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Wavefront aberrations of human eye are expected to change when the eye accommodates to targets from infinite distance to clear visual threshold distance (25 centimeters distance from target to eye). It is significant to measure and analyze the wavefront aberrations in the accommodated human eye, which helps to evaluate visual performance and has clinical value.
The previous research on the effect of accommodation on the wavefront aberration all adopted subjective measurement technique. In this paper, we firstly adopt Hartmann-Shack wavefront sensor technique, which possesses advantages in comparison with the psychophysical subjective technique such as larger sampling points. Data from 20 eyes are reported in this study. Ages of all subjects range from 19 to 38 and defocus of them range from -6D to +3D. Every pupil size is greater than 5mm for whole eye measurements. No one in this experiment has a record of ocular disease.
Root-mean-square (RMS) and peak-to-valley (PV) values of wavefront aberration have been evaluated. In a comparison between the clear visual threshold condition and the infinite distance condition, the subject DQ has the larger change in RMS wavefront error, from 0.85 μm at infinite distance to 0.43 μm at clear visual threshold distance. The RMS difference is about 0.42 μm which is 50% in proportion to the RMS value at infinite distance. While the subject JL has the smaller change of 23% in RMS wavefront error, just from 0.66 μm to 0.51 μm between two different accommodative conditions. Defocus and astigmatism have been excluded in this paper. It is found that accommodation influences wavefront aberrations of whole eye and the situation varies substantially from individual to individual. We have to consider not only the wavefront aberration at the infinite distance but also that at the clear visual threshold distance during clinical ocular therapy.
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