Quantitative forced ductions in an animal model - Characterization of passive forces

Steven E. Brooks, Jack C Yu, Dean Preston, Maribeth H Johnson

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Purpose: Our purpose was to characterize the passive tissue forces involved in ocular rotation in a controlled animal model and to evaluate the influence of manual versus mechanized ductions, repeated measurements, speed of rotation, and the influence of the nondepolarizing muscle relaxant mivacurium. Methods: Forced ductions were performed under general anesthesia on 20 eyes of 10 pigs, with or without mivacurium, with use of a highly sensitive force gauge attached to the eye by a traction suture. The eye was moved either manually or at constant speed with a motorized platform. Eyes were rotated a total of 8 mm from their resting position under anesthesia. The force-displacement relationship was analyzed and compared between groups. Results: A linear (elastic) relationship between force and displacement was noted, with a slope of 0.4 g per degree with use of the mechanized technique. Neither speed of rotation, use of mivacurium, nor repeated ductions significantly influenced the shape or slope of the relationship. Hysteresis averaged 2 to 4 g. Measurements performed with use of the motorized platform showed significantly improved reliability over those made manually. Conclusions: The passive length-tension data correlate well with data reported by others in humans. Within a wide range of eye movement, this force is elastic in nature. For relatively low angular velocities, such as might be produced in smooth pursuit, the passive forces do not change appreciably with changes in velocity. The nondepolarizing muscle relaxant mivacurium has no effect on accurate performance of passive forced ductions under general anesthesia. Studies collecting quantitative data on passive orbital forces should be performed, when feasible, with an automated duction and recording apparatus.

Original languageEnglish (US)
Pages (from-to)239-245
Number of pages7
JournalJournal of AAPOS
Volume2
Issue number4
DOIs
StatePublished - Jan 1 1998

Fingerprint

Animal Models
General Anesthesia
Smooth Pursuit
Muscles
Traction
Eye Movements
Sutures
Swine
Anesthesia
mivacurium

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Ophthalmology

Cite this

Quantitative forced ductions in an animal model - Characterization of passive forces. / Brooks, Steven E.; Yu, Jack C; Preston, Dean; Johnson, Maribeth H.

In: Journal of AAPOS, Vol. 2, No. 4, 01.01.1998, p. 239-245.

Research output: Contribution to journalArticle

@article{c611350dceac478b86c2e8cc470ade8b,
title = "Quantitative forced ductions in an animal model - Characterization of passive forces",
abstract = "Purpose: Our purpose was to characterize the passive tissue forces involved in ocular rotation in a controlled animal model and to evaluate the influence of manual versus mechanized ductions, repeated measurements, speed of rotation, and the influence of the nondepolarizing muscle relaxant mivacurium. Methods: Forced ductions were performed under general anesthesia on 20 eyes of 10 pigs, with or without mivacurium, with use of a highly sensitive force gauge attached to the eye by a traction suture. The eye was moved either manually or at constant speed with a motorized platform. Eyes were rotated a total of 8 mm from their resting position under anesthesia. The force-displacement relationship was analyzed and compared between groups. Results: A linear (elastic) relationship between force and displacement was noted, with a slope of 0.4 g per degree with use of the mechanized technique. Neither speed of rotation, use of mivacurium, nor repeated ductions significantly influenced the shape or slope of the relationship. Hysteresis averaged 2 to 4 g. Measurements performed with use of the motorized platform showed significantly improved reliability over those made manually. Conclusions: The passive length-tension data correlate well with data reported by others in humans. Within a wide range of eye movement, this force is elastic in nature. For relatively low angular velocities, such as might be produced in smooth pursuit, the passive forces do not change appreciably with changes in velocity. The nondepolarizing muscle relaxant mivacurium has no effect on accurate performance of passive forced ductions under general anesthesia. Studies collecting quantitative data on passive orbital forces should be performed, when feasible, with an automated duction and recording apparatus.",
author = "Brooks, {Steven E.} and Yu, {Jack C} and Dean Preston and Johnson, {Maribeth H}",
year = "1998",
month = "1",
day = "1",
doi = "10.1016/S1091-8531(98)90059-3",
language = "English (US)",
volume = "2",
pages = "239--245",
journal = "Journal of AAPOS",
issn = "1091-8531",
publisher = "Mosby Inc.",
number = "4",

}

TY - JOUR

T1 - Quantitative forced ductions in an animal model - Characterization of passive forces

AU - Brooks, Steven E.

