Does LASEK Work?
LASEK uses a combination of a laser and gentle surgical preparation of the corneal surface to reshape the cornea and improve sight. [1] [2]
PRK and LASEK are essentially the same type of surface laser procedure. Both let an excimer laser reshape the cornea without creating the corneal flap used in LASIK. The only real difference is how the surface skin is handled. Traditionally, LASEK involved loosening the epithelial layer, usually with a dilute alcohol solution applied for a few seconds, then easing it aside and replacing it after laser treatment. With PRK, that same layer is simply removed and allowed to grow back naturally.
Most surgeons now use a PRK approach. The reason is the use of mitomycin C (MMC), which prevents haze (a fine layer of scar tissue) from forming just below the corneal surface. MMC is applied briefly during the procedure. It is highly effective at preventing haze without replacing the epithelium, reducing the overall risk by around 80%. [3] The epithelium also grows back smoother and more quickly when the original layer has been removed, as in PRK, rather than repositioned.
LASEK and PRK at a glance |
|---|
Around five minutes per eye |
Both eyes usually treated at the same appointment |
Anaesthetic drops used to numb the surface |
No corneal flap |
Microscopic amounts of corneal tissue removed by the excimer laser |
A temporary bandage contact lens fitted at the end |
How the laser reshapes the cornea. The excimer laser is considered a cool ultraviolet laser. It does not burn or heat the eye. Each pulse breaks the molecular bonds in an extremely thin layer of tissue and removes it, a process called photoablation, working to a fraction of the thickness of a human hair with each pass.
Because there is no heat, the tissue around the treatment zone is left undisturbed. The laser removes only microscopic amounts of tissue to change the curvature of the cornea, flattening it a little to correct short-sight, steepening it for long-sight, or smoothing an irregular curve to correct astigmatism.
The technology at Focus
Focus is an Alcon-named Centre of Excellence and a European training centre for ray-tracing-guided LASIK, LASEK and PRK. [4] [5] [6] Your treatment is planned in fine detail from a high-resolution 3D model of your own eye and programmed into the laser before you lie down.
During treatment, the WaveLight EX500 excimer laser delivers 500 pulses a second, and a high-speed eye tracker checks your eye position over 1,000 times a second, repositioning the beam faster than the eye can move. [7] That keeps the treatment precisely centred even if you make tiny involuntary movements, so you don't have to hold your eye perfectly still.
What Happens During LASEK Surgery?
Although the treatment itself is quick, several stages are involved in preparing the eye, reshaping the cornea and protecting its surface afterwards. Here is what happens, step by step.
1. Your Eye Is Numbed
A local anaesthetic is applied as eye drops to numb the surface thoroughly. There are no needles or injections. The drops may sting for a second or two, then the surface goes numb within 20-30 seconds. This means you are fully awake during the procedure, but you should not feel pain. The drops' effect is longer than the procedure itself, so they will keep the eye numb throughout.
2. Your Eye Is Prepared for Treatment
You will lie back on the laser bed while your eye is positioned under the laser. A small, soft instrument called a speculum is used to hold the eyelids gently apart, so you do not have to think about blinking during the procedure. Only one eye is treated at a time, and the other eye is kept covered. You will be asked to look at a coloured blinking fixation light, which helps keep your eye aligned with the laser. It is normal to feel some pressure or a sensation of the eye being washed with fluid at this stage.
3. The Surface Layer of the Cornea Is Removed
The thin epithelial surface layer is removed so the laser can reach the corneal tissue underneath. In PRK, this layer is gently lifted away after applying a dilute alcohol solution, typically with a soft brush or blunt instrument, or with a brief pass of the laser itself. In classic LASEK, the same layer is loosened with alcohol and eased to one side. Either way it takes only a few seconds, and because the eye is numb it is not painful. The layer isn't needed for reshaping and regrows naturally afterwards in 3-5 days.
