title: Individual Differences in Scotopic Visual Acuity and Contrast Sensitivity: Genetic and Non-Genetic Influences.
abstract: Despite the large amount of variation found in the night (scotopic) vision capabilities of healthy volunteers, little effort has been made to characterize this variation and factors, genetic and non-genetic, that influence it. In the largest population of healthy observers measured for scotopic visual acuity (VA) and contrast sensitivity (CS) to date, we quantified the effect of a range of variables on visual performance. We found that young volunteers with excellent photopic vision exhibit great variation in their scotopic VA and CS, and this variation is reliable from one testing session to the next. We additionally identified that factors such as Circadian preference, iris color, astigmatism, depression, sex and education have no significant impact on scotopic visual function. We confirmed previous work showing that the amount of time spent on the vision test influences performance and that laser eye surgery results in worse scotopic vision. We also showed a significant effect of intelligence and photopic visual performance on scotopic VA and CS, but all of these variables collectively explain <30% of the variation in scotopic vision. The wide variation seen in young healthy volunteers with excellent photopic vision, the high test-retest agreement, and the vast majority of the variation in scotopic vision remaining unexplained by obvious non-genetic factors suggests a strong genetic component. Our preliminary genome-wide association study (GWAS) of 106 participants ruled out any common genetic variants of very large effect and paves the way for future, larger genetic studies of scotopic vision.
authors.affiliation: Center for Applied Genomics and Precision Medicine, Duke University School of Medicine, Durham, North Carolina 27708, United States of America.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Bartholomew
authors.affiliation: Department of Ophthalmology, Duke University, Durham, North Carolina 27710, United States of America.
authors.forename: Eleonora M
authors.initials: EM
authors.lastname: Lad
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois 60612, United States of America.
authors.forename: Dingcai
authors.initials: D
authors.lastname: Cao
authors.affiliation: Section Visual Function, Eye Center, Freiburg University, Freiburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Bach
authors.affiliation: Center for Applied Genomics and Precision Medicine, Duke University School of Medicine, Durham, North Carolina 27708, United States of America.
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Cirulli
mesh_terms: D015350:Contrast Sensitivity / Q000235:genetics*; D003710:Demography; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D055254:Night Vision / Q000235:genetics*; D012044:Regression Analysis; D012684:Sensory Thresholds / Q000502:physiology; D013647:Task Performance and Analysis; D014787:Vision Tests; D014792:Visual Acuity / Q000235:genetics*; D055815:Young Adult