Abstract
Purpose :
Optical coherence tomography (OCT) has been widely used for the diagnosis and monitoring of retinal disease progression. In addition, OCT technique could also be used to monitor light-induced structural changes in the eye. In this study, we examined the light-dependent OCT responses in retinal degeneration (rd10) mouse retina.
Methods :
Mice were kept in normal housing with 14:10-hour light/dark cycle. OCT images of eye were captured using either Bioptigen Envisu UHR2200 or Heidelberg Spectralis. Light-adapted (LA) procedures were performed under room light illumination (~500 lux). Dark-adapted (DA) procedures were performed under dim red illumination after over-night dark-adaptation.
Results :
Compared with WT mice, rd10 mice displayed a significant thinning of total retina thickness at early age, with specific shortening of the outer retina. Light-dependent OCT responses varied among stages of retinal degeneration in the rd10. At Stage I (P21-26), DA induced outer retina changes is significantly reduced compared to WT (1.5±0.5μm for rd10, n=14; 4.6±0.4μm for WT, n=16). As degeneration progresses, Stage II rd10 (P32-38) began to show retinal edema under LA. The amount of edema was significantly reduced after DA. Consequently, there was a big change in outer retina thickness between LA vs DA (6.7±1.2μm, n=10). There is a good correlation between changes in outer retina thickness and the length of outer retina under LA. As degeneration progresses further, Stage III rd10 (P44-45) exhibited large retinal detachment. At this Stage, there is no significant change in outer retina thickness under LA / DA conditions in rd10 retina.
Conclusions :
OCT image is a very useful tool in monitoring fluid dynamics in subretinal space. Retinal degeneration significantly diminished light-dependent OCT responses, indicating importance of photoreceptor function in regulating subretinal fluid dynamics. Eyes are capable to remove mild edema by intrinsic mechanisms in subretinal space, as in case for stage II rd10 mice. However, large retinal detachment and edema formation at late stage of retinal degeneration overwhelms intrinsic capacity of the eye. Better management of subretinal fluid dynamics in retinal degeneration eyes could prolong vision in those subjects.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.