Determination and comparison of retinal variations in the Chios and Çine Çapari sheep breeds through funduscopic examination

Objective: This study aimed to determine retinal variations in healthy Chios and Çine Çaparı sheep breeds through fundus imaging and to compare the obtained data. Materials and Methods: The material consisted of 30 Chios and 30 Çine Çaparı sheep breeds, aged 24 months, whose development was completed, and were deemed healthy based on anamnesis information, physical and eye examinations. Fundus images were obtained using a fundus camera, transferred to a computer environment, and recorded. The normal variations of the fundus, tapetal color, tapetal reflection, tapetal homogeneity, optic disc, optic nerve head and retinal endothelium location, color, shape, diameter, and boundaries were examined. The relationship between the color of the fur and the pigmentation of the tapetal region was investigated, and the course and diameter ratios of retinal vessels were determined. Results: In Chios sheep, the color distribution of the tapetal area in the right eye was blue-green 19 (63.3%) and blue 11 (36.7%), while in the left eye, it was blue-green 21 (70%) and blue 9 (30%). In Çine Çaparı sheep, the pigment structure of the tapetal region epithelium in the right eyes was blue-green in 23 (76.7%) and Green in 7 (23.3%), while in the left eyes, it was blue-green in 21 (70%) and green in 9 (30%). In Chios sheep, the pigment structure of the nontapetal region epithelium in the right eyes was brown in 27 (90%) and black in 3 (10%), while in the left eyes, it was brown in 22 (73.3%) and black in 8 (26.7%). In Chios sheep, the pigment structure of the nontapetal region epithelium was black (100%) in all eyes (n=60). The shape of the optic disc in Chios sheep was oval in 29 (96.7%) of the right eyes and 29 (96.7%) of the left eyes, and round in 1 (3.3%) of both eyes. In Çine Çaparı sheep, the shape of the optic disc was oval in 28 (93.3%) of the right eyes, round in 2 (6.7%), oval in 27 (90%) of the left eyes, and round in 3 (10%). The presence of Bergmeister's papilla in Chios sheep was observed in 24 (80%) of the right eyes and 26 (86.7%) of the left eyes, while it was not observed in 6 (20%) of the right eyes and 4 (13.3%) of the left eyes. In Çine Çaparı sheep, Bergmeister's papilla was observed in 20 (66.7%) of the right eyes, not observed in 10 (33.3%), observed in 17 (56.7%) of the left eyes, and not observed in 13 (43.3%). In Chios sheep, the number of arteries in the nontapetal area of the right eyes was 1 in 6 sheep, 2 in 23 sheep, and 3 in 1 sheep, while in the left eyes, it was 1 in 5 sheep, 2 in 25 sheep. The number of veins in the nontapetal area of the right eyes was 1 in 19 sheep and 2 in 11 sheep, while in the left eyes, it was 1 in 21 sheep and 2 in 9 sheep. In Çine Çaparı sheep, the number of arteries in the nontapetal area of the right eyes was 1 in 11 sheep, 2 in 19 sheep, and 3 in 2 sheep, while in the left eyes, it was 1 in 11 sheep and 2 in 19 sheep. The number of veins in the nontapetal area of the right eyes was 1 in 19 sheep and 2 in 11 sheep, while in the left eyes, it was 1 in 17 sheep and 2 in 13 sheep. Conclusion: Fundus examination findings of Chios and Çine Çaparı sheep breeds were found to be similar with minor differences. When compared with other sheep breeds, differences thought to be related to breed and geographical location were observed.