WAVEFRONT LASIK

Wavefront-guided LASIK using the iDesign (Abbott Medical Optics Inc.) System can produce highly predictable refractive outcomes in eyes with myopia and myopic astigmatism, with no loss of corrected visual acuity and no loss in quality of vision, said Sarah Moussa MD, University Eye Clinic, Paracelsus Medical University, Salzburg, Austria.

“LASIK treatments using the new iDesign System for treatment planning is effective, safe and reliable, providing excellent refractive outcomes and good results in terms of postoperative higherorder aberrations,” she said at the XXXI Congress of the ESCRS.

Dr Moussa presented the results achieved at two months’ follow-up in a consecutive series of 100 eyes of 56 patients who underwent wavefront-guided LASIK using the iDesign System. The patients had a mean age of 35 years. Their preoperative manifest refraction spherical equivalent had a mean value of -3.8 D and ranged from -7.88 D to -038 D. Their preoperative cylinder had a mean value of -0.99 D and ranged from -4.75 D to 0.0 D.

A single surgeon, Josef Ruckhofer MD, performed all the LASIK procedures. In every case, he used the iDesign System for planning the treatment, the iFS™ femtosecond laser (AMO) to create corneal flaps, and the STAR S4IR excimer laser system, with iris registration and active 3-D eye tracking, for performing the ablations. The new iDesign System provides five measurements within a single capture sequence, including autorefraction, wavefront aberrometry, corneal topography, keratometry and pupillometry, Dr Ruckhofer noted in an interview with EuroTimes.

“The iDesign System offers several key advantages, the higher resolution of the Hartmann-Shack sensor provides more accurate information to the laser for treatment, iDesign can capture 600 to over 1200 data points, depending on pupil size, compared to the maximum of 240 data points with the Wavescan system. The addition of a full gradient topography in the same capture sequence allows us to analyse the wavefront map and the topography at the same time. That in turn enables us to detect if the aberrations are coming only from the cornea or more from the lens,” he added.

At a follow-up of two months, uncorrected visual acuity was 1.0 or better in 99 per cent of eyes, 1.25 or better in 73 per cent of eyes and 1.6 or better in 32 per cent of eyes. In addition, no eyes lost lines of corrected visual acuity, 49 per cent gained one line and five eyes gained two lines. Furthermore, all eyes were within 0.5 D of attempted correction and 96 per cent were within 0.25 D. In all, 21 per cent of eyes were slightly under-corrected and three per cent were slightly over-corrected. Furthermore, residual cylinder was less than 0.25 D in 90 eyes and ranged from 0.26 to 0.5 D in the remaining 10 eyes.

“iDesign is easy to use, providing refractive surgeons with a simple and quick transition from the Wavescan System. In the treatment of astigmatism, the use of the higher-resolution system resulted in fewer outliers, less chance of an axial shift, and a tighter correlation coefficient compared with standard aberrometry. Since these are the first eyes we’ve treated with this new technology in our centre, the results will probably improve after time when nomograms are refined,” Dr Ruckhofer said.