4. The Excimer Laser Reshapes the Cornea
This is the part that corrects your vision. Your individual treatment plan, calculated from your scans, is already programmed into the laser. You keep looking at the fixation light while the excimer laser removes microscopically thin layers of tissue to reshape the cornea and change how light focuses inside the eye. You will hear a soft ticking or buzzing sound as the laser fires and may notice a faint smell. The eye tracker follows every small movement, and if your eye moves too far, the laser simply pauses and waits. The laser is active for only a few seconds, roughly two seconds or so for each dioptre of your prescription, so even a strong correction is over quickly. For most treatments, MMC is then applied to the surface for a short time to keep the cornea clear as it heals.
5. A Protective Contact Lens Is Applied
Once the cornea has been reshaped, a temporary bandage contact lens is placed over the eye. This protects the regenerating epithelial surface while it heals and helps reduce discomfort in the early days. Bandage contact lenses are routinely used following surface procedures such as PRK and LASEK to assist epithelial healing and reduce discomfort (EyeWiki/AAO). You are given antibiotic and anti-inflammatory eye drops, plus lubricating drops, to use while the surface heals. [8] The second eye is then treated in the same way.
How Long Does PRK or LASEK Surgery Take?
The excimer laser is active for only a small part of the procedure, roughly two seconds or so per dioptre of correction, so the actual laser time is usually just a few seconds per eye. Including numbing the eye, preparing the surface, the laser treatment and placing the bandage lens, the treatment itself takes around 10 to 12 minutes for both eyes. Your overall appointment is longer than this, because your eyes are checked before and after treatment. You will also receive instructions on how to care for your eyes after treatment and how to use your drops.
What Does LASEK Feel Like?
Anaesthetic eye drops numb the surface of the eye before treatment, so the procedure itself should not normally be painful. You may still notice a mild pressure, a feeling of the eye being touched or washed, and the bright fixation light while your eye is being prepared and treated.
You do not need to consciously keep your eye open or hold it still. The speculum holds the eyelids apart for you, and the laser's high-speed eye tracker follows the position of your eye and keeps the treatment centred as the cornea is treated. You cannot feel the excimer laser pulses as they reshape the cornea.
Any discomfort is usually more noticeable in the first few days after LASEK or PRK than during the procedure itself, because the surface layer needs time to grow back. For more information about possible side effects and complications associated with surface laser treatment, see our LASEK Safety and Risks Guide.
What Happens After LASEK Surgery?
As soon as treatment is finished, the bandage contact lens is already in place, and your drops have been started. Your vision will be blurred at first, and the eye may become more uncomfortable or light-sensitive once the anaesthetic wears off. You will not be able to drive yourself home after treatment, so you will need someone to collect you.
Your vision will be hazy and may worsen during the first 2-3 days as the skin layer on the front of your eye grows. Your vision will start to improve after you remove the bandage contact lens, as blinking helps smooth the new surface skin.
This page focuses on the procedure itself. For the healing timeline, pain management, returning to work, driving, exercise and other postoperative precautions, see our LASEK Surgery Recovery and Aftercare Guide.
Book a FREE Consultation
Considering LASEK eye surgery? Book a free telephone consultation and speak to one of our expert eye surgeons to see if LASEK surgery is right for you.
LASEK Procedure FAQs
Focus Clinic, London. These LASEK answers are written and reviewed by our chief surgeon, Mr David Allamby MD, who has performed more than 30,000 laser eye surgery procedures over 25 years. Focus is an Alcon-named Centre of Excellence and European training centre for ray-tracing-guided LASIK.
Anaesthetic eye drops numb the eye, so patients should not feel pain during laser treatment. You may feel pressure or a sensation of the eye being touched, but not pain. Surface laser procedures can, however, cause discomfort during the first few days afterwards while the epithelial layer grows back, which is why a bandage lens and drops are used.
You do not need to worry about keeping your eye open or still yourself. A small, soft eyelid holder keeps the eyelids apart during treatment. The laser also has a high-speed eye tracker that checks your eye position over 1,000 times a second and repositions the beam to match, so small movements don't affect the result. If your eye moves too far, the laser pauses automatically until you are lined up again.
The laser itself is active for only a few seconds per eye, roughly two seconds or so per dioptre of correction. So a -3.00 dioptre correction would take about 6-7 seconds. That's very fast! Including preparation with anaesthetic drops, the whole treatment only takes around five minutes per eye. Your overall appointment is longer because your eyes are prepared and checked before and after treatment.
