Abstract
Purpose :
Taking advantage of the 1.3-µm axial resolution retinal imaging by visible-light optical coherence tomography (vis-OCT) and newly developed fibergram imaging analysis, we aim to determine, for the first time, the early longitudinal changes of RGC axon bundles in the retinal nerve fiber layer (RNFL) during the progression of ocular hypertension-induced glaucoma in mouse in vivo.
Methods :
We focused on the silicone oil-induced ocular hypertension under-detected (SOHU) glaucoma mouse model for simulating secondary post-operative glaucoma. We used a commercial Halo 375 small animal vis-OCT system in this study. To visualize the RGC fiber bundles, we performed temporal speckle averaging (TSA) acquisition and analysis of live mice at different time points after SO injection and IOP elevation. These time points include naïve contralateral naïve control eyes, early time points 1-day, 3-day, 5-day, and 7-day post injection (dpc), and later time points 14 dpc and 21 dpc. We tracked the alterations in lateral bundle width, axial bundle height, cross-sectional area, and the shape of individual bundles from vis-OCT fibergram (Vis-OCTF).
Results :
Our vis-OCTF revealed the dynamic morphological changes of RGC axons in response to ocular hypertension: RGC axon bundles are swelling with increased fiber width and height at early time points and then gradually back to normal preceding significant shrinking at later time points.
Conclusions :
Our study validates that vis-OCTF combined with TSA is a powerful in vivo imaging and analyzing strategy to detect subtle changes of RGC axons in the clinically relevant SOHU glaucoma model. It captured detailed temporal morphological changes following ocular hypertension. These findings contribute to understanding acute glaucomatous changes and lay the foundation for future investigations into neuroprotective strategies.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.