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Updated: May 7, 2026
High-resolution Fiber-optic Microendoscopy for in situ Cellular Imaging
Published on: January 11, 2011
Cellular Resolution Panretinal Imaging of Optogenetic Probes Using a Simple Funduscope
Adi Schejter1, Limor Tsur, Nairouz Farah
1Faculty of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel.
Purpose:
To acquire and characterize cellular-resolved in vivo fluorescence images of optogenetic probes expressed in rodent retinal ganglion cells, by adapting a low-cost and simple fundus system based on a topical endoscope.
Methods:
A custom endoscope-based fundus system was constructed (adapted from the design of Paques and colleagues). Bright field and fluorescence images were acquired from head-fixed transgenic mice expressing Channelrhodopsin2-eYFP, and Sprague Dawley rats virally transfected with the optogenetic probe GCaMP3. Images were compared to in vitro images of the same structures and were analyzed.
Results:
The fundus system provides high-quality, high-resolution fluorescence images of the eye fundus that span the whole retina. The images allow resolving individual cells and axon bundles in the Channelrhodopsin2-eYFP mice and cellular-scale structures in the GCaMP3 expressing rats. The resolution in mouse eyes was estimated to be better than 20 microm (full width at half maximum) and is only marginally dependent on movement-related blurring.
Conclusions:
The fluorescence-endoscopy fundus system provides a powerful yet simple and widely accessible tool for obtaining cellular resolved fluorescent images of optogenetic and other fluorescent probes.
Translational Relevance:
The new system could prove to be a basic tool for non-invasive in vivo small animal retinal imaging in a wide array of translational vision applications, including the tracking of fluorescently tagged cells and the expression of gene-therapy and optogenetic vectors.