Yes. LASEK and PRK are usually performed on both eyes during the same treatment session. Each eye is treated separately, one after the other. In the early days of PRK (during the 1990s), each eye was treated separately at a different visit. With better pain management and more accurate treatment, it is now possible to treat both eyes on the same day.
You will be awake during LASEK and will usually be asked to look towards a coloured fixation light while the laser is working. Your vision may become blurred or hazy at different points, and you may see soft, shifting lights of various colours, but you will not see the laser reshaping the cornea itself. If you're worried about seeing sharp instruments near your eye, you can relax. You will not be able to see anything in clear detail during the procedure, and no sharp instruments are involved.
A temporary bandage contact lens protects the corneal surface while the epithelial layer grows back. It supports surface healing and helps reduce discomfort during the early recovery period. Bandage contact lenses are routinely applied after LASEK and PRK. Unlike your normal contact lenses, they have no refractive power and just provide a smooth cover over your cornea.
The temporary bandage contact lens stays on the eye while the epithelial surface heals. It is normally removed at a follow-up appointment 3-5 days after surgery. One of our specialist optometrists will check your eye and remove the bandage contact lens once they are satisfied that the surface has healed sufficiently.
References
Numbered in order of appearance in the text.
1. Bastawrous A, Silvester A, Batterbury M. Laser refractive eye surgery. BMJ. 2011;342:d2345. doi:10.1136/bmj.d2345
2. Murueta-Goyena A, Cañadas P. Visual outcomes and management after corneal refractive surgery: a review. J Optom. 2018;11(2):121-129. doi:10.1016/j.optom.2017.09.002
3. Chang YM, Liang CM, Weng TH, Chien KH, Lee CH. Mitomycin C for the prevention of corneal haze in photorefractive keratectomy: a meta-analysis and trial sequential analysis. Acta Ophthalmol. 2021;99(6):652-662. doi:10.1111/aos.14704
4. He G, Bala C. Ray-tracing-guided myopic LASIK: real-world clinical outcomes. J Cataract Refract Surg. 2023;49(11):1140-1146. doi:10.1097/j.jcrs.0000000000001286
5. Kanellopoulos AJ. Ray-tracing customization in myopic and myopic astigmatism LASIK treatments: 2-year visual function and psychometric value outcomes. Clin Ophthalmol. 2024;18:565-574. doi:10.2147/OPTH.S444174
6. Alcon. WaveLight Plus personalised (ray-tracing) refractive technology. https://www.myalcon.com/international/professional/refractive/wavelight-plus/
7. US Food and Drug Administration. WaveLight EX500 Excimer Laser System Procedure Manual. https://www.accessdata.fda.gov/cdrh_docs/pdf2/P020050S043C.pdf
8. Steigleman WA, Rose-Nussbaumer J, Al-Mohtaseb Z, et al. Management of Pain after Photorefractive Keratectomy: A Report by the American Academy of Ophthalmology. Ophthalmology. 2023;130(1):87-98. doi:10.1016/j.ophtha.2022.07.028
Why Choose Us?
100% 20/20 vision
Focus Clinic has a remarkable 100% success rate for 20/20 vision. We know of no other clinic that has matched these results. There is a big difference between, for example, 98% and 100% success, especially if you are in the 2%.
10 year guarantee
Your 10 Year Guarantee means you can return at any time if you have additional questions on the quality of your vision. If you have distance vision correction for short-sight then any repeat laser eye treatments to correct a return of myopia in the first 10 years are included free of charge.*
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*Terms and conditions apply, excludes any age-related changes and conditions unrelated to the primary treatment
* 100% 20/20 success is from our peer-reviewed published results for LASIK binocular vision treating short-sight up to -6.00 dioptres including up to 2.00 dioptres of astigmatism.
**J Cataract Refract Surg. 2023 Nov 1;49(11):1140-1146. Ray-tracing-guided myopic LASIK: real-world clinical outcomes. George He, Chandra Bala
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