A Mouse Eye in 3D

What am I looking at?

This is a video of the vasculature within and around an optically cleared and intact eye of an adult mouse. As the video progresses, the view moves from the exterior of the eye to the interior and back again. The eye is oriented with the back of the eye, where the retina is, facing up and the front of the eye, where the lens is, facing down.

Biology in the background

This video shows how intricate and complex the network of blood vessels around an eye is. These blood vessels provide oxygen and nutrients to the cells of the eye and its surrounding tissues. Blood is supplied to the retina by the central retinal artery, which enters the eye and divides into four branches (these are the most pronounced/thickest vessels visible in the video), each of which supplies blood to a quadrant of the retina. You can see that the larger blood vessels continuously branch into smaller and smaller vessels that eventually turn into capillaries, which is where the red blood cells transfer oxygen to the cells in the surrounding tissue. Capillaries are so small that they’re visible in this video only as a gray haze.

You can also see that the vasculature is especially dense at the back of the eye (facing up in this video), where the retina is located. The retina contains a variety of specialized cells that process visual information. Retinal cells need considerable energy to convert light into an electrical signal that can be sent to the brain – an energy demand that quadruples in dim light. It’s the job of this dense capillary network to meet the energy demands of the retina’s photoreceptors.

In contrast, there is little to no vasculature at the front of the eye (facing down in this video) because this is where the eye’s lens is. The majority of the lens is made up of proteins called crystallins, which require little or no blood flow to enable the lens to perform its function – focusing light onto the retina.

The eye of an adult mouse is about 3 millimeters across, or roughly eight times smaller than a human thumbnail.

Technique

This image was created using a type of fluorescence microscopy called light sheet microscopy.