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ETIOLOGY AND INCIDENCE OF FLAP TEARS
Femtosecond LASIK
Flap tears occur with the femtosecond laser mostly during flap dissection rather than during flap creation. Femtosecond-created flaps are more resistant to lifting compared with the microkeratome-created flaps. The risk of tear is even higher with thinner flaps. On occasion, a tear may occur at the hinge, leading to a free flap. Flap tears can also occur during the dissection of flaps with a vertical gas breakthrough (VGB). The incidence of torn flaps is approximately between 0.1% and 0.4% in eyes with femtosecond-assisted flaps; similar percentages are found in eyes treated with microkeratome LASIK.1,2
Microkeratome LASIK
Flap tears can also occur with microkeratome LASIK, and are mainly associated with concomitant complications, such as thin and irregular flaps.
Figure 7-1. Initial surgery resulted in an irregular flap cut pattern.
FEMTOSECOND LASIK COMPLICATIONS AND IMMEDIATE SOLUTIONS
Complication #1: Flap Tear During Flap Dissection
Video section: 0 minutes 15 seconds
Platform: IntraLase FS60 kilohertz (kHz) (Abbott Medical Optics)
Flap diameter: 9.3 mm
Flap target depth: 90 microns (µm)
The initial surgery resulted in a flap tear in the periphery during flap dissection (video 6; time: 0 minutes 15 seconds; Figures 7-1, 7-2, 7-3, and 7-4).
Some practical measures are as follows:
- Assess the position of the flap tear within the flap.
- A small peripheral flap tear may be lifted. Dissect the flap toward the tear followed by the rest of the flap until it is entirely free.
- In cases of severe adherence, surgery should be aborted and a plan for a future surface refractive procedure should be established.
- Place a contact lens.
Figure 7-2. Dissection resulted in a flap tear at 9 o’clock on an unusual thin flap.
Figure 7-3. Further dissection resulted in extension of the tear. The flap was repositioned, and the surgery was aborted.
Figure 7-4. Flap was repositioned, and the surgery was aborted. A surface refractive procedure was performed 1 week later. At 3 months postoperatively, the flap was clear and well-centered with no signs of epithelial ingrowth. The uncorrected visual acuity was 20/20.
Figure 7-5. Initial surgery resulted in a black VGB in the periphery.
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