Evaluation of morphometric properties of extraocular muscles by magnetic resonance

Objective: The extraocular muscles in the orbit provide the mobility of our eyes, which enable us to integrate with the outside world. Knowing the morphometric properties of these muscles is of great clinical importance since various pathologies can affect the orbit and the structures within it. In this study, we aimed to determine the normative values of extraocular muscle thicknesses in the Anatolian population; to investigate possible differences between gender, age, right and left sides and to determine the possible relationships between muscle thicknesses and refractive errors caused by the axial length of the eye. Material-Method: We retrospectively analyzed 339 cases over the age of 20 who underwent orbital magnetic resonance imaging (MRI) for various reasons between 2018 and 2024 in the Department of Radiology, Faculty of Medicine, Selçuk University. Axial lengths and coronal sections of the extraocular muscles of 490 eyes of 245 individuals (120 males and 125 females) who met the criteria were measured and variations were investigated. Results: Of the 11 measurement variables on the extraocular muscles, the left side was statistically significantly larger in 3 and the right side in 1 (p˂0.05). No significant differences were observed between axial lengths (p˃0.05). When male and female genders were compared, axial lengths, interzygomatic distance and 7 out of 11 extraocular muscle variables were significantly larger in male gender (p˂0.05). When the differences between the age groups were investigated; the short diameters of the extraocular muscles in individuals in their twenties were statistically significantly smaller than those in older age groups (p<0.05). Conclusion: This is one of the detailed studies presenting the morphometric characteristics of the extraocular muscles and proving that they may vary depending on gender, side and age. It is thought that the information obtained may contribute to the diagnosis and treatment of orbit-related pathologies.