Abstract
Purpose :
Irregular corneal astigmatism is the main reason for reduced vision in patients with keratoconus or decentered ablation after excimer laser treatment. The quality of treatment in these patients has improved over the last 2 decades with all major laser platforms.
All laser companies recommend a two or three step procedure for these eyes, since the refractive outcome might be unpredictable. Herein we present our results with the Mel 90 and the CRS master (Zeiss, Jena, Germany).
Methods :
10 patients (12 eyes) with irregular corneal astigmatism underwent a single session 60 µm transepithelial PTK (optical zone 8.0 mm) and topography-guided PRK (optical zone 7.0 mm). Mitomycin 0.02% was always applied to the laser area for 30 seconds. The diagnoses were keratoconus, forme fruste keratoconus, pellucidal marginal degeneration and decentration after myopic laser treatment. The average age of the patients was 35.0±6.6 (25 - 48) years.
The subjective refraction of the patients was put into the CRS master to correct ametropia and corneal irregularity in one session.
Results :
The steepest axis could be reduced from 47.0±3.2 D to 43.2±4.5 D. Coma was reduced from -0.91µ to -0.15µ. Spherical aberration did not change significantly. UCDVA increased from 1.05 to 0.9 logMAR and CDVA increased from 0.15 to 0.01 logMAR.
None of the patients lost a line of vision. The corneal pachymetry decreased from 489± 33.6µm to 435±52.2 µm.
Conclusions :
Single session transepithelial topography-guided PRK with the Zeiss Mel90 and the CRS Master is a safe and predictable method to correct irregular corneal astigmatism, reduce corneal coma and increase visual acuity.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.