What is a free cap? (Posted: jan 2005)

A free cap (also called free flap) is a complication where the flap incision is cut all the way around so that instead of leaving a hinge of attached tissue, the intended flap is a free-standing piece of tissue.

What causes a free cap, and what surgery(-ies) is it associated with? (posted: jan 2005)

Free caps are a complication of LASIK. They typically happen a) when there is a loss of suction while the flap is being created; b) when LASIK is performed on a patient with very flat corneas; or c) (depending what kind of microkeratome is being used) when the flap maker is not properly locked into position.

What are the potential results to the patient? (posted: jan 2005)

Absent other problems, and if handled well, a free cap is not as dramatic as it sounds and in fact early LASIK and ALK procedures were performed without a flap hinge; pressures and surface tension on the cornea help the flap to adhere even without a hinge or sutures. However, the outcome depends on many factors. For example, it is imperative that the cornea be properly marked before surgery because if not, the surgeon has no guide to re-align the flap properly and the patient will suffer a loss of best-corrected vision. Another variable is whether the flap is otherwise regular or is of uneven thickness, whether the surgeon proceeds with the ablation and how well the cap is handled.

How is it diagnosed? (posted: jan 2005)

Visible during surgery and under the slit-lamp afterwards.

How is it treated? (posted: jan 2005)

The cap is replaced and aligned using markings placed on the cornea before surgery. Depending on the quality of the cap the surgeon may or may not proceed with the ablation.

Where can I get more information about free caps? (posted: jan 2005)

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