Glaucoma is the leading cause of irreversible blindness in the world and is a slowly progressing neurodegenerative disease of the visual system. While elevated intraocular pressure (IOP) and age are major risk factors, their effects on glaucoma pathogenesis are still incompletely understood [1]. Uncovering the spatiotemporal profiles of glaucoma in the visual system is important for determining the etiology and pathophysiological events of the disease and for guiding targeted therapeutic strategy. In this study, we evaluated the IOP, visuomotor function, anterograde transport and axonal integrity of the visual system at different ages in a chronic inherited glaucoma model using DBA/2J (D2) mice, with an aim to probe the onset of glaucomatous changes and their progression. Age-matched C57BL/6J (B6) mice were assessed as a control.Animal Preparation: Four separate groups of D2 and B6 female mice underwent IOP and optokinetic assessments at 5 (D2/B6, n=6/5), 7 (n=6/5), 9 (n=6/5) and 12 (n=13/4) months old (mos). Manganese-enhanced MRI (MEMRI) was performed to a subset of mice after IOP and optokinetic assessments (n=2-6 per time point per D2/B6 group) and the remaining mice were sacrificed for histological evaluation of neurofilaments without Mn injection, so as to avoid potential Mn toxicity to the visual system. IOP measurements: IOP was measured using a handheld TonoLab tonometer (Icare, Finland). A total of 18 measurements were taken and averaged for each eye. Optokinetics: Visual acuity was quantified using an OptoMotry virtual reality system (CerebralMechanics, Inc.) to assess the visuomotor behavior [2, 3]. 100% contrast and rotation speed of 0.12 degrees/s were maintained throughout, while spatial frequency ranged from 0.042 to 0.750 cycles/degree. MEMRI: D2 and B6 mice were intravitreally injected with 0.5μL of 100mM MnCl₂ solution into both eyes and 2D T1-weighted MRI was performed before and 8 hours after MnCl₂ injection using a 9.4-Tesla Varian/Agilent scanner at 100x100µm² in-plane resolution and 0.5mm slice thickness covering the visual system. A saline syringe phantom was placed next to the mouse head for signal normalization. Histological evaluation: D2 and B6 mice were transcardially perfused with 4% paraformaldehyde. The brains were then removed and the optic nerves were stained for phosphorylated neurofilaments (pNF) for confocal microscopy assessments. The IOP of D2 mice began to increase significantly at 9mos and increased further at 12mos, whereas no apparent IOP change was observed in B6 mice across age (Figure 1). Visual acuity of D2 mice continued to worsen from 5 to 9 mos with no apparent difference between 9 and 12 mos (Figure 2). B6 mice also appeared to perform better than D2 mice at each age during optokinetic assessments (Figure 2). For MEMRI, similar extents of Mn enhancement was observed along the visual pathway in the prechiasmatic optic nerve, lateral geniculate nucleus and superior colliculus of both D2 and B6 mice at 5 and 7 mos (white arrows in Figure 3a). Mn enhancement remained observable in B6 mice at 9 and 12 mos, but was gradually diminished in D2 mice at 9 mos and was not noticeable at 12 mos (Figure 3a). Significant reduction in Mn-enhancement began to be found in the superior colliculus of D2 mice at 9 mos, which progressed further at 12 mos (Figure 3b). At 12 mos, the optic nerve and lateral geniculate nucleus also showed reduced Mn enhancement (Figure 3b). Histological staining of pNF in the optic nerve showed accumlated signals in D2 mice at 5 and 7 mos (Figure 4). pNF signal in D2 mice gradually weakened from 5 to 9 mos and was apparently not noticeable at 12 mos. pNF stain in B6 mice did not show apparent changes across age from 5 to 12 mos.The spatiotemporal profiles of IOP, visuomotor function, anterograde transport and axonal integrity in the visual system of both D2 and B6 mice were characterized. Anterograde Mn transport along the visual pathway in D2 mice began to be disrupted at the onset of IOP increase at 9 mos and progressed further at 12 mos along with further IOP increase and neurofilament loss. Visual acuity in D2 mice appeared to deteriorate earlier than the observable Mn transport disruption or IOP increase, which suggested additional factors other than physiological transport or IOP in contributing to the visuomotor function loss in the current experimental glaucoma model [4-6]. Comparatively, the visual system in B6 mice appeared relatively intact across age. Overall, our results indicate that elevation of IOP may accelerate the deterioration of structure, physiology and function of the visual system in the D2 model of chronic glaucoma across age.