The Accuracy of the Orbscan-derived Total Refractive Power after Laser in Situ Keratomileusis

ABSTRACT

PURPOSE: This study was performed to evaluate the correlation between the change of the manifest refraction and change of the Orbscan-derived total refractive and axial power after laser in situ keratomileusis (LASIK). METHODS: A total of 34 consecutive eyes of 19 patients who were followed up for at least6 months after LASIK were included in study. The manifest refraction and Orbscan topography analysis of the 2, 3, 4, and 5 mm diameter zones of total refractive power and axial power maps were measured preoperatively and at least 6 month postoperatively. RESULTS: There were statistically significant correlations between all Orbscan-derived corneal power changes and changes of manifest refraction. Especially the total refractive power map in the central 4.0 mm zone gave the best statistically significant correlation with manifest refractive change (r2=0.790, p<0.01). CONCLUSIONS: These results indicate that the change of the manifest refraction in LASIK is best correlated with the change of the total refractive power map in the central 4.0 mm zone.