Transparency is an imaging technique that can be applied to all types of tissue, of variable size. The aim is to obtain a three-dimensional object identical to the basic sample, but completely transparent to allow light to pass through and observe everything in detail.
For observation, the transparent object is then passed through a light-sheet microscope, which takes images of the sample from every angle and then reconstructs a 3D image on the computer. This technique is extremely important, as it enables us to study objects of considerable size: usually, samples observed under a microscope are of the order of a few micrometers. With transparentization, it's possible to accurately observe samples several centimetres in size, which is ten thousand times larger !
The eye is one of the most difficult organs to see through, since the retina contains a layer full of pigments specially designed to block light completely. Without this layer, light wouldn't be able to concentrate at a single point in our eye, and we'd see nothing ! But the presence of this highly pigmented layer was the major problem in creating a transparentization protocol on the eye, since it was difficult to find a way of dissolving these pigments without damaging the eye.
