As summer vacation and the holiday season get underway, more young people are planning vision correction surgery.
Recently, SMILE LASIK and SMILE Pro, which reduce dry eye symptoms and shorten recovery time, have become the preferred options.
But after deciding to have surgery and undergoing a detailed examination, some patients encounter an unexpected obstacle: a thin cornea.
Patients who have searched for information online beforehand often blame themselves if their corneal thickness falls below average, wondering, "Did I wear contact lenses for too long?" or "Did I take poor care of my eyes?"
To be clear, it is not their fault at all. Corneal thickness is determined almost entirely by genetics, like a map of the eye that is already set at birth. Being slightly thinner than others does not mean the eye is weak; it is simply an individual physical trait.
So why is corneal thickness so important in vision correction surgery? The cornea is a sturdy wall that withstands pressure inside the eye.
Vision correction surgery carefully reshapes that wall to adjust its refractive power. The key is not how much tissue is removed, but how much safe thickness remains after surgery. Even a thin cornea can be strong and healthy on its own, but when reshaping it, the skill of the medical team in preserving structural stability is what matters most.
The method used to reshape the cornea varies widely depending on the procedure. Traditional LASIK lifts a large section of the cornea to create a flap, while LASEK removes tissue from the surface. In both cases, damage to the upper corneal layer is unavoidable, raising concerns that the cornea may become less able to withstand external pressure after surgery. Standard SMILE LASIK, an alternative that emerged later, removes only an internal lenticule without peeling the surface, but it still requires an incision of about 2 to 4 mm, leaving some room for nerve damage.
This is where the value of 1 mm micro-incision SMILE becomes clear. It reduces the incision size of conventional SMILE surgery to just over 1 mm. For people with thin corneas, that tiny difference is more than a number; it is a lifelong safeguard.
Just as making a pinhole in taut paper preserves its overall tension better than punching a large hole, 1 mm SMILE Pro preserves the cornea's upper-layer structure as much as possible. Because the incision is extremely small, there is less damage to the sensory nerves that lead to the eye, significantly reducing dry eye symptoms and speeding up recovery. Above all, it helps maintain the cornea's structural strength, allowing technology to compensate for potential risks such as keratoconus, in which a weakened cornea bulges forward.
Of course, there are conservative cases in which, after a thorough examination, laser surgery itself is judged too risky. In such cases, a reliable alternative is phakic intraocular lens implantation, which does not alter the cornea at all and places a special lens inside the eye. It is also a safe solution for patients who previously underwent vision correction surgery, now have a thinner cornea, and need retreatment because of myopic regression.
Whether the cornea is thin from birth or there is too little residual cornea after repeat surgery, the solution should always put patient safety first. The standard for successful vision correction is not simply reaching 1.0 on the vision chart. What really matters is how healthy and safe the cornea remains long after surgery. That is why the 1 mm micro-incision technique in SMILE Pro and the insistence on strict safety standards are so important.
Courtesy of Kim Ji-seon, Director of Onnuri Smile Ophthalmic Clinic
