title: Effects of spherical aberration on visual acuity at different contrasts.
abstract: OBJECTIVE
  To evaluate the effect of spherical aberration on visual acuity by correcting and inducing spherical aberration using an adaptive optics vision simulator.
  
  
  METHODS
  Laboratory of Vision Science, Capital Medical University, Beijing, and Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, China.
  
  
  METHODS
  An adaptive optics vision simulator comprising a wavefront sensor and a 37-segmented deformable mirror was used to correct and induce aberrations of the eye. The effective ocular wavefront aberration was manipulated with the deformable mirror, as the resulting visual performance was simultaneously measured. Subjective visual acuity measurements were performed with a 6.0 mm pupil. Visual acuity at different contrasts was measured when spherical aberration was fully corrected and the other natural aberrations in the eye were present and when spherical aberration values were induced with the other aberrations corrected.
  
  
  RESULTS
  The natural root-mean-square (RMS) value of spherical aberration in the 8 subjects examined was between -0.11 microm and 0.14 microm. There was no significant improvement in visual acuity with spherical aberration corrected and the subjects' natural aberrations present. When all aberrations were corrected, a decrease in visual acuity occurred when spherical aberration RMS was induced at 0.2 microm and 0.3 microm.
  
  
  CONCLUSIONS
  When fluctuation of other natural aberrations in the eye were present, there was a slight effect on visual acuity when the spherical aberration RMS was approximately 0.1 microm. Therefore, an RMS value of 0.1 microm could be an acceptable amount of spherical aberration when correcting spherical aberrations.
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiong
authors.forename: Ningli
authors.initials: N
authors.lastname: Wang
authors.forename: Shiming
authors.initials: S
authors.lastname: Li
authors.forename: Yun
authors.initials: Y
authors.lastname: Dai
authors.forename: Lixia
authors.initials: L
authors.lastname: Xue
authors.forename: Haoxin
authors.initials: H
authors.lastname: Zhao
authors.forename: Wenhan
authors.initials: W
authors.lastname: Jiang
authors.forename: Yudong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D055095:Optics and Photonics; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult