Graduate School of Educational Sciences, Ondokuz Mayis University, Samsun, Turkey.
Faculty of Veterinary Medicine, Department of Anatomy, Ondokuz Mayis University, Samsun, Turkey.
Microsc Res Tech. 2024 Oct;87(10):2408-2417. doi: 10.1002/jemt.24624. Epub 2024 Jun 1.
The anatomical structures forming the eyeball differ among dog breeds, both morphologically and morphometrically. This study was aimed at determining the morphometric values of the eyeball layers of different dog breeds and the morphological structures of these layers using scanning electron microscopy. Thirty-two eyeballs of 17 dogs belonging to 9 different breeds that died from traffic accidents, falling from a height, and naturally were used. These dog breeds were grouped according to their brachycephalic and mesocephalic skull structures, and morphometric measurements of the eyeballs of each group were obtained. Scanning electron microscopy was used to examine the morphological structure of the eyeball layers. The studied dogs' eyeballs comprised three layers: outer, middle, and inner. Thickness measurements obtained from three different regions of the eyeball indicated that the equatorial region was the thinnest among all dog breeds. Moreover, the cornea, which is covered by the sclera along its edges, was thicker at the corneal limbus than at the corneal vertex. A positive correlation was observed between lens thickness and the number of ciliary processes, which varied according to the dogs' head structures. Notably, depression was observed in the posterior surface of the lens in brachycephalic dogs. The morphometric values of the eyeball layers in the brachycephalic and mesocephalic dog breeds were also determined. These values will help researchers study this subject, and the determined morphometric and morphological values will contribute to the anatomy literature. RESEARCH HIGHLIGHTS: This comprehensive study investigates the morphometric and morphological variations in the eyeball layers of different dog breeds, utilizing scanning electron microscopy to analyze eyeballs. It reveals significant breed-specific differences, particularly between brachycephalic and mesocephalic dogs, regarding eyeball layer thickness, corneal structure, lens thickness, and the number of ciliary processes.
眼球的解剖结构在不同犬种中存在差异，无论是在形态上还是在形态计量学上。本研究旨在通过扫描电子显微镜确定不同犬种眼球各层的形态计量值以及这些层的形态结构。使用了 32 只来自 17 只狗的眼球，这些狗死于交通事故、从高处坠落和自然死亡。这些犬种根据其短头颅和中头颅颅骨结构进行分组，并获得了每个组眼球的形态计量测量值。使用扫描电子显微镜检查眼球层的形态结构。研究用狗的眼球由三层组成：外层、中层和内层。从眼球的三个不同区域获得的厚度测量值表明，赤道区域是所有犬种中最薄的区域。此外，角膜在其边缘被巩膜覆盖，在角膜缘处比在角膜顶点处更厚。在不同犬种的头部结构中，观察到晶状体厚度与睫状突数量之间存在正相关。值得注意的是，短头颅犬的晶状体后表面观察到凹陷。还确定了短头颅和中头颅犬种眼球各层的形态计量值。这些值将有助于研究人员研究这个课题，并且确定的形态计量和形态学值将有助于解剖学文献。研究亮点：本综合研究利用扫描电子显微镜分析眼球，调查了不同犬种眼球各层的形态计量和形态变化。它揭示了显著的品种特异性差异，特别是在短头颅和中头颅犬之间，涉及眼球层厚度、角膜结构、晶状体厚度和睫状突数量。
