Abstract
Purpose: :
To compare the change in the radius of the posterior corneal curvature after myopic Laser In Situ Keratomileusis.
Methods: :
fifteen eyes of 15 consecutive patients undergoing myopic LASIK with ALLEGRETTO Eye-Q laser system (WaveLight Inc) had flaps created with the 60 kHz IntraLase femtosecond laser. Preoperatively and 3 months after surgery, posterior corneal curvature measurements were obtained using Visante OCT and were analysed by a custom computer algorithm written in Matlab 7.4 (The Mathworks, Inc.). Corneal hysteresis (CH) and corneal restistance factor (CRF) were measured using the Reichter ocular response analyser (ORA) preoperatively and 3 months afterwards.
Results: :
Preoperative myopic spherical equivalent refraction was -3.77 D +/-1.24[SD]. Preoperative mean CH and mean CRF (10.6 mm Hg +/- 0.9 and 10.3 +/- 0.9 mm Hg, respectively) were significantly higher than postoperative values (8.8 +/- 0.7 mm Hg and 7.5 +/- 0.8 mm Hg, respectively) (P < .01). The mean thickness of the calculated residual stromal bed (RSB) after treatment was 330.2 microm +/- 36.4 (SD). The mean pre- and postoperative radius of posterior corneal curvature were 6.79 +/- 0.18 mm and 6.68 +/- 0.18 mm, respectively (P<0.05). Postoperative decrease in radius was correlated with the RSB (r = -0.27), but not with CH or CRF.
Conclusions: :
Analysis of the radius of the posterior corneal curvature was possible with the Visante OCT. the change in the radius was correlated with the RSB thickness
Keywords: refractive surgery: LASIK • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical