This article is more than 5 years old. Information may no longer be current.

Better contrast sensitivity seen with femtosecond than microkeratome LASIK flaps

Add topic to email alerts

Receive an email when new articles are posted on

Please provide your email address to receive an email when new articles are posted on .

Subscribe

Added to email alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

Back to Healio

We were unable to process your request. Please try again later. If you continue to have this issue please contact customerservice@slackinc.com.

Back to Healio

Use of a femtosecond laser for LASIK flap creation led to slightly better visual results in patients with myopia than use of a mechanical microkeratome, a prospective study found. Better results in high-spatial-frequency contrast sensitivity with the femtosecond laser may be related to differences in postop corneal higher-order aberrations between the two methods, the study authors said.

Robert Montés-Micó, PhD, of University of Valencia, Spain, and colleagues compared LASIK outcomes in 200 eyes of 100 patients evenly randomized to undergo flap creation with the IntraLase FS femtosecond laser or the Moria Carriazo-Barraquer microkeratome.

The femtosecond laser was used to create flaps 9 mm in diameter and 120 µm thick. On the microkeratome, a 130 µm plate was used to create flaps 9.5 mm in diameter. All ablations were performed using the Visx S2 excimer laser system from Advanced Medical Optics.

All eyes in both treatment groups achieved uncorrected visual acuity of 20/20 or better. No eye lost one or more lines of best corrected visual acuity.

UCVA improved from 0.55 preoperatively to 1.10 at 6 months postop in the femtosecond laser group and from 0.54 to 1.03 in the microkeratome group. Also, 98% of eyes in the femtosecond laser group and 92% of eyes in the microkeratome group were within 0.5 D of target refraction.

The researchers found that eyes in the femtosecond laser group had a slightly better efficacy index, defined as the ratio of postoperative UCVA to preoperative BCVA. The efficacy index was 1.07 in the femtosecond laser group vs. 1 in the microkeratome group.

"Considering that laser ablation rates vary with tissue hydration, by avoiding the need for irrigation tissue hydration may be more standarized with IntraLase than with mechanical keratomes. This would correlate with the better results found in improved BCVA using IntraLase vs. LASIK," the authors said.

The only statistically significant difference noted between groups was in contrast sensitivity at the high spatial frequency of 18 cycles/degree; the femtosecond laser group had a result about 8% better than the microkeratome group (P < .01).

Higher-order corneal aberrations, spherical aberration and comalike aberration all significantly increased in both groups, although the increases were consistently higher in the microkeratome group, according to the study authors.

The study is published in the January issue of Ophthalmology.