Types of Vision Correction Surgeries

 

Vision correction surgery is an ophthalmic procedure performed to achieve clear vision without glasses or contact lenses. It has steadily advanced over several decades. Modern vision correction techniques offer a variety of options tailored to each individual’s eye condition and lifestyle, with each method having its own advantages, limitations, and indications.

Because the structure and condition of the eyes vary greatly from person to person, no single procedure can be the best choice for everyone. Therefore, it is essential to undergo a thorough pre-operative examination to determine the most suitable option for each patient.

▲ Myopic regression caused by excessive regeneration of the corneal epithelium

Most patients are primarily concerned about how stable their vision will remain after surgery and the possibility of long-term side effects. In particular, many worry about myopic regression—a gradual decline in vision over time—which can vary depending on the condition of the cornea at the time of surgery, the type of procedure chosen, and post-operative lifestyle management.

The three major types of vision correction surgery are LASIK, LASEK, and SMILE. While their principles are similar, they differ in incision method, recovery process, and potential risk of complications.

▲ Myopic regression caused by deformation and displacement of the corneal epithelium

1. LASIK

LASIK is a procedure in which a thin flap is created on the surface of the cornea and lifted. An excimer laser is then applied to the underlying stromal layer to correct vision. Because the flap is repositioned afterward, epithelial regeneration is not required, resulting in a relatively rapid recovery. Most patients can return to daily activities as early as the following day, and the procedure involves minimal discomfort, making it suitable for office workers or those with busy schedules.

However, since creating the corneal flap involves an incision of a certain depth, LASIK may not be appropriate for patients with thin corneas or for individuals exposed to environments with a high risk of external trauma. The flap area can be vulnerable to strong physical forces, so those engaged in vigorous sports or occupations with a risk of eye injury should exercise caution. Temporary dry eye symptoms may occur immediately after surgery, so preoperative counseling and proper management are important.

▲ Corneal thickness changes after vision correction surgery

2. LASEK

LASEK is a procedure that does not involve creating a corneal flap. Instead, the corneal epithelium is gently loosened with an alcohol solution and removed, after which an excimer laser is applied to the stromal layer to correct vision. Since no flap is created, the cornea is more resistant to external trauma, and the procedure can be performed even on patients with thin corneas who are not suitable candidates for LASIK.

However, because the epithelium requires time to regenerate, recovery is slower than LASIK, and patients must wear a protective contact lens for the first few days. During this period, discomfort such as stinging, glare, or a foreign body sensation may occur. In rare cases, corneal haze can develop, although advances in surgical techniques and medication have significantly reduced its incidence. Owing to its structural stability, LASEK is often considered an appropriate option for soldiers, athletes, and individuals engaged in vigorous physical activities.

▲ Corneal tissue removal sites by type of laser vision correction surgery, with SMILE performed without removing the corneal epithelium

3. SMILE LASIK

SMILE LASIK is an advanced laser procedure that corrects vision through a minimally invasive incision. Using a femtosecond laser, a thin lenticule of tissue is created inside the cornea, which is then extracted through a micro-incision of about 2–4 mm, thereby altering the eye’s refractive power.

Because this method does not require the creation of a flap, it enhances the structural stability of the cornea. The small incision also makes the cornea more resistant to external trauma. In addition, the risk of postoperative dry eye is reduced, recovery is fast, and there is minimal discomfort. Since the corneal epithelium is not disturbed, complications related to epithelial healing and the risk of myopic regression are comparatively lower. However, there are still some technical limitations in correcting high astigmatism, and the procedure may not be suitable for certain eye structures.

4. Which surgery should I choose?

LASIK, LASEK, and SMILE are all proven safe and effective methods, but the most suitable option depends on each patient’s eye condition and lifestyle.

1. LASIK – for those who prioritize rapid recovery and comfort

2. LASEK – for patients with thin corneas or who need stronger resistance to external trauma

3. SMILE – for those who want reduced incision size and lower risk of complications

Postoperative lifestyle management is also essential. Excessive smartphone use, reading in poor lighting, or prolonged near work can negatively affect recovery and long-term vision stability. Regular eye examinations and healthy visual habits are crucial for maintaining results.

Vision correction surgery is not only about improving eyesight, but also about enhancing quality of life. It is recommended to carefully consider the differences among procedures, evaluate personal conditions, and make a decision after thorough consultation and detailed examination.