title: Tonic vergence, age and clinical presbyopia.
abstract: The relative contribution of tonic vergence to the maximum near vergence response as a function of age and the development of presbyopia has received little attention. Tonic vergence position was measured subjectively in a group of 50 subjects between 20 and 68 years of age. While there was no progressive trend with age, tonic vergence did exhibit a small but consistent convergent increase after 40 years of age. Thus, tonic vergence showed a slight change, possibly of a motor adaptive nature, concurrent with increasing age and the development of clinical presbyopia.
authors.affiliation: State University of New York/State College of Optometry, Department of Vision Sciences, NY 10010.
authors.forename: K J
authors.initials: KJ
authors.lastname: Ciuffreda
authors.forename: E
authors.initials: E
authors.lastname: Ong
authors.forename: M
authors.initials: M
authors.lastname: Rosenfield
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D003290:Convergence, Ocular / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011305:Presbyopia / Q000503:physiopathology*