Imaging depth extension of optical coherence tomography in rabbit eyes using optical clearing agents

Abstract

Optical coherence tomography has become an indispensable diagnostic tool in ophthalmology for imaging the retina and the anterior segment of the eye. However, the imaging depth of optical coherence tomography is limited by light attenuation in tissues due to optical scattering and absorption. In this study of rabbit eye both ex vivo and in vivo, optical coherence tomography imaging depth of the anterior and posterior segments of the eye was extended by using optical clearing agents to reduce multiple scattering. The sclera, the iris, and the ciliary body were clearly visualized by direct application of glycerol at an incision on the conjunctiva, and the posterior boundary of sclera and even the deeper tissues were detected by submerging the posterior segment of eye in glycerol solution ex vivo or by retro-bulbar injection of glycerol in vivo. The ex vivo rabbit eyes recovered to their original state in 60 s after saline-wash treatment, and normal optical coherence tomography images of the posterior segment of the sample eyes proved the self-recovery of in vivo performance. Signal intensities of optical coherence tomography images obtained before and after glycerol treatment were compared to analysis of the effect of optical clearing. To the best of our knowledge, this is the first study for imaging depth extension of optical coherence tomography in both the anterior and posterior segments of eye by using optical clearing agents. Impact statement Imaging depth of optical coherence tomography in ophthalmology is limited by light attenuation in tissues due to inherent optical scattering and absorption. In this study, imaging depth of the anterior and posterior segments of rabbit eyes was extended by using optical clearing agents to reduce multiple scattering. This study may provide a potential method for ophthalmic research, such as accommodation, ocular growth, and biometry of the eye, and for diagnosis of posterior scleritis and intra-orbital tumor, such as orbital cavernous hemangioma, optic nerve glioma, and inflammatory pseudotumor.

Enhancement of multimodal imaging of rabbit eyes using optical clearing agents

“…In recent years, optical clearing techniques have been employed to increase the penetration depth of light in tissues and enhance the imaging contrast of deep-seated structures [7][8][9]. In previous studies, we applied optical clearing agents to the anterior and posterior segments of both ex vivo and in vivo rabbit eyes, and significant improvements in the imaging depth of OCT were observed [10]. In this study, we utilized a glycerol solution as an optical clearing agent for the anterior and posterior segments of rabbit eyes to enhance the imaging capabilities of OCT and PAM.…”

Signal improved ultra-fast light-sheet microscope for large tissue imaging

“…To minimize the scattering of light, most clearing techniques improve light penetration by homogenizing the refractive indices (RI) mismatch that exists within the tissue. As a result, more laboratories are now incorporating rapid 3D imaging and histological studies for model organoids or, organisms like mice 4 , 5 , rats 6 , rabbits 7 , fruit flies 8 , and even humans 9 , 10 into their bio-imaging workflows. Regardless of these advancements, imaging tissue at high resolution has its own challenges.…”

Optical clearing agent enhanced multimodal photoacoustic microscopy and optical coherence tomography imaging of rabbit eyes

“…In our previous study, PAM and OCT were combined to detect laser-induced retinal neovascularization (RNV) and choroidal neovascularization (CNV) in rats to provide sensitive and specific features [9][10][11]. And imaging depth extension of OCT in both the anterior and posterior segments of eye was realized by using glycerol solution as the optical clearing agent [12]. In this study, we added optical clearing agents in multimodal OCT and PAM imaging to study the effect of optical clearing agents on scattering and absorption characters of tissues in eyes, and try to enhance the imaging depth to choroid layer.…”