Imaging single cells in the living retina

A quarter century ago, we were limited to a macroscopic view of the retina inside the living eye. Since then, new imaging technologies, including confocal scanning laser ophthalmoscopy, optical coherence tomography, and adaptive optics fundus imaging, transformed the eye into a microscope in which individual cells can now be resolved noninvasively. These technologies have enabled a wide range of studies of the retina that were previously impossible.

► This article reviews advances in retinal imaging in the last 25 years. ► The scanning laser ophthalmoscope increased the sensitivity of retina cameras, allowing video rate imaging of the living retina. ► Optical coherence tomography dramatically increased the axial resolution of retinal images. ► The adaptive optics scanning laser ophthalmoscope increased the lateral and axial resolution of retinal images. ► Adaptive optics can be combined with OCT or fluorescence microscopy to further improve in vivo imaging.