How It Works?
LASEK (laser epithelial keratomileusis) is a relatively new variation of PRK, a procedure in which laser energy is applied directly to the eye’s outer surface for reshaping and vision correction.
To understand how LASEK works, you first must know the fundamental differences between LASIK, PRK and LASEK:
With LASIK, a thin flap is cut into the eye’s surface and then lifted. Laser energy is applied to the eye for reshaping, and the flap is replaced to serve as a type of natural bandage for quicker healing.
An eye surgeon using PRK does not cut a thin flap into the eye’s surface, as occurs with LASIK. Instead, laser energy is applied directly to the eye’s surface. The ultra thin, outer layer of the eye (epithelium) is removed completely by laser energy during a PRK procedure, and eventually grows back.
A LASEK procedure involves preserving the extremely thin epithelial layer by lifting it from the eye’s surface before laser energy is applied for reshaping. After the LASEK procedure, the epithelium is replaced on the eye’s surface.
In LASIK, the thicker flap is created with a the microkeratome cutting tool or a special laser. With LASEK, the ultra thin flap is created with a special cutting tool known as a trephine.
It is a new surgical procedure to treat myopia and able to reduce intraoperative and postoperative LASIK complications. The procedure was first described by M.C. (Mussimo Camellin, March 1999), In this technique, the ablated corneal surface is covered by full-thickness epithelium .This epithelial coverage modifies the wound-healing response of cornea, effectively protects the bare surface of the stroma and prevents the influx of inflammatory cells from tears, reducing the initial inflammatory change to the corneal stroma. The expression of TGF.β1 in the keratocytes is reported to be lower after LASEK than after PRK. This may result in less Postoperative haze and questionably less perioperative pain than PRK and more favorable visual outcomes . In addition, since no lamellar flap is created, LASEK may retain the biomechanical stability seen with PRK. Potential benefits over LASIK include elimination of flap complications and the ability to treat eyes with thinner corneas, larger pupils, and other anatomical features not amenable to LASIK treatment.
Advantages:
Causes less tendency toward dry eye with patients with borderline tear film.
Treats thin corneas with higher myopia successfully using newer scanning lasers.
Quicker recovery from neurotrophic cornea, post ablation.
Less risk of ectasia.
Simpler.
Better in patients with tight lids, abnormal anatomy, or very steep corneas.
Reduction of post operative pain?
Reduction of corneal haze.
Avoiding flap-related complications associated with LASIK.
Retainment of biomechanical stability of cornea.
Theoretical advantages
No flap-induced higher-order aberrations (ie, optics better)
Less long-term damage to corneal nerves
LASEK Disadvantages
1.Slower recovery, lack of predictability
Back to work: 3-5 days
Back to driving: 3-5 days
Back to recreational activities: 3-5 days
Full visual recovery takes one week to one month (author’s experience)
2.More pain
3.More anxiety for patient in recovery,
4.Epithelial defect for 2-4 days exposes eye to corneal ulcer risk
5.Re-treatments more difficult
6.More risk of haze
7.Recurrent erosion may be more likely.
According my experiences LASEK is a safe and effective technique with high predictability and stable visual outcomes to treat High Myopia, Myopic Astigmatism and Low Hyperopia.
Wavefront-Guided LASEK or Customized LASEK seems to be more effective and with higher predictability and patient satisfaction.
LASEK is used mostly for people with corneas that are too thin or too steep for LASIK, when it may be difficult to create a thicker LASIK flap. LASEK was developed to reduce the chance of complications that occur when the flap created during LASIK does not have the ideal thickness or diameter.
In LASEK, an ultra-thin flap is created on the eye’s surface, unlike the thicker flap in LASIK.
According to a survey of members of the American Society of Cataract and Refractive Surgery (ASCRS), the popularity of LASEK is growing among refractive eye surgeons, as it is with epi-LASIK – another variation of the procedure. Epi-LASIK uses a plastic blade, called an epithelial separator, to detach part of the epithelial layer from the eye.
However, eyes undergoing LASEK procedures generally heal more slowly and result in more complaints of discomfort than with LASIK. For this reason, some surgeons prefer to perform PRK rather than LASEK or epi-LASEK because they find no advantage in the latter procedures.
In fact, a 2008 study published in the Journal of Refractive Surgery indicated that people undergoing PRK tended to have less pain and healed slightly faster than people who had undergone a surgical technique called butterfly LASEK. “Butterfly” refers to the shape and type of thin flap lifted in LASEK, which is thought to increase comfort and healing time.
The LASEK Procedure
During LASEK, your surgeon uses local anesthesia. Then he or she cuts the epithelium, or outer layer of the cornea, with a fine blade (trephine). Then the surgeon covers the eye with a diluted alcohol solution for approximately 30 seconds, which loosens the edges of the epithelium.
After sponging the alcohol solution from the eye, the surgeon uses a tiny hoe to lift the edge of the epithelial flap and gently fold it back out of the way. Then he or she uses an excimer laser, which is used for LASIK or PRK, to sculpt the corneal tissue underneath. Afterward, the epithelial flap is placed back on the eye with a type of spatula.
After LASEK
In many ways, LASEK vision recovery is slower than LASIK recovery, but there are some differences. According to doctors who perform LASEK, the flap edge heals in about a day, though patients usually wear a bandage contact lens for approximately four days to protect the eye.
Vision recovery after LASEK may be slower than for other procedures, but there is less risk of complications such as dry eye.
Your eye may feel irritated during the first day or two afterward. Also, with LASEK compared with LASIK, it often takes longer to recover good vision – up to four to seven days – but this can vary from one person to the next. You also may experience more pain with LASEK compared with LASIK.
Talking to Your Doctor
If you are considering LASIK, but your doctor says you need LASEK, ask why. It’s not for everyone, but many surgeons who perform LASEK consider it a better option for some patients who will probably not do very well with LASIK. Also, in some studies LASEK has been associated with faster recovery of sensation or nerve function in the eye’s surface (cornea) compared with LASIK. It also may cause dry eye less frequently than LASIK.
However, keep in mind that a 2007 study published in the Journal of Cataract and Refractive Surgery concluded that the outcome of LASEK depends on the surgeon’s experience. Therefore, it’s always a good idea to ask how many procedures your surgeon has performed.