Abstract
Purpose: :
While considerable attention has been in recent years to aberrations associated with foveal vision, relatively little interest has been shown in the aberrations for peripheral vision. Although, it is likely that soft contact lens (SCL) is effective against the off-axis aberration correction of the eye, few reports are available on off-axis optical characteristic of the eye with SCL. In this study, we investigated the off-axis wavefront aberrations (WAs) of the eye with SCL.
Methods: :
Twenty eyes of 10 normal subjects were studied. Spherical soft contact lenses (SCL, FDA Group1) with a power of plano, -3 diopter (D), or -7 D were used. Ocular WAs were analyzed with Hartmann-Shack wavefront sensor (Wavefront analyzer, Topcon Corp, Tokyo, Japan). Subjects were instructed to fixate the five different points of the inner fixation target (center, 4.5 degrees off-axis upward (OXU), downward (OXD), right-side (OXR), and left-side (OXL)) (Hirohara, ARVO, 2008). The WAs were analyzed using normalized Zernike polynomials up to the sixth order defined over a 6-mm diameter area in the center of the pupil. The difference of root mean square (RMS) value of each Zernike coefficient between off-axis and central fixation was calculated.
Results: :
The differences of RMS value (ΔRMS) of vertical coma (Z3-1) were [0.064 / -0.078 µm (OXU / OXD)] in naked eyes and (0.088 / -0.118µm (0D), 0.017 / 0.013µm (-3D), -0.107 / -0.060µm (-7D): (OXU / OXD)) in eyes with SCLs. The ΔRMS of horizontal coma (Z31) were [0.071 / -0.073 µm (OXL / OXR)] in naked eyes and (0.059 / -0.124 µm (0D), -0.022 / -0.036 µm (-3D), -0.047 / 0.039µm (-7D): (OXL / OXR)) in eyes with SCLs. These differences were statistically significant (p< 0.05, ANOVA).
Conclusions: :
Off-axis WAs in the eye were altered by wearing SCLs with different power.
Keywords: contact lens • myopia • aberrations