Abstract
Abstract: :
Purpose: To investigate the relationship between refractive error and optical higher order aberrations (HOA), as measured with Dynamic Skiascopy, in healthy human eyes. Dynamic Skiascopy is a newly available technology in wavefront imaging and uses a time–dependent method, rather than a position–dependent method (Harmann–Shack imaging), in calculating optical aberrations. Methods: Study population consists of 100 normal eyes with and without refractive error. Manifest refraction served as the measurement of refractive error in all subjects. Measurements of monochromatic aberrations over the central 4 mm optical zone were taken using Dynamic Skiascopy (Marco 3–D Wave system). Parameters of HOA recorded include root mean square (RMS) of HOA (3rd–6th order), and coma and trefoil, both representing third order aberrations. Aspherical coefficient (Q value) was also recorded for all eyes. Results: Preliminary data comprising 28 subjects (55 eyes), includes refractive error ranging from +2.25 D to –9.25 D (mean –2.30 D + 2.65 D), all with astigmatism < 1.00 D. The range of measured RMS of HOA is 0.051 to 0.595 (mean 0.158 + 0.100). Pearson correlation coefficient values showed no association of spherical refractive error vs. RMS of HOA (3rd–6th order) (r=0.283), horizontal coma (r=0.268), vertical coma (r=0.208), horizontal trefoil (r= –0.254), and vertical trefoil (r= –0.173). No correlation was also seen between RMS of HOA and Q value (r= –0.0004). Conclusions: Our data thus far shows no association between higher order aberrations, as measured by Dynamic Skiascopy, and the degree of refractive spherical error (with low or no astigmatism), in otherwise normal eyes. Dynamic Skiascopy, utilizing a different method in evaluating HOA, shows similar results as previous findings reported using Hartmann–Shack aberrometry (Cheng et al, Optom and Vis Sci; 80:1, Jan 2003, 43–49). Supported in part by NEI #530EYO1867, Research to Prevent Blindness (to Asbell and Department) and Marco, Inc.
Keywords: refraction • cornea: clinical science • optical properties