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ETIOLOGY AND INCIDENCE OF LOSS OF SUCTION
Loss of suction can occur during flap creation, either with a femtosecond laser or with a microkeratome.1 Loss of suction can be due to the following:
- Inadequate initial suction
- Patient movement, eye rotation, and/or head tilt
- Flat corneas with dioptric readings of less than 42 diopters (D)
- Smaller palpebral fissure
- Deep set eyes
- Incarcerated conjunctiva
With femtosecond laser, reported loss of suction incidence varies between 0.3% (IntraLase [Abbott Medical Optics]) and 4.4% (VisuMax [Carl Zeiss Meditec Inc]). With microkeratome, loss of suction incidence varies between 0.3% (Amadeus [Abbott Medical Optics]) and 1.2% (Chiron Corneal Shaper [Chiron Vision]).2,3
FEMTOSECOND LASIK COMPLICATIONS AND IMMEDIATE SOLUTIONS
Complication #1: Loss of Suction (During Raster Cut)
Video section: 1 minute 20 seconds
Platform: IntraLase FS60 kilohertz (kHz) (Abbott Medical Optics)
Flap diameter: 9.3 mm
Flap target depth: 100 microns (µm)
The initial surgery on the right eye resulted in an incomplete flap construction due to suction loss occurring at two-thirds the distance across the planned cut (video 2; time: 1 minute 20 seconds; Figures 2-1 and 2-2).
Some practical measures are as follows:
- Lift up your foot from the laser pedal immediately. This is important to avoid cutting the rest of the flap at a different depth.
- Press “Cancel” on the IntraLase platform or the equivalent on other platforms.
- Do not change the applanation cone to ensure that the repeat cut is at the same depth.
- You may consider changing the suction ring after 2 to 3 unsuccessful attempts.
- Femtosecond laser cut may be repeated.
- The vertical limbal pocket typically created to absorb the cavitation bubbles should be deactivated if already created during the first pass.
- Once a new successful flap is created, start the mechanical flap dissection from the section of the flap that has had one raster pass (ie, the most distal portion from the hinge). This will avoid the possibility of dissecting an area where 2 dissection planes could be present.
Figure 2-1. Initial surgery resulted in an incomplete flap construction due to suction loss occurring at two-thirds the distance across the planned cut.
Figure 2-2. Suction ring was reapplied, and the raster pass resulted in complete flap creation. Ablation was subsequently performed on both eyes. Intraoperative corneal pachymetry revealed a flap thickness of 87 μm. On the first day after surgery, the patient had an uncorrected distance visual acuity of 20/25 in each eye, with LASIK flaps clear and well-centered on slit lamp examination. At the 2-month follow-up visit, uncorrected distance visual acuity was 20/20 in each eye.
Figure 2-3. Initial surgery resulted in an incomplete flap construction due to suction loss occurring after the raster cut and before the side cut. Complication #2: Loss of Suction When this complication occurs, the flap bed is fully created, but the suction is lost prior to the creation of the side cut. This prevents the flap from being lifted. Video section: 4 minutes 32 seconds Platform: IntraLase FS60 kHz Flap diameter: 9.3 mm Flap target depth: 100 µm The initial surgery on the right eye resulted in an incomplete flap construction due to suction loss occurring after the raster cut and before the side cut (video 2; time: 4 minutes 32 seconds; Figures 2-3 and 2-4). Some practical measures are as follows: Figure 2-4. Second laser pass was done with disabling the raster cut and decreasing the side cut diameter to 8.7 mm. Ablation was subsequently performed on both eyes. Intraoperative corneal pachymetry revealed a flap thickness of 101 μm. On the first day after surgery, the patient had an uncorrected distance visual acuity of 20/20 in each eye, with LASIK flaps clear and well-centered on slit lamp examination. At the 2-month follow-up visit, uncorrected distance visual acuity was 20/20 in each eye.
(After Raster Cut, Before or During Side Cut)
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