Evaluation of the Normal Measurements of Orbital Structures in Healthy Adult Individuals by Using a Magnetic Resonance Imaging Method.

BACKGROUND

This study aims to determine the normal values of orbital structures according to sex in healthy adults.

METHODS

Diameters of extraocular muscles, the width of the optic nerve sheath diameter, the length of the inter-zygomatic line, ocular bulb length, and globe position were measured in the T1-weighed MR (magnetic resonance) images in 204 orbits of 102 individuals.

RESULTS

The mean values of the diameters of the extraocular muscles in males and females were as follows: medial rectus, 3.96 ± 0.52 and 3.58 ± 0.53 mm; lateral rectus, 3.47 ± 0.61 and 3.15 ± 0.48 mm; inferior rectus, 4.47 ± 0.53 and 4.07 ± 0.48 mm; superior rectus, 4.44 ± 0.64 and 4.01 ± 0.56 mm; and superior oblique, 3.68 ± 0.49 and 3.45 ± 0.44 mm. The length of the interzygomatic line in males and females were 102.68 ± 3.89 and 96.95 ± 3.4 mm, the ocular bulb length was 23.33 ± 1.32 and 22.83 ± 1.1 mm, the globe position was 7.66 ± 1.33 and 7.3 ± 1.39 mm, and the width of the optic nerve sheath diameter was 4.65 ± 0.62 and 4.28 ± 0.51 mm, respectively. All measurements were significantly greater for males than for females ( < 0.05).

CONCLUSIONS

We believe that a practical and quantitative method will be provided by this study for the diagnosis and determination of the normative values of orbital structures.