Abstract
Purpose: :
To evaluate long-term refractive, aberrometric and anatomical results of surface ablation plus corneal PTK-style smoothing for myopia above -7.00 D.
Methods: :
One-hundred-and-fourteen eyes of 69 patients (mean age: 37.7 ± 8.3 years) underwent PRK with NIDEK EC 5000 excimer laser, multiple optical zone approach - ablation zone 4.89 -7.0 mm, transition zone 7.00 -10.00 mm - cross-cylinder technique for astigmatism, and final 10 Hz PTK-style smoothing with masking fluid (hyaluronic acid 4%) over a 10 mm-diameter zone. Corneal thickness was 560.4 ± 30.1µm. Spherical aberration (SA) was -0.21µ ± 0.86µ, and coma 0.14µ ± 0.10µ.
Results: :
Mean preoperative BSCVA was 0.88 ± 0.16 with -9.53 ± 1.18 D SE. Mean preoperative thickness was 560. 4 ± 30.1 µ. Three years after surgery UCVA was 0.79 ± 0.26, BSCVA was 0.92 ± 0.19 with -0.56 ± 0.90 D SE. Mean haze was maximal at month one (0.58 ± 0.35), then progressively decreased and at year three it was 0.11 ± 0.32. After year one refraction and corneal curvature remained stable, with no sign of corneal ectasia. No hyperopia induction by PTK was noticed. One patients - 2 eyes - required retreatment due to undercorrection. Total wavefront error and spherical aberration did not change significantly, while astigmatism decreased and coma increased (both with p< .001).
Conclusions: :
Treatment of high myopia with surface ablation plus corneal PTK-style smoothing proved to be a safe and reliable technique. Wide optical and transition zone prevented increase of spherical aberration and, together with PTK-style smoothing, created a very regular surface with regular healing and almost no haze.
Keywords: refractive surgery • refractive surgery: PRK • refractive surgery: optical quality