Anatomical Evaluation of Extraocular Muscles and Relationships Among Macula and Optic Nerve in Enucleated Eye

PURPOSE: To make an anatomical evaluation of extraocular muscles, macular and optic nerve in enucleated eyes of live subjects and to compare the results with a previous autopsy study. METHODS: Twenty-four surgically enucleated eyes were studied. The distance from the limbus to the muscle insertion site, muscle width, and the distance between muscle insertion sites were measured and compared with an Apt study. After an incision through the eyeball, a 26-gauge needle was passed perpendicularly through the macula to the sclera. We measured the distances between the oblique muscles and the macula and optic nerves from an external site of the eyeball. RESULTS: The distance from the limbus to the muscle insertion site showed a significant difference in the superior and inferior rectus muscle. All measurements of muscle widths were significantly narrower than those of autopsy studies. The distances between the muscles were significantly closer between the lateral and superior muscles and between the superior and medial rectus muscles. From the optic nerve to the muscle was 3.99+/-0.62 mm, to the superior oblique muscle was 7.89+/-0.88 mm, to the inferior oblique muscle was 5.95+/-0.83 mm, and the macula to the inferior oblique muscle was 1.35+/-0.42 mm. CONCLUSIONS: Since most of the measurements were different from those of autopsy studies, we should consider the effects of preservation and fixation solution on autopsy eyes, race, and the differences among measurement instruments.

Muscle Width and Distance from Limbus to Muscle Insertion Site in Strabismus Patient

PURPOSE: This study investigated the differences of muscle width and distance from limbus to muscle insertion site according to age and sex, and the correlation with ocular axial length and strabismus degree. METHODS: The study subjects were 100 eyes of 50 horizontal strabismus patients undergoing rectus muscles recession. Ocular axial lengths were measured at preoperation, while muscle width and distance from limbus to muscle insertion site were measured during operation. Preoperative and postoperative comparison items were retrospectively investigated with the medical records. Correlations of muscle width, distance from limbus to muscle insertion site and the comparison items were verified by ANOVA test. RESULTS: Muscle width was 10.05+/-0.86 mm in medial rectus muscle and 9.38+/-1.03 mm in lateral rectus muscle. Distance from limbus to muscle insertion site was 5.21+/-0.85 mm in medial rectus muscle and 6.37+/-1.01 mm in lateral rectus muscle. Muscle width and distance from limbus to muscle insertion site had no correlations with ocular axial length and strabismus degree, but ocular axial length was significantly longer in the older group compared to the younger group and in the male group compared to the female group. CONCLUSIONS: It is presumed that muscle width and distance from limbus to muscle insertion site have no relationship with age, sex and strabismus degree.