The Ratio of Accommodative-Convergence to Accommodation in Patients with Nonrefractive Accommodative Esotropia

Rebecca Kim; Se Youp Lee

doi:10.3341/jkos.2014.55.2.267

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Kim and Lee: The Ratio of Accommodative-Convergence to Accommodation in Patients with Nonrefractive Accommodative Esotropia

Original Article

J Korean Ophthalmol Soc 2014;55(2):267-270.

Published online: 7 September 2014

DOI: https://doi.org/10.3341/jkos.2014.55.2.267

The Ratio of Accommodative-Convergence to Accommodation in Patients with Nonrefractive Accommodative Esotropia

Rebecca Kim, MD, Se Youp Lee, MD, PhD

Department of Ophthalmology, Keimyung University School of Medicine, Daegu, Korea

Address reprint requests to Se Youp Lee, MD, PhD Department of Ophthalmology, Keimyung University Dongsan Medical Center, #56 Dalseong-ro, Jung-gu, Daegu 700-712, Korea, Tel: 82-53-250-8400, Fax: 82-53-250-7705, E-mail: lsy3379@dsmc.or.kr

Received 29 March 201325 June 2013 Accepted 20 December 2013

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To measure the ratio of accommodative-convergence to accommodation (AC/A ratio) in patients with nonrefractive accommodative esotropia in comparison to refractive accommodative esotropia and normal groups.

Methods

A total of 43 subjects were divided into 3 groups: the nonrefractive accommodative esotropia group (group 1), the refractive accommodative esotropia group (group 2) and the normal group (group 3). Age, sex, age of onset, and refractive errors were recorded. The deviation angle was measured near and at distance by using a prism cover test. The AC/A ratio was calculated using a gradient method.

Results

Refractive errors were 2.3 ± 1.7 D (OD) and 2.4 ± 2.1 D (OS) in group 1, 4.8 ± 0.9 D (OD) and 4.6 ± 1.1 D (OS) in group 2, and -0.3 ± 1.5 D (OD) and -0.5 ± 1.5 D (OS) in group 3. Group 2 had higher mean refractive errors than groups 1 and 3, while the difference in refractive error between group 1 and group 3 was not statistically significant. The AC/A ratio was 5.5 in group 1, 2.1 in group 2 and 2.2 in group 3; there was no significant difference between groups 2 and 3, while group 1 had a significantly higher AC/A ratio than both of these groups.

Conclusions

AC/A ratio in patients with nonrefractive accommodative esotropia is higher than that of refractive accommodative esotropia or normal children. It could be used for bifocal lens as non-surgical treatment.

Keywords: Nonrefractive accommodative esotropia, Ratio of accommodative-convergence to accommodation, Refractive accommodative esotropia

References

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Table 1.

Subject and subgroup demographics

	Group 1^*	Group 2^†	Group 3^‡	p-value
Number of subjects	10	17	16
Mean age (years)	6.7 ± 4.0	7.0 ± 2.7	7.7 ± 2.2	0.667
Sex distribution (male:female)	6:4	10:7	5:11	0.210
Age at onset of esodeviation (months)	31.1 ± 14.5	22.8 ± 9.1	-	0.127
BCVA (log MAR)
Bilaterality	-0.09 ± 0.10	-0.09 ± 0.13	-0.02 ± 0.13	0.189
PD (mm)	54.1 ± 5.2	54.5 ± 3.9	55.0 ± 3.7	0.840

Values are presented as mean ± SD.

BCVA = best corrected visual acuity; PD = interpupillary distance.

^* Nonrefractive accommodative esotropia

^† Refractive accommodative esotropia

^‡ Normal.

Table 2.

Comparison of refraction error and AC/A ratio in each group

		Group 1^*	Group 2^†	Group 3^‡
Refractive error
	OD	2.3 ± 1.7	4.8 ± 0.9	-0.3 ± 1.5
	OS	2.4 ± 2.1	4.6 ± 1.1	-0.5 ± 1.5
AC/A ratio		5.5 ± 1.3	2.1 ± 0.7	2.2 ± 1.1

Values are presented as mean ± SD.

RE = refraction error.

^* Nonrefractive accommodative esotropia

^† Refractive accommodative esotropia

^‡ Normal.

Table 3.

Comparison of esodeviation angle in group 1 and group 2

	Group 1^*	Group 2^†	p-value
Initial mean esodeviation angle
Near	24.4 ± 13.1	23.7 ± 9.9	0.980
Distance	14.1 ± 14.5	20.1 ± 8.1	0.223
Mean esodeviation angle with correction
Near	16.5 ± 4.9	2.4 ± 3.4	0.009
Distance	1.5 ± 3.2	-0.1 ± 0.9	0.223
Mean esodeviation angle with +3.00D at near	-0.1 ± 6.4	0.0 ± 5.0	0.824

Values are presented as mean ± SD.

^* Nonrefractive accommodative esotropia

^† Refractive accommodative esotropia

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