Ocular higher-order aberrations in individuals screened for refractive surgery.

PURPOSE: To explore the distribution of ocular higher-order aberrations (HOAs, 3rd to 6th orders) in the population, evaluate the symmetry of ocular aberrations between right and left eyes in each subject using a Hartmann-Shack wavefront sensor, and study the differences in aberration as a function of age.
SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.
METHODS: Ocular HOAs were examined across a 6.0 mm pupil in 532 eyes of 306 subjects (mean age 41 years +/- 10 [SD] [range 20 to 71 years]; mean WaveScan spherical equivalent -3.39 +/- 2.84 diopters [D] [range -11.56 to 7.60 D]) using the WaveScan system (Visx, Inc.). Zernike coefficients and root-mean-square (RMS) values of HOAs, spherical aberration (SA, Z(4)(0) and Z(6)(0)), and coma (Z(3)(-1), Z(3)(1), Z(5)(-1), and Z(5)(1)) were analyzed. Correlation analysis was performed to assess the association between ocular HOAs and age and investigate the aberration symmetry between right and left eyes.
RESULTS: For individual terms, the highest mean absolute values were for 4th-order SA (Z(4)(0)), 3rd-order coma, and trefoil terms. The mean RMS values of HOA, SA, and coma were 0.305 +/- 0.095 microm, 0.128 +/- 0.074 microm, and 0.170 +/- 0.089 microm, respectively. Moderate to high correlations were found between the right and left eyes for HOA, SA, and coma (Pearson correlation coefficient = 0.601, 0.776, and 0.511, respectively; all P<.001). Thirteen of the 22 Zernike terms (59%) were significantly correlated across eyes (Bonferroni correction, P'<.05/22). Higher-order aberrations, SA, and coma were weakly correlated with age (r = 0.317, 0.273, and 0.176, respectively; all P<.002).
CONCLUSION: Wavefront aberrations varied widely among subjects and increased slightly with age. A moderate to high degree of mirror symmetry existed between right and left eyes.