134 Int. J. Morphol., 41(1):134-145, 2023. Comparative Morphological and Computed Tomographical Measurements of the Orbit in Cattle and Pig Eyes Mediciones Morfológicas y Tomográficas Computarizadas Comparativas de la Órbita en Ojos de Bovinos y Porcinos M. Abdo 1, 2 ; R. Taher 2 ; A. Erasha 2 & L. Fericean 3 ABDO, M.; TAHER, R.; ERASHA, A. & FERICEAN, L. Comparative morphological and computed tomographical measurements of the orbit in cattle and pig eyes. Int. J. Morphol., 41(1):134-145, 2023. SUMMARY: Understanding species intraocular parameters using computed tomography (CT) scanning is initial and crucial step in ophthalmology. There is a lack of studies that have specialized in estimating the cattle and pig eyes using CT scans. Therefore, this study aimed to describe the anatomical and computed tomography features of cattle and pig eyes and its internal structures. Animal heads that not suffer from any diseases related to the eye were disarticulated. CT scan was performed. Moreover, 10 % fixed buffered formalin Specimens were used for the anatomical description of the eye and the optic nerve in particular. The values of length, width of the lens and globe, radio density of the optic nerve, lens, the anterior chamber, the vitreous chamber, and orbital dimensions were measured. Statistically, all parameters of cattle optic nerve increased significantly than that of the pig except for radiodensity, and angle of the optic nerve. Furthermore, all intraocular parameters of cattle increased significantly than that of the pig except the radiodensity of aqueous and vitreous humor. There was no significant difference between species in the opening angle of the orbit. This study's findings represent a first step toward developing CT reference values for cattle and pigs intraocular structural assessments. KEY WORDS: Cattle; Pig; Computed Tomography; Optic Nerve; Morphometry. INTRODUCTION Cattle and pig are ungulates, even-toed, a hoofed mammal belonging to the Artiodactyla order (cloven hooves) (Olopade et al., 2011; Underwood et al., 2014), cattle is in the suborder Ruminantia (cud-chewing animals), the genus Bos, family Bovidae and obligate herbivores (Underwood et al., 2014). While the pig is a member of the Suidae family of non-ruminant animals, genus Sus, which includes European wild boars and domestic pigs (Moeller & Crespo, 2009). Cattle may perform a variety of tasks, including providing meat, milk, and working animal. Pigs play a vital role as food providers (Moeller & Crespo, 2009). They may be used in translation studies as substitutional to a monkey or a dog for evaluating pharmaceuticals (Swindle et al., 2012). Pigs being a reliable source of the precorneal tear film (Loewen et al., 2016), they may be used in applied ophthalmological research with bioengineering technologies, especially in dry eye research (Menduni et al., 2018). The orbit serves as a house for the eyeball and its components of vision which included the optic nerve, bulbus oculi, the eyelids, the lacrimal gland, and nictitating gland, ocular and extra-ocular muscles, and the orbital bones which protect the organ of vision of the vertebrate (Olopade et al., 2011). Eye protection when considering lens replacement surgery to treat cataracts, blindness due to the globe or optic nerve disease, or during radiotherapy as a sort of interventional therapy, requires determining the size and measurements of the intraocular structure. Also knowledge of the anatomical features of the visual system can serve to increase the diagnostic, therapeutic, and preventive management of ocu- lar diseases for these animals, whether they are kept for human consumption, rescued, or used in research (Lantyer- Araujo et al., 2019). Ocular MRI and Ultrasound are the modalities of choice in cases of ophthalmological disease (Penninck et al., 2001; Nöller et al., 2006). In contrast, CT is more effective at analyzing the orbital cortical bone than MRI and takes less time to scan (Morgan et al., 1994; Dennis, 1 Department of Animal Histology and Anatomy, School of Veterinary Medicine, Badr University in Cairo (BUC), Department of Anatomy and Embryology, Faculty of Veterinary Medicine, University of Sadat City 32897, Sadat City, Egypt. 2 Department of Anatomy and Embryology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City 32897, Egypt. 3 Department of Biology and Plant protection, Faculty of Agriculture, University of Life Sciences "King Michael I" from Timisoara, Romania. Received: 2022-09-05 Accepted: 2022-11-07