title: The Influence of Induced Astigmatism on the Depth of Focus.
abstract: To evaluate whether an induced astigmatism influences the subjective depth of focus.
  
  
  
  Fifty-one participants aged 18 to 35 years and with a mean spherical equivalent refractive error of -0.51 ± 2.35 DS participated in the study. The accommodation was blocked with three drops of 1% cyclopentolate. Refractive errors were corrected after subjective refraction with a 4-mm artificial pupil. To evaluate the depth of focus (DoF), defocus curves with a spherical range of ±1.5 DS were assessed. The DoF was calculated as the horizontal distance at a threshold level of +0.1 logMAR from the maximum visual acuity (VA). Defocus curves were estimated binocularly during distance (500 cm) and a near vision (40 cm) for two induced axis (ATR in 0° and WTR in 90°) and for a fixed amount of astigmatic defocus of -0.5 DC.
  
  
  
  The mean natural DoF was 0.885 ± 0.316 D for far vision and 0.940 ± 0.400 D for near vision. With induced astigmatism, the DoF for far vision was significantly increased to 1.095 ± 0.421 D (p = 0.006, ANOVA) for the WTR astigmatism but not for the ATR astigmatism (1.030 ± 0.395 D; p = 0.164, ANOVA). The induced WTR astigmatism enhanced the DoF for near vision significantly to 1.144 ± 0.338 D (p = 0.04, ANOVA), and DoF with induced ATR astigmatism (0.953 ± 0.318 D) was not significantly different (p = 1.00, ANOVA). ATR-astigmatism reduced VA by +0.08 ± 0.08 logMAR (p < 0.01, t-test).
  
  
  
  With an induced WTR astigmatism of -0.5 DC, the DoF can be enhanced in the near viewing distance with a marginal loss in binocular VA. The approach of using induced WTR astigmatism can lead to novel optical treatments for presbyopia.
authors.affiliation: *MSc †PhD ZEISS Vision Science Lab, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany (all authors).
authors.forename: Alexander
authors.initials: A
authors.lastname: Leube
authors.forename: Arne
authors.initials: A
authors.lastname: Ohlendorf
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wahl
mesh_terms: D000065:Accommodation, Ocular / Q000187:drug effects; D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology*; D003519:Cyclopentolate / Q000008:administration & dosage; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009184:Mydriatics / Q000008:administration & dosage; D011446:Prospective Studies; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000503:physiopathology; D014787:Vision Tests; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult
chemical_list: D009184:Mydriatics; D003519:Cyclopentolate