Figure 3: Placing of a soft lens. Figure 5: Cutting of the flap with the femtosecond laser. •Complications Complications are rare; some may result in a decrease in the best corrected visual acuity. The possible deve- lopment of corneal opacity (haze) is one of the limits of PRK treatment (fig. 4). Figure 6: Lifting the corneal flap. 1.2. LASIK (Laser Assisted In Situ Keratomileusis) •Surgical procedure The LASIK procedure involves two steps; the creation of the corneal flap, and the reshaping of the cornea with an excimer laser. First, the surgeon creates a corneal flap, which is a thin slice of the cornea. It is cut and flipped open like the cover of a book. There are two methods of cutting the flap, using microkeratome, which involves a blade, or femtosecond lasers which are bladeless (fig. 5). Once the flap has been cut and opened (fig. 6.), an excimer laser is used to remove tissue to re-shape the cornea, correcting the patient’s refractive error (fig. 7). After correcting the cornea, the flap is replaced (fig. 8). •Recovery time and side effects Immediately after the surgery, the patient may feel an eye irritation from scratching to burning, to a lesser Figure 4: Corneal haze. extent than after a PRK. Functional recovery is quicker, with visual acuity often close to final visual acuity from the day after surgery. •Complications Immediate complications are linked to interoperative manipulation or cutting of the flap, that may be free, decentered or incompletely cut. In the initial aftermath, the flap can present folds, which will require repositio- ning. There is possibility of inflammation of the space under the flap (diffuse lamellar keratitis), which requires a topical treatment by corticosteroids. Displacement of the flap is rare, but they can occur following eye trauma, sometimes years after surgery.9 The movement of the flap encourages epithelial ingrowth. This complication is VOL. due to the passing of corneal epithelial cells under the 94/3 corneal flap. International Review of the Armed Forces Medical Services 42 Revue Internationale des Services de Santé des Forces Armées