Sympathetic inhibition of accommodation after sustained nearwork in subjects with myopia and emmetropia

Balamurali Vasudevan, Kenneth J. Ciuffreda, Bernard Gilmartin

Research output: Contribution to journalArticle

Abstract

PURPOSE. The purposes of the present study were to assess the effect of a sympathetic inhibitory pharmacologic agent, timolol maleate, on the magnitude of nearwork-induced transient myopia (NITM) and its decay in different refractive groups for an extended near task duration and to determine the proportion of the young adult population manifesting effective sympathetic access under naturalistic closed-loop viewing conditions. METHODS. Ten subjects with emmetropia and 10 with myopia were tested. They read binocularly for 1 hour at a distance of 35 to 40 cm. NITM was calculated as the difference in distance refractive state after task as compared with before task immediately after reading. All subjects received timolol maleate to block the sympathetic nervous system and betaxolol as a control agent in independent test sessions separated by at least 3 days. Forty minutes after drug instillation, the NITM measurement procedure was repeated. RESULTS. Initial NITM magnitude was larger in subjects with myopia than in subjects with emmetropia before and after timolol instillation. Furthermore, NITM magnitude in subjects with sympathetic access was increased after timolol instillation. In contrast, with the control agent betaxolol, there was no increase. NITM decay duration to baseline was increased after timolol instillation in the subjects with myopia only. Only 15% of the subjects (n = 3 subjects with myopia) demonstrated effective and significant access to sympathetic facility. CONCLUSIONS. Subjects with myopia demonstrated an increase in decay duration with timolol, thus suggesting impaired sympathetic inhibition of accommodation. This may be a precursor for myopia progression in some persons.
Original languageEnglish
Pages (from-to)114-120
Number of pages7
JournalInvestigative Ophthalmology and Visual Science
Volume50
Issue number1
DOIs
Publication statusPublished - Jan 2009

Fingerprint

Emmetropia
Myopia
Timolol
Betaxolol
Drug Instillation
Inhibition (Psychology)
Sympathetic Nervous System
Reading
Young Adult

Bibliographical note

Creative Commons Attribution Non-Commercial No Derivatives License

Keywords

  • myopia
  • sympathetic nerves
  • accommodation
  • beta blockers

Cite this

@article{ce2e1b2813d94201bc9bbfacc3b81288,
title = "Sympathetic inhibition of accommodation after sustained nearwork in subjects with myopia and emmetropia",
abstract = "PURPOSE. The purposes of the present study were to assess the effect of a sympathetic inhibitory pharmacologic agent, timolol maleate, on the magnitude of nearwork-induced transient myopia (NITM) and its decay in different refractive groups for an extended near task duration and to determine the proportion of the young adult population manifesting effective sympathetic access under naturalistic closed-loop viewing conditions. METHODS. Ten subjects with emmetropia and 10 with myopia were tested. They read binocularly for 1 hour at a distance of 35 to 40 cm. NITM was calculated as the difference in distance refractive state after task as compared with before task immediately after reading. All subjects received timolol maleate to block the sympathetic nervous system and betaxolol as a control agent in independent test sessions separated by at least 3 days. Forty minutes after drug instillation, the NITM measurement procedure was repeated. RESULTS. Initial NITM magnitude was larger in subjects with myopia than in subjects with emmetropia before and after timolol instillation. Furthermore, NITM magnitude in subjects with sympathetic access was increased after timolol instillation. In contrast, with the control agent betaxolol, there was no increase. NITM decay duration to baseline was increased after timolol instillation in the subjects with myopia only. Only 15{\%} of the subjects (n = 3 subjects with myopia) demonstrated effective and significant access to sympathetic facility. CONCLUSIONS. Subjects with myopia demonstrated an increase in decay duration with timolol, thus suggesting impaired sympathetic inhibition of accommodation. This may be a precursor for myopia progression in some persons.",
keywords = "myopia, sympathetic nerves, accommodation, beta blockers",
author = "Balamurali Vasudevan and Ciuffreda, {Kenneth J.} and Bernard Gilmartin",
note = "Creative Commons Attribution Non-Commercial No Derivatives License",
year = "2009",
month = "1",
doi = "10.1167/iovs.08-1762",
language = "English",
volume = "50",
pages = "114--120",
journal = "Investigative Ophthalmology and Visual Science",
issn = "1552-5783",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "1",

}

Sympathetic inhibition of accommodation after sustained nearwork in subjects with myopia and emmetropia. / Vasudevan, Balamurali; Ciuffreda, Kenneth J.; Gilmartin, Bernard.

