90 micron flaps get the thumbs up

Using a femotsecond laser (IntraLase) to create flaps of 90 microns does not increase the postoperative risk of striae formation or induction of optical aberrations, according to Omid Kermani and colleagues from Augenklinik am Neumarkt, Cologne, Germany.

A total of 25 eyes (18 patients) were treated with the femtosecond laser, applying an intended thickness of 90 microns. A further 25 eyes (14 patients) received LASIK flap cuts with a conventional microkeratome (MK 2000; Nidek), applying an intended flap thickness of 130 microns. All eyes were treated for myopia or myopic astigmatism with the Nidek EC CXIII refractive excimer laser.

No vision threatening complications occurred in any of the treatments and in all eyes, the flap could be opened and repositioned after laser ablation. Dr Kermani conceded that the 90 micron flaps were slightly more difficult to lift compared with normal femtosecond flaps of 120 microns.

The mean femtosecond flap thickness was 95 microns with a standard deviation of ±10 microns and the mean microkeratome flap thickness was 115 microns with a standard deviation of ±25 microns.

Ninety percent of all eyes (from both groups) were within ±0.5 D of target refraction and one day after LASIK, all eyes had a visual acuity of 0.8 or more. Furthermore, no eyes lost more than one line of best corrected visual acuity.

Dr Kermani concluded that flaps with a thickness below 100 microns were not associated with an increased postoperative risk.