Consistent comparison of angle Kappa adjustment between Oculyzer and Topolyzer Vario topography guided LASIK for myopia by EX500 excimer laser.

AIM

To evaluate and compare the uniformity of angle Kappa adjustment between Oculyzer and Topolyzer Vario topography guided ablation of laser keratomileusis (LASIK) by EX500 excimer laser for myopia.

METHODS

Totally 145 cases (290 consecutive eyes )with myopia received LASIK with a target of emmetropia. The ablation for 86 cases (172 eyes) was guided manually based on Oculyzer topography (study group), while the ablation for 59 cases (118 eyes) was guided automatically by Topolyzer Vario topography (control group). Measurement of adjustment values included data respectively in horizontal and vertical direction of cornea.

RESULTS

Horizontally, synclastic adjustment between manually actual values (dx) and Oculyzer topography guided data (dx) accounts 35.5% in study group, with mean dx/dx of 0.78±0.48; while in control group, synclastic adjustment between automatically actual values (dx) and Oculyzer topography data (dx) accounts 54.2%, with mean dx/dx of 0.79±0.66. Vertically, synclastic adjustment between dy and dy accounts 55.2% in study group, with mean dy/dy of 0.61±0.42; while in control group, synclastic adjustment between dy and dy accounts 66.1%, with mean dy/dy of 0.66±0.65. There was no statistically significant difference in ratio of actual values/Oculyzer topography guided data in horizontal and vertical direction between two groups (=0.951, 0.621).

CONCLUSION

There is high consistency in angle Kappa adjustment guided manually by Oculyzer and guided automatically by Topolyzer Vario topography during corneal refractive surgery by WaveLight EX500 excimer laser.