In: Investigative Ophthalmology and Visual Science, Vol. 50, No. 1, 01.2009, p. 114-120.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Sympathetic inhibition of accommodation after sustained nearwork in subjects with myopia and emmetropia

AU - Vasudevan, Balamurali

AU - Ciuffreda, Kenneth J.

AU - Gilmartin, Bernard

N1 - Creative Commons Attribution Non-Commercial No Derivatives License

PY - 2009/1

Y1 - 2009/1

N2 - PURPOSE. The purposes of the present study were to assess the effect of a sympathetic inhibitory pharmacologic agent, timolol maleate, on the magnitude of nearwork-induced transient myopia (NITM) and its decay in different refractive groups for an extended near task duration and to determine the proportion of the young adult population manifesting effective sympathetic access under naturalistic closed-loop viewing conditions. METHODS. Ten subjects with emmetropia and 10 with myopia were tested. They read binocularly for 1 hour at a distance of 35 to 40 cm. NITM was calculated as the difference in distance refractive state after task as compared with before task immediately after reading. All subjects received timolol maleate to block the sympathetic nervous system and betaxolol as a control agent in independent test sessions separated by at least 3 days. Forty minutes after drug instillation, the NITM measurement procedure was repeated. RESULTS. Initial NITM magnitude was larger in subjects with myopia than in subjects with emmetropia before and after timolol instillation. Furthermore, NITM magnitude in subjects with sympathetic access was increased after timolol instillation. In contrast, with the control agent betaxolol, there was no increase. NITM decay duration to baseline was increased after timolol instillation in the subjects with myopia only. Only 15% of the subjects (n = 3 subjects with myopia) demonstrated effective and significant access to sympathetic facility. CONCLUSIONS. Subjects with myopia demonstrated an increase in decay duration with timolol, thus suggesting impaired sympathetic inhibition of accommodation. This may be a precursor for myopia progression in some persons.

AB - PURPOSE. The purposes of the present study were to assess the effect of a sympathetic inhibitory pharmacologic agent, timolol maleate, on the magnitude of nearwork-induced transient myopia (NITM) and its decay in different refractive groups for an extended near task duration and to determine the proportion of the young adult population manifesting effective sympathetic access under naturalistic closed-loop viewing conditions. METHODS. Ten subjects with emmetropia and 10 with myopia were tested. They read binocularly for 1 hour at a distance of 35 to 40 cm. NITM was calculated as the difference in distance refractive state after task as compared with before task immediately after reading. All subjects received timolol maleate to block the sympathetic nervous system and betaxolol as a control agent in independent test sessions separated by at least 3 days. Forty minutes after drug instillation, the NITM measurement procedure was repeated. RESULTS. Initial NITM magnitude was larger in subjects with myopia than in subjects with emmetropia before and after timolol instillation. Furthermore, NITM magnitude in subjects with sympathetic access was increased after timolol instillation. In contrast, with the control agent betaxolol, there was no increase. NITM decay duration to baseline was increased after timolol instillation in the subjects with myopia only. Only 15% of the subjects (n = 3 subjects with myopia) demonstrated effective and significant access to sympathetic facility. CONCLUSIONS. Subjects with myopia demonstrated an increase in decay duration with timolol, thus suggesting impaired sympathetic inhibition of accommodation. This may be a precursor for myopia progression in some persons.

KW - myopia

KW - sympathetic nerves

KW - accommodation

KW - beta blockers

UR - http://www.scopus.com/inward/record.url?scp=58249093377&partnerID=8YFLogxK

UR - http://www.iovs.org/cgi/content/abstract/iovs.08-1762v1

U2 - 10.1167/iovs.08-1762

DO - 10.1167/iovs.08-1762

M3 - Article

VL - 50

SP - 114

EP - 120

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 1552-5783

IS - 1

ER -