Wavefront-optimised versus topography-guided ablation: a contralateral eye study for LASIK in myopia

Session Details

Session Title: Presented Poster Session: Keratorefractive Surgery Outcomes - Myopia

Session Date/Time: Sunday 06/09/2015 | 09:30-11:00

Paper Time: 09:40

Venue: Poster Village: Pod 2

First Author: : A.Pasari INDIA

Co Author(s): :    A. Jain   C. Malhotra   P. Chakma        

Abstract Details

Purpose:

To study and compare the outcomes of wavefront-optimized and topography-guided ablation in contralateral eyes of patients undergoing laser in situ keratomileusis (LASIK) for myopia.

Setting:

Cornea and Refractive Services,Advanced Eye Centre,PGIMER,Chandigarh,India

Methods:

This prospective comparative study comprised 35 patients who had wavefront-optimised ablation in one eye and topography- guided ablation in the fellow eye. The IntraLase iFS(Abbott Medical Optics) was used to create a superior-hinged flap and the MEL80 Excimer Laser(Carl Zeiss MeditecAG) for ablation. The WASCA analyzer(Carl Zeiss Meditec AG) was used to measure ocular wavefront aberrations and the Functional Acuity Contrast Test(FACT) chart, to measure contrast sensitivity before and 1week,1month , 3 month and 6 months after LASIK. The refractive and visual outcomes, ablation characteristics and the changes in aberrations and contrast sensitivity were compared between the 2 ablation profiles.

Results:

Pre-operative mean spherical equivalent refraction was -4.22±1.22D and -4.38±1.30D in wavefront-optimised and topograpthy-guided groups, respectively. 94.29%of eyes in the wavefront-optimised group and 100% in the topography-guided group had UCVA of 20/20 or better; the UCVA of 20/16 was better for the topography-guided group. The mean ablation depth was significantly lower(p<0.001) in the topography-guided group for similar indended correction in both groups. Mean higher order aberrations (RMS) increased from 0.74±0.25μm and 0.75±0.29μm to 1.17±0.45μm and 1.07±0.38μm in the wavefront-optimized and topography-guided groups, respectively. Mesopic contrast sensitivity in topography-guided group was statistically better than that in wavefront-optimised group at high spatial frequencies.

Conclusions:

The visual outcomes of both wavefront-optimised and topography-guided ablation in LASIK for myopia using the using Carl Zeiss Meditec platform and the femtosecond laser are excellent. However, topography-guided ablation provides better refractive outcomes as compared wavefront-optimised ablation while ablating significantly lesser amount of corneal tissue for similar correction. Topography-guided ablation also induces significantly lesser higher order aberrations as well as provided better contrast sensitivity outcomes. Topography-guided ablation can be considered as an effective alternative to other existing ablation profiles in LASIK for primary treatment of virgin myopic eyes.

Financial Interest:

NONE