Wavefront Analysis and its Correlation with Refraction and Topography in Normal Eyes

Abstract

Abstract: : Purpose: To evaluate the information captured with the LADARWave wavefront measurement device and correlate it with clinical findings of refraction and computerized corneal topography. Methods: Sixty eyes (30 patients) of healthy individuals having preoperative exam for refractive surgery were enrolled. Complete ophthalmologic exam, corneal topography and wavefront measurements were performed. Correlation between the exams were made. Pearson’s correlation coefficient was assessed for the two continuous variables, adjusting for the repeated measurements. Results: In healthy virgin eyes, the mean values for all higher order aberrations components were: coma = 0.35µm (SD = 0.29), spherical aberrations = 0.36µm (SD = 0.31) and other terms of higher order aberrations = 0.31µm (SD = 0.14). The wavefront sphere term was highly correlated to manifest and cycloplegic sphere measurements (p<0.001), and wavefront cylinder axis was highly correlated to the cycloplegic axis (p=0.021). The mean match percentage was 85% and this value was used as the cutoff point to divide the sample in to two subgroups and verify the influence of match percentage. The high match subgroup had a higher correlation coefficient than the low match subgroup when comparing refraction data, with statistically significant correlation in almost all refraction components for the high match subgroup. Topographic cylinder and axis were not strongly correlated to manifest, cycloplegic or wavefront refraction, but there was a statistically significant correlation between manifest axis and topographic axis (p=0.046). Conclusion: The LADARWave wavefront measurement device is a valuable diagnostic tool in measuring refractive errors and ocular aberrations in normal eyes. A strong correlation between both refraction and topography measurements (cycloplegic cylinder axis with wavefront axis) with wavefront measurements suggests that the LADARWave device may be helpful in preoperative surgical planning.

Keywords: refractive surgery • refractive surgery: other technologies • refractive surgery: corneal topography