Morphometrical analysis of the canine choroid in relation to age and sex using spectral domain optical coherence tomography

Abstract

This study determined the choroidal thickness of senior (SN, n = 24) and middle-aged (MA, n = 17) healthy, mixed-breed mesocephalic dogs, both males (M) and females (F), using spectral domain optical coherence tomography (SD-OCT). The dogs were divided into two groups for examination: MA dogs (4–7 years old; 6 M, 11 F) and SN dogs (8–13 years old; 12 M, 12 F). Choroidal thickness of the dogs was investigated using SD-OCT radial and linear scans. The software of the device allowed determination of the exact measurement location on the choroid. Measurements of the choroid were taken manually using the SD-OCT calliper function at distances of 5,000–6,000 μm (dorsal and ventral) and 4,000–7,000 μm (nasal and temporal) from the optic disc. Mean (µm ± SD) (MA, SN) dorsal (188 ± 28, 184 ± 33), ventral (116 ± 23, 111 ± 16), temporal (152 ± 31, 151 ± 26), and nasal (135 ± 27, 132 ± 18) choroidal thicknesses demonstrated significant differences (P < 0.02–0.001) between all areas within each group. The choroid was thickest in the dorsal region and thinnest in the ventral region. There were no significant differences based on age. Mean (µm ± SD) (M, F) dorsal (181 ± 32, 190 ± 30), ventral (117 ± 16, 11 ± 21), temporal (150 ± 26, 153 ± 30), and nasal (128 ± 20, 138 ± 23) choroidal thicknesses demonstrated significant differences (P < 0.05) between dorsal and nasal regions. The choroidal thickness in dogs depends on the area assessed independently of their age and sex.

Morphological and Morphometric Analysis of Canine Choroidal Layers Using Spectral Domain Optical Coherence Tomography

“…In our previous study, we analyzed whole choroidal thickness in dogs in the D, V, T, and N regions. However, the T and N regions were not differentiated into tapetal and nontapetal regions [ 31 ]. Choroidal thickness in the D and V regions was comparable to the values reported in the present study.…”

“…The choroidal thickness in the temporal region was found to be 152 and 151 µm in the MA and SN groups, respectively. Moreover, the choroidal thickness in the N region was found to be 135 and 132 µm in the MA and SN groups, respectively [ 31 ]. In the present study, the choroidal thickness was 175 and 182 µm in the TempT region in the MA and SN groups, respectively.…”

“…The study was also approved by the Scientific Research Committee of the Department and Clinic of Animal Surgery at the University of Life Sciences in Lublin (#3/2018) concerning non-experimental clinical patients. Some of the patients in whom measurements of individual choroidal layers were performed were patients included in the authors’ most recent studies on the total thickness of the choroid [ 31 ].…”

“…In our previous study, we analyzed whole choroidal thickness in dogs in the dorsal (D), ventral (V), temporal (T), and nasal (N) regions [ 31 ]. Choroidal thickness in dogs depends on the area being assessed and not on the age of the dogs.…”

“…No statistically significant difference was observed in the whole choroidal thickness in each choroidal region between dogs of different age groups. In both senior (SN) and middle-aged (MA) mixed-breed dogs, the D region was the thickest, followed by the T region, and the V region was the thinnest [ 31 ]; however, in the previous study, division into choroidal layers was not considered.…”