Abstract
Purpose::
To study Bubbles Disappearing Time (BDT) after LASIK flap creation using a Da Vinci® femtolaser device in porcine eyes.
Methods::
A Da Vinci® femtolaser device (Ziemer Ophthalmic Systems AG, Port, Switzerland) was used to create a LASIK flap on 30 freshly enucleated porcine eyes. Complete disappearance of bubbles (CDB) was defined as no bubbles on macroscopic observation within the cornea. In group 1 (n=15), the flap was lifted just after the cut. The time between the end of the cut and CDB was measured. As this time could be influenced by flap lift, the time between the start of flap lift and CDB was also measured. In group 2 (n=15), the flap was left unlifted and the time between the end of the cut and CDB was measured. The kinetics of bubbles disappearance was macroscopically observed.
Results::
The procedure was performed using a vacuum time of 45 seconds. No complications such as suction loss, epithelial defect, or button hole were observed. In group 1, mean time between the end of the cut and CDB was 70 ± 0.1 seconds. Mean time between the start of flap lift and CDB was 44.7 ± 10.7 seconds. This time corresponds also to the time needed to lift the flap, as bubbles disintegrated as soon as the flap was completely lifted. In group 2, mean time between the end of the cut and CDB was 140 ± 22 minutes. However, most of the bubbles had disappeared after about 20 minutes, and only very few bubbles at flap edge took more time to disappear
Conclusions::
Analysis of BDT and kinetics of bubbles disappearance using a Da Vinci® femtolaser device confirms the technical breakthrough of this laser device. Shock waves, cavitation bubbles and gas bubbles are smaller owing to reduced energy threshold required for photo disruption. Accordingly, BDT is decreased and precision of the cut is theoretically increased.When the flap is lifted, BDT is very short and corresponds to time needed to lift the flap. It implies that excimer laser treatment may be performed immediately after flap lift. A relatively short BDT when the flap is left in place allows the surgeon to recut a deeper flap after only 3 hours in case of an incomplete flap, compared to months with a mechanical microkeratome.Further studies on human eyes are needed to confirm the results of this pilot study, however.
Keywords: refractive surgery • refractive surgery: other technologies • clinical laboratory testing