Abstract
Purpose: :
To describe the morphology of a previously undescribed duplication phenomenon of the canine Descemet’s membrane (Dm) in relation to signalment, history and ocular disease status
Methods: :
66 canine eyes out of 14,777 canine cases in the Comparative Ocular Pathology database were retrieved. Clinical information regarding signalment, duration and nature of corneal, ocular and systemic history were abstracted from the submission data. The following morphological criteria were recorded: anatomic location, diameter (µm) of corneal layer (CL, adjacent to the cornea) and anterior chamber layer (ACL, adjacent to the anterior chamber) of Dm, matrix material in between Dm portions, corneal endothelial features, Dm overgrowth on the iris surface, further corneal and intraocular features. All cases were stained with HE and PAS.
Results: :
26 different breeds and 3 mixed breeds were included. The mean age at enucleation was 9.19 ± 2.91 years. When reported, the median duration of clinical signs, before enucleation in 51 cases was 17 months, with a range of 0.1-84. In 22/66 eyes, the duplication was multifocal in 7/66, continuous. In 19/66 the duplication was only in the peripheral cornea, in 9/66 at the limbus, and in 9/66 axial. The mean Dm thickness was the same in CL (14.6 ± 6.35 µm) and ACL (14.65 ± 11.05 µm). In 21/66 eyes matrix material were seen in between the CL and ACL and in 14/66 eyes, there were spindle cell nuclei, and in 5/55 cases a broad zone of tissue was seen. The endothelium was attenuated in 43/66 eyes, partially attenuated in 4/66 eyes, absent in 10/66, and normal in 9/66 cases. In 5/66 eyes, a Dm overgrowth on the iris surface with a mean thickness of 10 ± 8.65 µm was noted. Further corneal features were retrocorneal membrane formation in 19/66 and anterior synechia in 14/66 cases. 24/66 cases were aphakic eyes because of previous cataract surgery, 50/66 eyes had chronic (primary/secondary) glaucoma, and 35/66 showed preiridal fibrovascular membranes and peripheral synechia. 14/66 cases had lens luxation (primary/secondary), 17/66 retinal detachment, 10/66 showed intraocular features of blunt trauma (angel recession, retinal scarring/atrophy) and 3/66 had intraocular neoplasms.
Conclusions: :
Canine duplication of Dm has not been previously described. Chronic glaucoma, either primary or secondary due to traumatizing conditions (blunt, intraocular surgery, lens luxation) were observed in these eyes with duplication of Dm.
Keywords: cornea: endothelium • cornea: basic science • pathobiology