Abstract
Purpose :
A marmoset, one of the nonhumanoid primates, has been considered an excellent model in ophthalmology owing to similar visual optics matching to humans, including high visual acuity and macular formation. It has a relatively high reproductive rate and is also potentially suitable for transgenic transformation compared to other nonhumanoid primates such as rhesus and crab-eating monkeys. However, because a commercialized OCT used in clinics for humans was used to image the marmoset’s retina, it was difficult to obtain wide field-of-view retinal images. In this study, we developed a high-resolution wide-field spectral-domain optical coherence tomography (SD-OCT) to get marmoset retinal images.
Methods :
Figure 1 shows our SD-OCT. The SD-OCT used an SLD with a -3dB bandwidth of 100 nm at 850 nm to obtain the marmoset's retinal images. The scan head was mounted on a goniometer to make scanning positions easier. We developed a head holder to reduce motion artifacts caused by human hand movements and marmoset movements. The speed of a line-scan camera in a spectrometer was set to 80 kHz. The SD-OCT was based on USB 3.0 and parallel processing with a GPU to be displayed in real-time on a laptop computer and be portable.
Results :
Figure 2 shows the marmoset’s retinal OCT images. An axial resolution was 2.3 μm in tissue (n = 1.37). In previous studies that utilized commercialized OCTs for clinics, only the optic nerve or macular area could be imaged due to the small field of view. We could obtain wide-field OCT images with an optical scan angle of 60 degrees. As a result, it became possible to get cross-sectional images of both the optic nerve and macular of a marmoset in a single image. Furthermore, the high axial resolution allowed for clear visualization of the ELM layer, the thinnest layer in the retina. The foveal center and parafoveal area thicknesses were 197.8 μm and 260.4 μm, respectively.
Conclusions :
We have demonstrated a high-resolution and wide-field SD-OCT that utilizes a laptop computer for imaging a marmoset’s retina. With an optical angle of 60 degrees, our OCT allowed for the acquisition of a single cross-sectional image of both the optic nerve and macular in a marmoset’s retina. In addition, the high axial resolution made it possible to visualize the ELM layer. We plan to obtain OCT angiographic images of a marmoset’s retinal blood vessel networks.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.