ABSTRACT
Background Even though the change in wavefront aberrations with correction modality is well documented in the literature,little is known about the underlying mechanism.Complete understanding of the causes responsible for the wavefront change in the combined lens-eye system is important since it provides basic knowledge for further improving the technique to correct refractive error by correcting lenses.Objective The aim of this study was to investigate the influence of refractive correction lens on optical property of the eye by analyzing Zernike aberrations in myopic eyes with contact lens correction.Methods This study was approved by the Ethic Committee of Wenzhou Medical College.Written informed consent was obtained from each subject before entering this study.Zernike aberrations of 52 myopic eyes of 26 subjects with the spherical equivalent-1.75 to-8.50 D were measured using a Hartmann-Shock wavefront sensor.The human eye aberrations were examined at the uncorrected condition,rigid-gas-permeable contact lens (RGP-CL) corrected condition and soft contact lens (Soft-CL) corrected condition.The differences of wavefront aberrations and Zernike coefficients were compared by repeated measurement of single factor variance analysis,and correlation of the aberration changes between uncorrected condition and RGP-CL corrected condition or Sofi-CL corrected condition,between the right eyes and left eyes in different conditions were analyzed by Pearson linear correlation.Results Mean total root-mean-square (tRMS) was (0.71 ± 0.30)μm,(0.54±0.19)μm and (0.74±0.32)μm in the uncorrected condition,RGP-CL corrected condition and Soft-CL corrected condition,with a significant difference (F =8.758,P＜0.001),and tRMS was significant declined under the RGP-CL corrected condition compared with uncorrected condition (t =2.746,P =0.008),and tRMS in RGP-CL corrected condition was significantly lower than that in Soft-CL corrected condition (t =3.428,P =0.001).The high RMS (hRMS) was (0.34±0.12) μm,(0.28 ±0.12) μm,(0.40±0.14) μm in the uncorrected condition,RGP-CL corrected condition and Soft-CL corrected condition,with a significant difference among them (F =10.681,P＜0.001).An insignificant decrease of hRMS was seen in the RGP-CL corrected condition compared with uncorrected condition (t =1.987,P=0.053),but hRMS value was significant higher in the Soft-CL corrected condition than that in the uncorrected condition (t=2.101,P=0.041) and RGP-CL corrected condition (t=4.266,P＜0.001).Compared with uncorrected condition,the axis astigmatism (C5) and spherical aberration (C12) in the RGP-CL corrected condition and spherical aberration (C12) in the Soft-CL corrected condition were significantly reduced (P＜0.05),and the absolute values of trefoil (C6),vertical coma (C7) and tetrafoil (C10) in the RGP-CL corrected condition were lower than those of the uncorrected condition,but vertical coma (C7) absolute value in the Soft-CL corrected condition was increased (P＜0.05).A significantly positive correlation was seen in the spherical aberration (C12) between the RGP-CL corrected condition and uncorrected condition (r =0.763,P＜0.001),and less significant correlation was in the secondary astigmatism (C11) between the Soft-CL corrected condition and uncorrected condition(r=0.469,P＜0.001).Conclusions Different contact lens corrected conditions exert their effects on ocular wavefront structure due to its unique interaction with the eye.RGP-CL wearing has strong modification on wavefront aberrations probably due to its molding effect on corneal surface,which reduces the bilateral symmetry.High order wavefront aberration can be modified by Soft-CL wearing.