Laser subepithelial keratomileusis, LASEK in short,
as the name suggests is a laser-assisted surface
ablation surgery for vision correction. LASEK
is a close competitor of its two refractive surgery
counterparts of photorefractive keratectomy (PRK)
and laser in situ keratomileusis (LASIK). In
fact, LASEK came about as an attempt to improve
on laser surgical techniques.
All three procedures, however, are fairly
effective and consistent surgical techniques
for correcting myopia (nearshightedness) and
hyperopia (farsightedness) with or without
mild or moderate astigmatism.
The main indications for LASEK are:
- Thin corneas.
towards flap trauma especially related
to professional exposure (for instance
in the military) or lifestyles such as
contact sports etc.
- Mild myopia with a
lesser risk for subepithelial haze.
disorders (M/D/F changes).
- LASIK complications
in the contralateral eye.
astigmatism (corneal topographical
- Potential glaucoma cases.
LASEK contraindications include
fear of post-operative pain,
glaucoma, pregnancy and hyperopia
and hyperopic astigmatism.
Preoperative evaluation is vital to ensure
optimum results from any kind of laser surgery
for the eye. Clinical tests conducted for
LASEK are similar to that for the other refractive
surgical methods. These tests are:
visual acuity (UCVA).
- Best-corrected visual
- Manifest and cycloplegic
- Ocular dominance.
- Slit-lamp screening.
- Computerized videokeratography
The pre-surgical preparatory steps include:
of trimethoprim sulfate 1?mg/ml, polymyxin
B 10,000?U/ml or ciprofloxacin
to the eye thirty minutes before the
- Sterile dressing of the eye.
of one drop each of topical 0.5% proparacaine
and 4% tetracaine.
- Application of lid
Briefly, LASEK is a surgery that involves
three major steps:
- The creation of a hinged epithelial flap
by peeling the loosened epithelium as a sheet
(after treatment with 18% alcohol for 25
- Laser ablation.
- Replacement of the flap
over the ablated stroma.
Several surgical approaches are prevalent
with modifications here and there. Those proposed
by Camellin, Cimberle, Vinciguerra and Epstein]
have all reported effective results.
After the surgery, patients are advised to
take the following measures:
- Use of
oral analgesics but strictly when needed.
of tobramycin-dexamethasone ointment four
times a day for a week and
acetate 1% four times a day for 2 weeks.
of artificial tears when required.
Removal of the bandage contact lens generally
takes place after complete epithelial recovery,
generally on the 3th or 4th postoperative day.
Removal of the contact lens prior to that involves
the risk of detaching the epithelial flap along
with the contact lens.
Comparison with other refractive surgeries
In PRK, the central corneal epithelium is
detached and stromal tissue is removed from
the stromal bed with an excimer laser. In LASIK,
an epithelial–stromal flap is created
with a microkeratome, and a portion of the
stromal surface is removed with an excimer
laser. In LASEK, an epithelial flap is created
with the help of dilute ethanol and special
apparatus. Thereafter the stromal tissue is
removed from the stromal surface with an excimer
laser. Generally the epithelium in replaced
in LASEK. Sometimes when it is lost then the
process becomes almost identical to PRK.
Advantages of LASEK
It has been claimed that LASEK ensures faster
visual restoration, lesser postoperative discomfort
and lesser chances for haze than with PRK.
What’s more, theoretically LASIK-type
flap complications can be avoided with LASEK.
LASEK derives its basic benefits from the characteristics
of the epithelial sheet and its adhesion capability.
Complications with LASEK are generally similar
to those with PRK, although incidence of slow
epithelial recovery is higher in LASEK.
There have also been studies based on the
degree and type of errors. For instance, it
has been suggested that for patients with around
6-10 D myopia, LASIK is the preferred choice
over PRK or LASEK, considering consistency
of outcome and rate of vision rehabilitation.
It has also been advised that LASIK should
not be the choice in patients with thin corneas
(though there is a dispute among surgeons about
corneal thickness) and low-to-medium dry eyes.
In such cases, PRK or LASEK should be the preferred
The drawbacks of LASEK are as of now restricted
to research conducted on a very small population
because of its somewhat limited indications.
As of now, its primary disadvantages remain
its inconsistency in terms of postoperative
pain and epithelial recovery. But since postoperative
pain is a major problem of PRK, speedy epithelial
healing is vital for at least some degree of
postoperative relief to the patient. Though,
LASEK is said to address these issues, there
is not consistency in this regard.