Abstract
Purpose :
Report the results of optical zone enlargement and recentration using topography-guided ablation after previous myopic LASIK.
Methods :
Retrospective analysis of 73 eyes that underwent a topography-guided retreatment for optical zone enlargement or recentration after primary myopic LASIK with the MEL80. Atlas corneal topography, corneal wavefront and manifest refraction were used to generate the ablation profile using the CRS-Master and MEL80 excimer laser. Refractive and visual outcomes were analysed. Optical zone centration and diameter were assessed by electronically overlaying a set of paracentral rings and central grid onto tangential curvature difference maps, with the edge of the optical zone identified as the mid-peripheral power inflection point. The change in corneal spherical aberration was also calculated. Follow-up was 3 to 12 months.
Results :
SEQ was -0.54±0.99 D (-3.75 to +1.00 D) after the primary LASIK and -0.21±0.63 D (-1.88 to +2.25 D) after the topography-guided retreatment, with 71% within ±0.50 D and 92% within ±1.00 D of the intended target SEQ. UDVA after the retreatment (vs CDVA before retreatment) was 20/20 or better in 82% (91%) and 20/25 or better in 93% (92%) of eyes. No eyes lost 2 lines CDVA, and contrast sensitivity was normal and unchanged. Optical zone decentration from the corneal vertex was reduced by 63% from 0.58±0.26 mm (0.05 to 1.28 mm) to 0.21±0.14 mm (0.00 to 0.54 mm). Optical zone diameter was increased by 11% from 5.65±0.52 mm (4.8 to 7.0 mm) to 6.33±0.52 mm (5.0 to 7.6 mm). Corneal spherical aberration was reduced by 46%, coma was reduced by 49%, and higher order RMS was reduced by 39%.
Conclusions :
Topography-guided custom ablation is an effective treatment for decentrations and optical zone enlargement. Refractive accuracy was similar to standard LASIK retreatments.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.