What is Laser Eye Surgery?

Understanding Laser Eye Surgery and Refractive Error Correction

Laser eye surgery serves as an umbrella term for various surgical procedures designed to correct refractive errors, which fundamentally alter how the eye focuses light. The primary objective of these interventions is to reshape the cornea to improve visual acuity. The most prevalent types of laser eye surgery performed today include LASIK, PRK, LASEK, and Epi-LASIK.

While each of these four procedures utilizes a specialized excimer laser to reshape corneal tissue, they differ significantly in their surgical approach. Variations exist in the specific techniques used, recovery timelines, surgical instruments required, and individual patient candidacy. For instance, a patient with specific ocular characteristics might be a more suitable candidate for PRK than for LASIK.

Selecting the Optimal Laser Eye Surgery Procedure

A qualified ophthalmologist determines the most appropriate procedure through a comprehensive, specialized eye examination. The surgeon’s recommendation is based on achieving the best possible visual outcome for the patient's unique eye structure. It is important to note that most patients achieve 20/20 vision or better following a successful laser eye surgery.

1. LASIK (Laser in Situ Keratomileusis)

LASIK is currently the most common laser eye surgery performed worldwide. The procedure begins with the creation of a thin corneal flap using either a mechanical blade or a laser. Many surgeons prefer the laser method for its high precision and lower risk of visually significant complications, though all-laser LASIK typically involves a higher cost. Once the flap is retracted, the excimer laser reshapes the underlying cornea to correct the refractive error.

2. PRK (Photorefractive Keratectomy)

As the second most common procedure, PRK involves removing a portion of the corneal surface or epithelial tissue. Because no flap is created, the removed tissue naturally grows back during recovery. PRK eye surgery is often preferred by patients who wish to avoid a corneal flap or those with thin corneas who are not ideal candidates for LASIK. The same excimer laser technology is used to reshape the cornea once the epithelium is removed.

3. LASEK (Laser Epithelial Keratomileusis)

LASEK shares similarities with both LASIK and PRK. The procedure starts with the application of alcohol to the corneal epithelium to loosen the outermost cells. This allows the surgeon to move the cells aside without removing them entirely. After the excimer laser reshapes the stroma, the epithelial sheet is replaced, and a bandage contact lens is applied to facilitate healing. This method is often a viable option for patients with thin corneas.

4. Epi-LASIK (Epithelial Laser in Situ Keratomileusis)

Epi-LASIK is frequently considered a hybrid of LASIK and LASEK. In this procedure, a very thin flap consisting only of epithelial tissue is created and moved aside. The surgeon then uses the excimer laser to reshape the stroma. The epithelial flap is subsequently replaced and covered with a contact-lens bandage. Some surgeons favor Epi-LASIK because the flap is limited to the epithelial layer and the procedure avoids the use of alcohol.

Comparison of Laser Eye Surgery Types

The Historical Evolution of Laser Eye Technology

The foundations of laser eye surgery were laid in the 1980s at an IBM research facility. Researchers discovered that an excimer laser could precisely incise animal tissue without leaving scar tissue. This breakthrough led to the first application of lasers on human tissue. Ophthalmologists were among the first medical professionals to collaborate with researchers to adapt this technology for vision correction.

Following a decade of clinical trials and technical refinements, procedures like LASIK and PRK received global regulatory approvals. By the year 2001, LASIK had established itself as the most common elective surgery in the world.

Candidacy and Age Requirements

Laser eye surgery is generally recommended for individuals aged 18 or older, as the eye can continue to change during adolescence. Key requirements for candidacy include:

• A documented record of stable vision for at least one year (some providers require two years).
• Meeting specific physiological criteria determined during a clinical exam.
• Absence of contraindications that would affect healing.

Only a trained professional can accurately determine your candidacy and recommend the specific procedure that aligns with your ocular health needs.

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Op. Dr. Ahmet UMAY
Bristol University
Ophthalmology Section / UK

Reference:
www.lasik.com UK