Abstract
Purpose:
In both humans and dogs, the primary risk factor identified for optic nerve damage in glaucoma is an elevated intraocular pressure (IOP). This IOP increase can be cause by irido-corneal angle (ICA) abnormalities. In addition, oxidative stress (OS) processes are incriminated in the retinal ganglion cells dysfunction and optic nerve degeneration occurring during glaucoma. Recently, a suspected inherited form of glaucoma was identified in Eurasier dog (ED), a selected breed for which pedigrees are easily available. We therefore assessed the ICA morphological status, in addition to plasmatic levels of OS biomarkers in a cohort of ED in order to definite predictive markers of glaucoma using this dog model.
Methods:
The production of an Eurasier family tree including 830 subjects from 26 generations allowed the assessment of a selection of 28 subjects by veterinarians from the Reseau Europeen d’Ophtalmologie Veterinaire et de Vision Animale (REOVVA). This cohort was composed in 4 groups: 7 young males and 9 young females (1 to 3-year old) versus 6 adult males and 6 adult females (4 to 8-year old). For all dogs, ophthalmological examinations were performed according to recommendations of the Association French Eye Panellists (AFEP/MHOC) eye scheme including ophthalmoscopy, tonometry, gonioscopy, biometry and ultrasound biomicroscopy (UBM). Measurements of plasmatic glutathion peroxidase activity (GPA) were also performed on all dogs.
Results:
Gonioscopic examinations revealed goniodysplasia in 79% of adult dogs (75% and 83% in males and females, respectively), and in 21% in young dogs. Moreover, elevated IOP levels were significantly correlated with a reduced global axial length, and surprisingly with an increased distance of the Schwalbe’s lens anterior capsule, in adult female (p=0.03). Finally, the GPA was significantly reduced (-61%) as compared to a randomized control group, constituted by a panel of different breed of dogs.
Conclusions:
ICA abnormalities, associated with a reduction of antioxidant production, found in ED, suggest that this breed may constitute a canine model suitable for occurrence of glaucoma. This cohort will be use as sentinelle in order to perform a longitudinal monitoring of the disease development in these currently healthy dogs especially those presenting GD and their future puppies.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
420 anterior chamber •
634 oxidation/oxidative or free radical damage