title: Proximal and cognitively-induced accommodation.
abstract: The aim of this study was to investigate proximally-induced accommodation (PIA) at two levels of cognitive demand. PIA was assessed by comparing the open-loop accommodative responses to stimuli located at viewing distances of 6 m (0.17 D) and 0.33 m (3 D), respectively. The vergence and accommodation loops were opened by subjects monocularly viewing the targets through a 0.5 mm pin-hole. PIA was measured while subjects either were encouraged to relax and listened to popular music, or performed a relatively demanding mental arithmetic task (counting backwards in sevens). The results indicated that for 4 of the 12 subjects examined, increased cognitive demand produced a marked (greater than +/- 1.00 D) change in the magnitude of PIA. This finding suggests the presence of an interaction between the output of proximally- and cognitively-induced accommodation in these subjects. Such an interaction may hinder attempts to examine individual, non-optical components of accommodation.
authors.affiliation: Schnurmacher Institute for Vision Research, Department of Vision Sciences, SUNY/State College of Optometry, New York 10010.
authors.forename: M
authors.initials: M
authors.lastname: Rosenfield
authors.forename: K J
authors.initials: KJ
authors.lastname: Ciuffreda
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D003071:Cognition / Q000502:physiology*; D003290:Convergence, Ocular / Q000502:physiology; D004215:Distance Perception / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009907:Optometry; D012063:Relaxation / Q000502:physiology