What is LASIK Surgery?

lasik surgery

The first eyeglasses were developed in the 13th century and Leonardo Da Vinci imagined a precursor to the contact lens in 1508, but, despite hundreds of years of development, neither glasses nor contacts are a perfect solution for imperfect eyesight.


Surgery intended for vision correction, called refractive surgery, has long been seen as a way to escape the inherent limitations of the appliance-based approach, but it had to await significant advances in technology before it began to fulfil its promise. The great breakthrough in refractive surgery came with the application of the laser to eye surgery in the 1980s.

Today, the most common refractive surgery is laser-assisted in situ keratomileusis, or LASIK, which can be used to treat nearsightedness, farsightedness and astigmatism. Those problems all involve the cornea, the transparent outer layer at the front of the eye that is largely responsible for the ability to focus. Regardless of the specific defect it addresses, LASIK works by reshaping the cornea so that it can function properly.

LASIK surgery is done on an outpatient basis under local anesthesia. Before surgery, the size and shape of the corneas are precisely measured with specialized instruments, so that the eye surgeon can plan the procedure based on the patient’s unique corneal topography. For the operation, the eye is numbed with anesthetic drops and the patient may receive a mild sedative. The surgeon then applies a suction ring to immobilize the eye.

The next step is to create a flap in the outer layer of the cornea, a procedure that can be done in two ways. In traditional LASIK surgery, the surgeon uses a precision mechanical cutting instrument called a microkeratome. In bladeless or all-laser LASIK, the surgeon uses a special femtosecond laser to create the flap. Both methods can achieve excellent results.

In either case, a hinge is left at one end of the flap and the flap is folded back, exposing the middle layer of the cornea. The surgeon then uses a different laser, the excimer laser, to reshape the cornea in accordance with the detailed measurements obtained prior to surgery. With the aid of a computerized tracking system, the excimer laser vaporizes infinitesimal amounts of precisely targeted corneal tissue, leaving adjacent tissue untouched.

Once the corneal reshaping is complete, the hinged flap is repositioned and it will naturally reattach to the underlying tissue. Follow-up care is usually limited to a course of antibiotics, the use of eye drops and instructions to rest and avoid rubbing the eyes.

Many patients experience an immediate improvement in vision, some experience a more gradual progression and the vast majority report that they are satisfied with their results. However, LASIK, like any surgical procedure, can be followed by post-operative complications. Chronically dry eyes are the most common symptom, but there can also be infection, visual abnormalities and problems with the corneal flap. A thorough evaluation is critical, because the surgery is not appropriate for all patients and it will not correct all visual problems. It is equally important for patients to learn about LASIX so that they can establish realistic expectations before they make the choice.

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