AU - Yu, Jack C

AU - Preston, Dean

AU - Johnson, Maribeth H

PY - 1998/1/1

Y1 - 1998/1/1

N2 - Purpose: Our purpose was to characterize the passive tissue forces involved in ocular rotation in a controlled animal model and to evaluate the influence of manual versus mechanized ductions, repeated measurements, speed of rotation, and the influence of the nondepolarizing muscle relaxant mivacurium. Methods: Forced ductions were performed under general anesthesia on 20 eyes of 10 pigs, with or without mivacurium, with use of a highly sensitive force gauge attached to the eye by a traction suture. The eye was moved either manually or at constant speed with a motorized platform. Eyes were rotated a total of 8 mm from their resting position under anesthesia. The force-displacement relationship was analyzed and compared between groups. Results: A linear (elastic) relationship between force and displacement was noted, with a slope of 0.4 g per degree with use of the mechanized technique. Neither speed of rotation, use of mivacurium, nor repeated ductions significantly influenced the shape or slope of the relationship. Hysteresis averaged 2 to 4 g. Measurements performed with use of the motorized platform showed significantly improved reliability over those made manually. Conclusions: The passive length-tension data correlate well with data reported by others in humans. Within a wide range of eye movement, this force is elastic in nature. For relatively low angular velocities, such as might be produced in smooth pursuit, the passive forces do not change appreciably with changes in velocity. The nondepolarizing muscle relaxant mivacurium has no effect on accurate performance of passive forced ductions under general anesthesia. Studies collecting quantitative data on passive orbital forces should be performed, when feasible, with an automated duction and recording apparatus.

AB - Purpose: Our purpose was to characterize the passive tissue forces involved in ocular rotation in a controlled animal model and to evaluate the influence of manual versus mechanized ductions, repeated measurements, speed of rotation, and the influence of the nondepolarizing muscle relaxant mivacurium. Methods: Forced ductions were performed under general anesthesia on 20 eyes of 10 pigs, with or without mivacurium, with use of a highly sensitive force gauge attached to the eye by a traction suture. The eye was moved either manually or at constant speed with a motorized platform. Eyes were rotated a total of 8 mm from their resting position under anesthesia. The force-displacement relationship was analyzed and compared between groups. Results: A linear (elastic) relationship between force and displacement was noted, with a slope of 0.4 g per degree with use of the mechanized technique. Neither speed of rotation, use of mivacurium, nor repeated ductions significantly influenced the shape or slope of the relationship. Hysteresis averaged 2 to 4 g. Measurements performed with use of the motorized platform showed significantly improved reliability over those made manually. Conclusions: The passive length-tension data correlate well with data reported by others in humans. Within a wide range of eye movement, this force is elastic in nature. For relatively low angular velocities, such as might be produced in smooth pursuit, the passive forces do not change appreciably with changes in velocity. The nondepolarizing muscle relaxant mivacurium has no effect on accurate performance of passive forced ductions under general anesthesia. Studies collecting quantitative data on passive orbital forces should be performed, when feasible, with an automated duction and recording apparatus.

UR - http://www.scopus.com/inward/record.url?scp=0032130940&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032130940&partnerID=8YFLogxK

U2 - 10.1016/S1091-8531(98)90059-3

DO - 10.1016/S1091-8531(98)90059-3

M3 - Article

C2 - 10532743

AN - SCOPUS:0032130940

VL - 2

SP - 239

EP - 245

JO - Journal of AAPOS

JF - Journal of AAPOS

SN - 1091-8531

IS - 4

ER -