Abstract
Purpose :
Quantifying optic nerve (ON) axons is the gold standard method of disease progression in glaucoma animal models; however, this can only be done after enucleation. Optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) have been used to monitor pathological changes of the optic nerve head (ONH) and retinal nerve fiber layers in patients with glaucoma. In this study, we report the relationship between the number of ON axons and OCT parameters of the ONH at different disease stages in a clinically relevant canine open-angle glaucoma model (OAG).
Methods :
Dogs with moderate- and advanced- stage OAG due to an ADAMTS10 mutation (6 eyes, 6 dogs) and one normal control (2 eyes, 1 dog) were included. Ages of the dogs with OAG ranged from 3 to 7 years (median of 4 years old); the control dog was 6 years old. An equal number of mutant males (n=3) and females (n=3) were included while the control dog was male. High-resolution spectral-domain OCT and SLO (Spectralis®, Heidelberg Engineering) imaging of the ONH and the peripapillary retina were performed. ONs were collected and embedded in epoxy resin. Semi-thin cross-sections were stained with 1% p phenylenediamine and digitally scanned (Aperio digital pathology slide scanner, Leica). The number of axons in the entire ON was counted manually. An image analysis software (Image J, National Institute of Health) was used to measure the OCT parameters and count ON axons.
Results :
A strong positive correlation was found between ON axon numbers and neuroretinal rim (r=0.91, p<0.01) and ONH area[KA1] s (r=0.73, p=0.04). There was a moderate positive correlation between ON axon number and ONH diameter (r=0.52, p=0.19). A strong negative correlation was found between ON axon numbers and optic cup area (r=-0.75, p=0.03) and a moderate negative correlation between ON axon numbers and the age of dogs[KA2] with OAG (r=-0.70, p=0.12).
Conclusions :
OCT and SLO parameters of the ONH area showed a moderate to a strong correlation with ON axon numbers in the canine ADAMTS10-OAG model.
This is a 2021 ARVO Annual Meeting abstract.