Flap vs. Flapless Surgical Technique

Your decision between a flap procedure and a flapless procedure will have a significant impact on your postoperative comfort level, how quickly your vision clears, your postoperative activity limitations, and the unique safety profile of your procedure.

With laser vision correction, the actual laser treatment is performed on the cornea – the clear front surface of the eye. The cornea is about 0.5 mm thick and it is composed of five separate layers. When a flap is created, the first few layers are lifted away to expose the middle layer. The laser treatment then reshapes the middle layer and the flap is repositioned to cover the treated area.  Conversely, with a flapless procedure, the laser treatment is placed directly on the surface layer of the cornea.

It is important to understand that the decision between a flap and flapless procedure only determines the layer of the cornea that is treated. It does not say anything about whether standard or customized wavefront technology is used for the actual treatment.

Flap Procedures - LASIK is the most well-known flap procedure, but there are others, such as IntraLASIK. The subtle differences between these procedures are discussed elsewhere. However, all flap procedures have several attractive features that have made them enormously popular.

The biggest advantage of a flap procedure is the speed and comfort of your recovery. Because the surface layer of the cornea is largely undisturbed (it is lifted away intact with the flap and then put back), there is very little discomfort – usually just a scratchy feeling for a few hours. The vision recovers quickly and almost all patients enjoy clear vision the next morning.

If you choose a flap procedure, you'll need to be careful not to rub your eyes for the first month after the procedure so the flap can heal. After a month, you can enjoy your normal day-to-day activities without worrying about the flap, but you will always need to avoid extreme trauma to your eyes, such as martial arts or boxing, because of the remote possibility of flap trauma, even years out from your procedure.

Flapless procedures have a large number of often confusing names. However, there is no practical difference between the subtle variations in technique that these names describe, so we refer to all flapless surgery as PRK.

In comparison with a flap procedure, PRK treated eyes heal slowly. There is a period of 3 to 5 days after PRK when the eyes are often quite scratchy, watery and irritated and medications for discomfort are sometimes required. This period is usually “down time” for the patient and a return to work is generally not possible.

Once the initial 3 to 5 day healing period is complete, the eyes are again comfortable. However, while the vision is typically “good enough to get by”, it often takes several weeks to gain full clarity. Therefore, PRK patients must be willing to wait for their vision to recover.

With the slow healing of PRK, you may be tempted to ask why anyone would consider it. The answer lies in its most obvious advantage - the fact that no flap is made - as there are a variety of reasons why you or your surgeon might prefer a flapless procedure.

For example, patients with thin corneas don't always qualify for flap surgery, so a flapless procedure may be the only alternative. Others may engage in activities or occupations that carry a high risk of flap trauma, such as boxing, police or military work. In these situations, PRK is the preferred option. And some patients simply realize that it is impossible to have a flap-related complication if no flap is made, so they choose a flapless procedure for this slight safety advantage.

Flap Procedure Flapless Procedure