Analysis Of Correlation Between Wavefront Aberration And Objective Accommodation In Normal Human Eyes

Objective:The purpose of this study is to evaluate changes in ocular wavefront aberrations and retinal image quality with objective accommodation in normal human eyes.Further optimise wavefront-guided individualized refractive surgery to improve postoperative visual quality of far vision and near vision.Methods:A total of 42 young healthy volunteers(82 eyes)were examined at our outpatient clinic from January 2017 to June 2017.Inclusion criteria were uncorrected distance vision(UDVA)of 20/20.Subjects’ eyes were all healthy emmetropia with a range of refraction from-0.50 to +0.75D,and astigmatism less than 0.50D.The pupil distance between eyes is relatively large(>6.0cm).The normal eye’s emmetropic eye was examined using an iTrace wavefront aberrometer,and the emmetropia was fixed at a distance of 6.0 m and a distance of 40 cm.The wavefront aberrations at 3 mm and 5 mm pupil diameters before and after recording of the subject’s ocular modulation were measured.The effect of high-order aberration(HOA)on the quality of human vision is analyzed based on the modulation transfer function(MTF)derived from the computer system.Results:1.With 5.0 mm pupils,the mean RMS of the wavefront aberration of the whole eye before the accommodation was 0.196±0.075,and the root mean square of the wavefront aberration after the accommodation was 0.258±0.073.There was a statistically significant difference(P<0.05).2.With 3.0 mm pupils,when the accommodation effect is strengthened,the spherical aberration of the whole eye shifts toward the negative value,and the mean RMS of the spherical aberration before and after the accommodation is 0.007±0.011 and-0.002±0.010,respectively,and there was a statistically significant difference(P<0.05).3.With 5.0 mm pupils,the mean RMS of the spherical aberration of the whole eye before and after the accommodation was 0.032±0.021 and-0.096±0.075,respectively,and there was a significant difference between them(P<0.05).4.With 5.0 mm pupils,there was a significant difference in the MTF curve before and after accommodation for the spatial frequency at 5 and 10(both P<0.05).Conclusions:Ocular wavefront aberrations and retinal image quality changed with accommodation in normal human eyes.Total spherical aberration changed more than other HOAs with accommodation.If all physiological spherical aberrations of presbyopia are eliminated,wavefront-guided LASIK surgery may reduce the visual quality of near vision.In addition,when the patient prefers near vision rather than far vision,it may be advantageous to leave some positive spherical aberration during the procedure.