title: Binocular and Accommodative Characteristics in a Normal Population.
abstract: To study binocular and accommodative characteristics and their associations with age and gender in an Iranian young adult population.
  
  
  
  In this cross-sectional study, multistage cluster sampling was done from the students of Mashhad University of Medical Sciences. All participants had visual acuity, refraction, and cover tests followed by measurements of the near point of convergence (NPC), amplitude of accommodation (AA), monocular and binocular accommodative facility (MAF and BAF) using ±2.00 diopter (D) flipper lenses, and negative and positive relative accommodation (NRA and PRA). Near and distance fusional vergence reserves were measured using prism bar, and near associated phoria was assessed using the Mallett unit.
  
  
  
  The mean age of the participants was 22.5±4.4 years (range: 18-35 years). The binocular and accommodative characteristics and their means in the studied sample included: mean distance dissociated phoria: 1.15 exophoria±2.04 prism diopters (PD), near dissociated phoria: 5.02 exophoria±4.74 PD, near associated phoria: 0.55 base-in±1.02, gradient accommodative convergence/accommodation (AC/A) ratio: 4.66±1.59, NPC: 5.27±3.60 cm, MAF: 11.33±5.58 cpm, BAF: 8.84±4.47 cpm, NRA: 2.08±0.33 D, PRA:-2.92±0.76 D, and AA: 11.14±2.6 D. In the multiple regression model including age and gender, near exophoria was significantly higher in men and levels of near base-out-break and near base-out-recovery were higher in females. Distance exophoria, distance base-in-break, distance base-in-recovery, and NPC increased with age and near base-out-break, PRA, BAF, MAF, and AA significantly decreased with age.
  
  
  
  Studied indices in this study significantly differ from available guidelines and these differences must be considered when making diagnostic or therapeutic decisions. Certain indices can be affected by age and gender.
authors.affiliation: a Department of Optometry , Mashhad University of Medical Sciences , Mashhad , Iran.
authors.forename: AbbasAli
authors.initials: A
authors.lastname: Yekta
authors.affiliation: b Department of Medical Surgical Nursing , Shahid Beheshti University of Medical Sciences , Tehran , Iran.|c Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital , Tehran , Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
authors.affiliation: d Noor Ophthalmology Research Center, Noor Eye Hospital , Tehran , Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.affiliation: e Refractive Errors Research Center, Mashhad University of Medical Sciences , Mashhad , Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Ostadimoghaddam
authors.affiliation: a Department of Optometry , Mashhad University of Medical Sciences , Mashhad , Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Ghasemi-Moghaddam
authors.affiliation: e Refractive Errors Research Center, Mashhad University of Medical Sciences , Mashhad , Iran.
authors.forename: Javad
authors.initials: J
authors.lastname: Heravian
authors.affiliation: f Department of Optometry , Iran University of Medical Sciences , Tehran , Iran.
authors.forename: Asgar
authors.initials: A
authors.lastname: Doostdar
authors.affiliation: c Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital , Tehran , Iran.
authors.forename: Payam
authors.initials: P
authors.lastname: Nabovati
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D012737:Sex Factors; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
keywords: binocular/accommodative characteristics; cross-sectional study; distribution; fusional reserve