title: Influence of additional astigmatism on distance-corrected near visual acuity and reading performance.
abstract: OBJECTIVE
  To investigate the effect of astigmatism on near vision performance.
  
  
  METHODS
  In a consecutive case series 23 eyes of 23 participants were fogged with 0 D, -0.75 D and -1.5 D of with-the-rule (WTR) and against-the-rule (ATR) astigmatism (cylindrical lenses without spherical compensation). All subjects were cyclopleged and distance corrected. Reading acuity (RAc) and speed (RS) were measured with standardised sentences, near visual acuity (NVA) was assessed using single optotypes (Snellen E), all presented on a thin film transistor display using the Salzburg Reading Desk (SRD). Data were analysed using Wilcoxon-matched-pairs test, regression analysis and Bland-Altman analysis.
  
  
  RESULTS
  An increasing amount of astigmatism resulted in a decreased NVA (p=0.16 for -0.75 D, p=0.005 for -1.5 D) and RAc (p=0.002 for -0.75 D, p=0.014 for -1.5 D). WTR astigmatism caused a reduced NVA, RAc and lower RS compared with ATR astigmatism (p<0.001). NVA was better than RAc with no astigmatism, -0.75 D WTR and -1.5 D WTR (p=0.03 for 0 D, p<0.001 for -0.75 D, p=0.03 for -1.5 D). There was no difference between NVA and RAc for -0.75 D ATR and -1.5 D ATR (p=0.06 for -0.75 D, p=0.5 for -1.5 D).
  
  
  CONCLUSIONS
  WTR astigmatism results in reduced reading parameters and NVA for -0.75 D and -1.5 D astigmatism compared with corresponding ATR astigmatism and no astigmatism added. No beneficial effect of astigmatism was detected.
authors.affiliation: Department of Ophthalmology, Johann Wolfgang Goethe-University, , Frankfurt am Main, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Casagrande
authors.forename: Martin
authors.initials: M
authors.lastname: Baumeister
authors.forename: Jens
authors.initials: J
authors.lastname: Bühren
authors.forename: Oliver K
authors.initials: OK
authors.lastname: Klaproth
authors.forename: Christine
authors.initials: C
authors.lastname: Titke
authors.forename: Thomas
authors.initials: T
authors.lastname: Kohnen
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D011932:Reading; D012044:Regression Analysis; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult
keywords: Optics and Refraction; Psychophysics; Vision