One thousand consecutive IntraLase laser in situ keratomileusis flaps

Purpose

To measure laser in situ keratomileusis (LASIK) flap dimensions created with the IntraLase FS (IL) laser (Intralase Corporation).

Setting

Private practice, San Diego, California, USA.

Methods

Consecutive LASIK flaps created with the IL were measured with subtraction ultrasound at primary and enhancement surgeries. Data were stored in Outcomes Analysis Software and analyzed using MS Excel (Microsoft Corporation) and SSPS software.

Results

The mean achieved flap thickness exceeded the attempted by 9.4 to 34.3 μm. The standard deviation varied from ±10.2 to ±21.7 μm. Preoperative corneal thickness and power did not affect achieved flap thickness. Seventy-three percent of mate eye flaps were within ±15 μm of each other for the 90 μm attempted. The same flaps measured at enhancement were thicker than the primarily measured flaps (n = 58). Diffuse lamellar keratitis and slipped flaps were eliminated with experience. There were no decentered or irregular flaps, epithelial defects, or flap perforations.

Conclusions

Compared with published results of mechanical microkeratomes, the IL reduced the standard deviation of flap thickness as well as the achieved range. It eliminated physical complications associated with mechanical flap creation, and the impact of preoperative pachymetry and corneal power, thereby permitting more myopia to be corrected without risking deep ablations.