Abstract
Purpose :
Corneal dystrophies are a group of genetic diseases that are classified by the affected corneal layer. Like humans, dogs can exhibit spontaneous corneal stromal dystrophies and can thus serve as clinical disease models. Herein, we describe the imaging characteristics of a novel, central stromal corneal dystrophy affecting young adult dogs.
Methods :
Five dogs (3 males castrated and 2 females spayed) with a mean ± SD age of 4.0 ± 2.28 years and five breeds (Labrador Retriever, Golden Retriever, Whippet, Australian Shepherd and one mixed breed dog) were included in the study. All dogs were evaluated with Fourier-domain optical coherence tomography (FD-OCT) and in vivo confocal microscopy (IVCM). The Shapiro-Wilk test was used to test data normality (P < 0.05) for central total corneal thickness (CCT), epithelial thickness (ET), stromal thickness (ST), Descemet’s membrane-endothelial complex (DMET) and density of keratocytes in the anterior and posterior stroma and endothelium. The aforementioned parameters from the affected dogs were statistically compared with Mann-Whitney test to 8 healthy, female Beagles 0.52 ± 0.12 years.
Results :
All dogs had well demarcated, gray-whiteish ovoid axial corneal anterior stromal opacities in both eyes which appeared as a band of hyperreflectivity in the anterior stroma. Median ± interquartile range values generated with FD-OCT were 637 ± 2, 76.5 ± 26.0, 545.5 ± 207.0 and 23.5 ± 5.0 µm for CCT, ET, ST and DMET, respectively. For the Beagles, the CCT and ET were lower, 560.5 ± 271.0 56.0 ± 37.0 µm respectively (P < 0.0016). With IVCM, hyperreflective stroma, punctate deposits within the stroma and activated keratocytes were observed. Anterior and posterior stromal keratocyte and endothelial cell density from dog with corneal dystrophy were 222 ± 213, 204 ± 173.0 and 2215.0 ± 1080 cells/mm2, respectively which was significantly lower versus that of the Beagles (975.5 ± 281.8, 794 ±151, 2858 ± 352 cells/mm2; P ≤ 0.004). No signs of inflammation were present including corneal vascularization or inflammatory cells.
Conclusions :
The ophthalmic examination and multimodal corneal imaging findings combined with the young age of the patients are consistent with a novel central corneal stromal dystrophy. Further investigations are warranted over time in these patients as well as examination of related dogs to determine if it is progressive and the putative underlying genetic cause.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.