Lasek

The Lasek procedure (synonyms: laser subepithelial keratectomy, laser epithelial keratomileusis, laser-assisted subepithelial keratectomy) is a surgical technique used in ophthalmology (eye care) to correct a refractive anomaly (myopia or Hypermetropia – nearsightedness and farsightedness), in which a thin layer of tissue, the corneal epithelium (upper layer of the cornea), is selectively removed and an optimization of the visual acuity (visual ability of the eye) is subsequently achieved with the help of a laser. Myopia correction is possible up to – 8 dpt (diopters; measure of the refractive power of the eye) and hypermetropia correction is possible up to 4 dpt.

Indications (areas of application)

• Astigmatism – aberration in the human eye that leads to a reduction in visual acuity.
• Myopia – defective vision, which can be based on both an elongation of the bulb (eyeball) and increased refractive power of the front parts of the eye – myopia correction is up to – 8 dpt.
• Hypermetropia – defective vision resulting from a change in the length of the bulb. However, unlike myopia, in this case the bulb is shortened, so that the relationship between refractive power and bulb length results in reduced vision – hypermetropia correction is up to 4 dpt.
• Activities with increased risk of trauma (eg, police officers and martial artists) is the use of the Lasek advantageous

Contraindications

• Glaucoma (glaucoma; increase in intraocular pressure).
• Diabetic retinopathy – retinal disease caused by diabetes mellitus; deterioration of vision to blindness.
• Cataract (cataract; clouding of the lens).
• Collagenoses (group of connective tissue diseases caused by autoimmune processes) – systemic lupus erythematosus (SLE), polymyositis (PM) or dermatomyositis (DM), Sjögren’s syndrome (Sj), scleroderma (SSc) and Sharp’s syndrome (“mixed connective tissue disease”, MCTD).
• Rheumatic diseases (often based on a disorder and impairment of the immune system).
• Cardiac pacemaker

The surgical procedure

The Lasek method is a further development of PRK (photorefractive keratectomy; treatment for the elimination of a defective vision by means of removal of the epithelium of the cornea and laser use) and has an important diagnostic significance in those patients in whom, due to insufficient corneal thickness, LASIK (laser in situ keratomileusis; a similar laser procedure to Lasek, with the difference that in LASIK a flap (thin corneal disc) is cut out and “folded over” and a correction (laser ablation) of the underlying corneal tissue is performed with the help of an ophthalmic laser) would be too risky. It follows that the gentle Lasek method corrects the dioptric number (refractive power) in the central area of the superficial cornea. In summary, it can be emphasized that the Lasek method combines the advantages of LASIK and PRK. About the surgical procedure:

• At the beginning of the procedure, the cornea is anesthetized with eye drops so that analgesia (prevention of pain sensation) is achieved.
• In the following step, the epithelium of the cornea already mentioned above is incised circularly with a microtepan, then dissolved by adding 20% alcohol and moved to the side by using a spatula. Thus, the preparation of the corneal surface when using the Lasek method is different from the LASIK method.
• After completion of the preparation, the modeling of the cornea is now performed. For this purpose, the excimer laser (this generates electromagnetic radiation used for surgical treatment of refractive anomalies), which provides myopia and hypermetropia correction on the principle of changing the corneal curvature by ablating the superficial layer of the cornea with the aim of improving visual acuity. The state-of-the-art eye-tracking system (method of tracking the patient’s gaze) provides the surgeon with the opportunity to respond to involuntary eye movements what causes that the result of the procedure is not negatively affected.
• Following this step, a rearrangement of the epithelium of the cornea, previously displaced to the side, is performed and carefully smoothed by the attending physician.
• Lasek method requires the use of a bandage lens (special contact lens to ensure the healing process) for up to 5 days after the procedure.

Possible complications

• Haze formation (haze on the cornea).
• Pain in the wound healing phase
• Delay in wound healing

Benefit

Lasek technology is becoming increasingly important in eye surgery:

• Lasek technique is a highly precise method of correcting refractive anomalies.
• Compared to LASIK, no “flap complications” are expected, which causes a decision in favor of the Lasek method in case of increased risk of trauma (occupation, sports).Note: Without flap* , there is only a small risk of infection.
• Compared to PRK (photorefractive keratectomy), the Lasek technique is much less painful (when the anesthesia wears off several hours after the procedure).
• The procedure only slightly dependent on the thickness of the patient’s cornea.
• In case of non-optimal course, a post-correction is feasible by repeating the procedure.
• In people with sicca syndrome (autoimmune disease with, among other things, keratoconjunctivitis sicca, which leads to permanently dry eyes) the risk of keratitis (corneal inflammation) is minimized.

* Corneal flap cut in the top layer of the cornea in conventional LASIK and femto-LASIK.