Abstract
Purpose :
Assess changes in the retinal phenotype of superoxide dismutase 1 knock-out (SOD1-/-) mice, a mouse model of dry age-related macular degeneration (AMD), using in-vivo, multi-functional optical coherence tomography (OCT) imaging.
Methods :
A multi-functional OCT imaging system for small animal ocular imaging was utilized, providing polarization-sensitivity and OCT angiography in addition to the conventional reflectivity contrast. SOD1-/- (n=8) and control littermates (n=9) were imaged between 175 and 567 days of age. Volumetric OCT scans around the optic nerve head (ONH) were acquired and screened for retinal abnormalities. The total and outer retinal thicknesses were assessed in an annulus around the ONH with an inner and outer diameter of 500 and 900 µm, respectively. Drusen-like deposits were manually segmented and evaluated in the same annulus. The longitudinal data were clustered in four age groups centered at 205, 338, 448, and 513 days of age.
Results :
Drusen-like deposits were identified as hyper-reflective lesions in the outer retina of SOD1-/- mice. Deposits were already present at the initial measurement at 205 (±31) days of age. The number of deposits increased with age and a maximum of 22 drusen-like deposits was found in the eye of one mouse at an age of 518 days. The degree of polarization uniformity (DOPU) parameter was determined to identify lesions of the retinal pigment epithelium (RPE) caused by the deposits. The DOPU images had a regular appearance at the lesion sites and resembled the appearance of pseudo-drusen in human AMD patients. Evaluation of the retinal thickness showed thinning of the total and outer retinal thickness over time. Neovascularization was confirmed in both eyes of one animal.
Conclusions :
Drusen-like deposits, retinal thinning and neovascularization were found as the major phenotypic traits in SOD1-/- mice when compared to the control group. The multi-functional image contrast proved to be valuable to characterize hyper-reflective deposits in the outer retina with more detail. Longitudinal preclinical studies of animal models using well established OCT technology may provide a better insight into the phenotype of small animals and thereby may ease the translation of basic research findings from animals to humans.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.