Divergence insufficiency associated with high myopia

Hiromi Kohmoto, Kenji Inoue, Masato WakakuraInouye Eye Hospital, Chiyoda-ku, Tokyo, JapanPurpose: Divergence insufficiency is generally regarded as a neurological event. While high myopia is not a well-known cause of divergence insufficiency, we frequently encounter divergence insufficiency in high-...

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Autores principales:	Masato Wakakura, Kenji Inoue, Hiromi Kohmoto
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2010
Materias:	Ophthalmology RE1-994
Acceso en línea:	https://doaj.org/article/f908b2891bba4bf9b3f2f85943090a7b
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spelling	oai:doaj.org-article:f908b2891bba4bf9b3f2f85943090a7b2021-12-02T00:48:22ZDivergence insufficiency associated with high myopia1177-54671177-5483https://doaj.org/article/f908b2891bba4bf9b3f2f85943090a7b2010-12-01T00:00:00Zhttp://www.dovepress.com/divergence-insufficiency-associated-with-high-myopia-a5959https://doaj.org/toc/1177-5467https://doaj.org/toc/1177-5483Hiromi Kohmoto, Kenji Inoue, Masato WakakuraInouye Eye Hospital, Chiyoda-ku, Tokyo, JapanPurpose: Divergence insufficiency is generally regarded as a neurological event. While high myopia is not a well-known cause of divergence insufficiency, we frequently encounter divergence insufficiency in high-myopia patients. Thus, the purpose of this study was to report detailed information on such cases and examine mechanisms that might potentially be responsible for this disorder.Methods: We investigated 20 cases of high myopia (&gt;-6 D) with divergence insufficiency, 20 cases of high myopia without double vision, and 10 normal cases as controls. Using magnetic resonance imaging (MRI), a coronal image 6 mm anterior to the eyeball&ndash;optic nerve junction was measured and used to examine the extraocular muscle (EOM) path shift and angle of the eye. Higher angles in each patient were used for statistical comparison.Results: In high-myopia patients with divergence insufficiency, ocular axis measurements ranged from 24.8 to 31.0 (mean &plusmn; SD: 27.6 &plusmn; 1.6) mm. In high-myopia patients without double vision, the ocular axis length was 27.6 &plusmn; 1.3 mm. In normal cases, the ocular axis length was 23.5 &plusmn; 1.0 mm. The EOM angles in these patients ranged from 100 to 140 (112.9 &plusmn; 9.7) degrees, which was significantly higher (P &lt; 0.05) than that seen in the high-myopia patients without double vision (average EOM angle, 99.2 &plusmn; 2.8 degrees) and normal cases (average EOM angle, 97.9 &plusmn; 3.8 degrees). However, orbital lengths in the patients were 41.0 to 48.9 (44.6 &plusmn; 2.3) mm, which also differed from the high-myopia patients without double vision (average orbital length, 49.9 &plusmn; 2.0 mm) significantly (P &lt; 0.05). In normal cases, average orbital length was 45.5 &plusmn; 1.6 mm.Conclusion: In high-myopia patients with divergence insufficiency, nasal shift of the superior rectus and an inferior shift of the lateral rectus were observed, but the orbital lengths were normal. Divergence insufficiency may be caused mechanically by shifts of the EOM due to the presence of a long axis. Therefore, high myopia with a long axis can be considered to be a risk factor for the occurrence of divergence insufficiency.Keywords: divergence insufficiency, high myopia, MRI, extraocular muscle Masato WakakuraKenji InoueHiromi KohmotoDove Medical PressarticleOphthalmologyRE1-994ENClinical Ophthalmology, Vol 2011, Iss default, Pp 11-16 (2010)
institution	DOAJ
collection	DOAJ
language	EN
topic	Ophthalmology RE1-994
spellingShingle	Ophthalmology RE1-994 Masato Wakakura Kenji Inoue Hiromi Kohmoto Divergence insufficiency associated with high myopia
description	Hiromi Kohmoto, Kenji Inoue, Masato WakakuraInouye Eye Hospital, Chiyoda-ku, Tokyo, JapanPurpose: Divergence insufficiency is generally regarded as a neurological event. While high myopia is not a well-known cause of divergence insufficiency, we frequently encounter divergence insufficiency in high-myopia patients. Thus, the purpose of this study was to report detailed information on such cases and examine mechanisms that might potentially be responsible for this disorder.Methods: We investigated 20 cases of high myopia (&gt;-6 D) with divergence insufficiency, 20 cases of high myopia without double vision, and 10 normal cases as controls. Using magnetic resonance imaging (MRI), a coronal image 6 mm anterior to the eyeball&ndash;optic nerve junction was measured and used to examine the extraocular muscle (EOM) path shift and angle of the eye. Higher angles in each patient were used for statistical comparison.Results: In high-myopia patients with divergence insufficiency, ocular axis measurements ranged from 24.8 to 31.0 (mean &plusmn; SD: 27.6 &plusmn; 1.6) mm. In high-myopia patients without double vision, the ocular axis length was 27.6 &plusmn; 1.3 mm. In normal cases, the ocular axis length was 23.5 &plusmn; 1.0 mm. The EOM angles in these patients ranged from 100 to 140 (112.9 &plusmn; 9.7) degrees, which was significantly higher (P &lt; 0.05) than that seen in the high-myopia patients without double vision (average EOM angle, 99.2 &plusmn; 2.8 degrees) and normal cases (average EOM angle, 97.9 &plusmn; 3.8 degrees). However, orbital lengths in the patients were 41.0 to 48.9 (44.6 &plusmn; 2.3) mm, which also differed from the high-myopia patients without double vision (average orbital length, 49.9 &plusmn; 2.0 mm) significantly (P &lt; 0.05). In normal cases, average orbital length was 45.5 &plusmn; 1.6 mm.Conclusion: In high-myopia patients with divergence insufficiency, nasal shift of the superior rectus and an inferior shift of the lateral rectus were observed, but the orbital lengths were normal. Divergence insufficiency may be caused mechanically by shifts of the EOM due to the presence of a long axis. Therefore, high myopia with a long axis can be considered to be a risk factor for the occurrence of divergence insufficiency.Keywords: divergence insufficiency, high myopia, MRI, extraocular muscle
format	article
author	Masato Wakakura Kenji Inoue Hiromi Kohmoto
author_facet	Masato Wakakura Kenji Inoue Hiromi Kohmoto
author_sort	Masato Wakakura
title	Divergence insufficiency associated with high myopia
title_short	Divergence insufficiency associated with high myopia
title_full	Divergence insufficiency associated with high myopia
title_fullStr	Divergence insufficiency associated with high myopia
title_full_unstemmed	Divergence insufficiency associated with high myopia
title_sort	divergence insufficiency associated with high myopia
publisher	Dove Medical Press
publishDate	2010
url	https://doaj.org/article/f908b2891bba4bf9b3f2f85943090a7b
work_keys_str_mv	AT masatowakakura divergenceinsufficiencyassociatedwithhighmyopia AT kenjiinoue divergenceinsufficiencyassociatedwithhighmyopia AT hiromikohmoto divergenceinsufficiencyassociatedwithhighmyopia
_version_	1718403472977559552

Divergence insufficiency associated with high myopia

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