Studies of amplitude, insufficiency, and

Topics: Eye, Accommodation, Amplitude of accommodation Pages: 16 (3418 words) Published: March 13, 2014
OCULAR ACCOMMODATION
Studies of amplitude, insufficiency, and
facility training in young school children

Bertil Sterner

Department of Ophthalmology
Institute of Clinical Neuroscience
Göteborg University
2004

ii

ISBN 91-628-5989-7
© Bertil Sterner
Department of Ophthalmology
Institute of Clinical Neuroscience
Göteborg University
Sweden
Printed by Vasastadens Bokbinderi AB

iii

Till minne av
min far Nils och min bror Ulf

iv

v

ABSTRACT
The purpose of this thesis was to establish the sufficiency of the ocular accommodation and to characterize accommodative problems and related symptoms among otherwise healthy young school children. The purpose was also to evaluate an accommodative facility training technique by studying the effect of the training on relative accommodation. Children from a junior level school were invited to participate in an examination of the accommodative function which was then compared to expected age levels. Children aged 9–13 years, referred by School Health Care for near work-related problems and complaining of headaches, blurred vision, asthenopia, loss of concentration, and avoidance of near activity, were also studied. Only children with reduced negative relative accommodation (NRA) and positive relative accommodation (PRA) and/or very slow accommodative facility were included. The subjects used an accommodative facility training technique until they reported that the symptoms had disappeared.

The results showed lower amplitudes than expected in a large group of children and not equivalent to the expected age values. More than one third of the children reported subjective symptoms at near. The incidence of subjective symptoms emerged at the age of 7.5 years and there was significant discrimination ability between low amplitude and subjective symptoms.

In all of the trained children the symptoms gradually decreased and finally disappeared during the training period. The data showed a significant increase, despite some individual variations, in both mean NRA and mean PRA among all children characterized with accommodative infacility due to an impaired relative accommodation.

Accommodation is not as sufficient in young children as expected. Subjective symptoms emerge at the age of 7.5 years and there is a clear relation between accommodative parameters and these subjective symptoms. Clear standards for diagnosing an accommodative dysfunction need to be further refined. The results also indicate that accommodative facility training is an effective method resulting in loss of symptoms and that it also has a real effect on the relative accommodation in patients with impaired relative accommodation. Because accommodative dysfunctions may result in subjective symptoms, it is of great importance to identify this dysfunction to prevent unnecessary near vision problems.

vi

APPENDED PAPERS

This work is based on following papers:
Paper I.
Sterner B., Gellerstedt M., Sjöström A. The amplitude of accommodation in 6–10-year-old children – not as good as expected! (Accepted for publication, Ophthalmic and Physiological Optics).
Paper II.
Sterner B., Gellerstedt M., Sjöström A. Accommodative insufficiency, subjective symptoms, and reference values for young school children. (Submitted).
Paper III.
Sterner B., Abrahamsson M., Sjöström A. (1999). Accommodative facility training with a long term follow up in a sample of school aged children showing accommodative dysfunction. Documenta Ophthalmologica 99: 93–101.

Paper IV.
Sterner B., Abrahamsson M., Sjöström A. (2001). The effects of accommodative facility training on a group of children with impaired relative accommodation - a comparison between dioptric treatment and sham treatment. Ophthalmic and Physiological Optics. 21: 470-476.

The papers are reproduced with kind permission from Kluwer Academic Publishers and Blackwell Publishing.

vii

ABBREVIATIONS
AC/A
C
CA
CNS
cpm
D
DA
NRA
NRM
PC...

References: these changes, an increase in the thickness of the lens, a decrease in its
equatorial diameter, and a reduction in pupil size take place (Brown, 1972)
change in the relative position of the visual axes as a response (Morgan,
1944a)
convergence, and when it decreases, we call this divergence. In addition,
with fixation at near pupillary constriction, miosis occurs (Jampel, 1959;
Von Noorden, 1985). The synkinetic association between accommodation,
convergence, and miosis during fixation at near may be termed the near
muscle and the medial recti muscle (of the eye) (Duke-Elder. 1971). An
accommodative stimulus acts as a trigger which excites innervational
(2002) are schematically illustrated in Figure 4. Pathways to areas that are
known to be, or based on anatomical studies or electrophysiological studies
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • study Essay
  • Case report on: A comparative study of an emmetropic patient to a patient with Accommodative and Convergence Insufficiency Essay
  • Amplitude Modulation Essay
  • Development Study Essay
  • Essay on Feasibility Study
  • study mode Essay
  • Essay about Program of Study
  • study skills Essay

Become a StudyMode Member

Sign Up - It's Free