The Posterior Portion of the Eyeball and the Muscle Cone in Cases of High Myopia

Accession number;04A0081336
Title;The Posterior Portion of the Eyeball and the Muscle Cone in Cases of High Myopia
Author; AKIZAWA YASUKO (Tokyo Metrop. Ebara Hosp.) YASUZUMI KENJIRO (Tokyo Metrop. Ebara Hosp.) IDA MASAHIRO (Tokyo-Toritsu Ebara Byoin)
Journal Title;Journal of Japanese Ophthalmological Society
Journal Code:Z0666A
ISSN:0029-0203
VOL.108;NO.1;PAGE.12-17(2004)
Figure&Table&Reference;FIG.6, TBL.2, REF.13
Pub. Country;Japan
Language;Japanese
Abstract;Purpose: To study the displacement of the eye-ball of high myopia in the muscle cone. Methods: Three patients with esotropia with high myopia (myopic esotropia group), seven patients with high myopia without esotropia (high myopia group), and eight controls (control group) were examined. Using magnetic resonance imaging, the outer axial length and the displacement of the posterior portion of the eyeball in the muscle cone were measured. In order to neglect individual differences, the coronal scanning was perpendicular to the orbital axis. The displacement was measured in the plane 2 mm and 4 mm anterior from the globe-optic nerve junction. The distance of the displacement was represented by the distance from the center of the globe to the center of the muscle cone. Results: The displacement in the plane 4 mm anterior (mean.+-.standard deviation) was greater in the order of the myopic esotropia group(1.6.+-.0.64mm), the high myopia group(1.2.+-.0.51mm), and the control group(0.059.+-.0.35mm). The displacement of the eyeball was largest in the myopic esotropia group(p<0.001). The outer axial length and the distance of the displacement in all cases was correlated significantly (r=0.93, p<0.01). Moreover, the eyeballs of the myopic esotropia group and the high myopia group were displaced upwards in the temporal area. Conclusions: The posterior portion of high myopia was displaced upwards in the temporal area in the muscle cone regardless of the presence or absence of esotropia. The eyeball originally elongates upwards in the temporal area, not towards the weakest part of the muscle cone. (author abst.)
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