What are the different types of laser eye surgery, including LASIK (Laser-Assisted In Situ Keratomileusis), available in Korea?

Types of Laser Eye Surgery Available in Korea

The main types of laser eye surgery available in Korea include LASIK (Laser-Assisted In Situ Keratomileusis), PRK (Photorefractive Keratectomy), LASEK (Laser Subepithelial Keratomileusis), Epi-LASIK, and SMILE (Small-Incision Lenticule Extraction). 1

LASIK (Laser-Assisted In Situ Keratomileusis)

LASIK is one of the most commonly performed laser refractive procedures in Korea. It involves:

• Creating a hinged flap consisting of corneal epithelium, Bowman layer, and superficial stroma
• Reflecting the flap manually
• Using an excimer laser to reshape the exposed corneal stroma
• Repositioning the flap

The flap can be created using either:

• Mechanical microkeratomes
• Femtosecond lasers (which can be programmed to vary flap diameter, depth, hinge width, and side-cut angles) 1

LASIK provides:

• Rapid visual recovery
• Minimal postoperative pain
• Good predictability for vision correction 2

Surface Ablation Techniques

PRK (Photorefractive Keratectomy)

PRK involves:

• Removal of the central corneal epithelium (can be done mechanically, chemically, or by laser)
• Direct ablation of the Bowman layer and superficial corneal stroma using an excimer laser
• Application of a bandage contact lens until re-epithelialization occurs

PRK may be preferred for patients with thin corneas or when LASIK is contraindicated. 1

LASEK (Laser Subepithelial Keratomileusis)

LASEK is a modification of PRK that attempts to preserve the epithelium:

• Dilute ethanol alcohol is applied to loosen the corneal epithelium
• An epithelial trephine and spatula are used to score, loosen, and roll up the epithelium (which remains attached at a hinge)
• Laser ablation is performed
• The epithelium is unrolled back over the corneal stroma
• A bandage contact lens is applied until healing occurs 1, 3

LASEK may be suitable for patients with:

• Small palpebral fissures
• Deep-set eyes
• Corneal basement membrane dystrophy
• Extremely steep or flat corneas
• Thin corneas or high myopia
• Higher risk of corneal trauma due to occupation or recreational activities 3

Epi-LASIK

Epi-LASIK is an alternative to LASEK:

• Instead of using alcohol, an epikeratome (with a blunt oscillating separator) is used to dissect an epithelial sheet from the Bowman layer
• Laser ablation is performed
• The epithelial sheet is either replaced or discarded 1

SMILE (Small-Incision Lenticule Extraction)

SMILE is a newer technique available in Korea:

• An intrastromal lenticule is created with a femtosecond laser in a shape corresponding to the desired refractive correction
• The lenticule is accessed and removed by the surgeon through a small opening incision
• FDA-approved for myopia between -1.00 D and -8.00 D with astigmatism ≤-0.50 D 1

Comparative Outcomes

When comparing these procedures:

1. Visual Recovery and Pain:

   • LASIK offers faster visual recovery and less postoperative pain compared to surface ablation techniques 2
   • PRK, LASEK, and Epi-LASIK have similar postoperative pain profiles 4

2. Efficacy and Stability:

   • For high myopia, LASIK has shown superior results in visual predictability compared to LASEK 5
   • Surface ablation techniques may show more myopic regression over time compared to LASIK 6

3. Complications:

   • Surface ablation techniques have a higher incidence of corneal haze 6
   • LASIK has specific flap-related complications that are avoided with surface ablation techniques 3

Important Considerations

1. Potential complications of laser refractive surgery include:

   • Visual aberrations (glare, halos, especially at night)
   • Decreased contrast sensitivity
   • Induced astigmatism
   • Dry eye symptoms
   • Corneal haze or scarring
   • Loss of best-corrected visual acuity 1

2. Contraindications include:

   • Unstable refraction
   • Abnormal corneal topography/tomography (e.g., keratoconus)
   • Insufficient corneal thickness
   • Visually significant cataract
   • Uncontrolled glaucoma or external disease 1

3. Patient satisfaction depends on both expectations and surgical outcomes. The most frequent complaints from dissatisfied patients include blurred vision, glare, dry eyes, and night-vision problems. 1

The selection of the most appropriate procedure should be based on corneal thickness, degree of refractive error, corneal topography, and patient-specific factors such as occupation and lifestyle.