Citation

Piano ME, O'Connor AR. Invest. Ophthalmol. Vis. Sci. 2013; 54(13): 8204-8213.

Affiliation

Vision Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, United Kingdom.

Copyright

(Copyright © 2013, Association for Research in Vision and Ophthalmology)

DOI

10.1167/iovs.12-10934

PMID

24222309

Abstract

Purpose: To evaluate the impact of degrading binocular single vision (BSV) on performance of fine visuomotor skill tasks requiring speed/accuracy. METHODS: Binocular functions (Frisby/Preschool Randot (PSR) stereoacuity, horizontal phasic prism fusion amplitudes) were measured in visually-normal participants aged 18-40 years (n = 80). Participants performed 2 timed visuomotor tasks: water-pouring (450mL accurately into 5 measuring cylinders at 90mL) and bead-threading on upright needles (30 large, 22 small beads, creating 2 difficulty levels). Task and binocular function measures were repeated in a randomised order with monocular visual acuity (VA) reduced in 3-line increments using convex spherical lenses. Analysis used Kruskal-Wallis/Mann-Whitney U tests and linear mixed modelling. RESULTS: Median Frisby stereoacuity levels were 20" arc at baseline, 55" arc when VA was degraded by 6 lines, 210" arc by 9 lines, and unmeasurable by 12 lines (9 lines in some individuals). Task performance times deteriorated for the large bead task (7-10% between lenses, total 39% from median baseline time of 51s, p < 0.001), and small bead task (0.5-15% between lenses, total 46.5% from median baseline time of 57s, p <0.001). Binocular function measures causing significant fixed effects were base-out fusional amplitudes in both bead tasks (large: p = 0.010, small: p = 0.011) and PSR stereoacuity in the small bead task (p = 0.047). Water-pouring task performance was not significantly affected by changes in any experimental parameter. CONCLUSIONS: Degrading motor fusion as well as stereoacuity significantly affects performance in certain fine visuomotor tasks. This impact is differentially affected by task difficulty.

Language: en