The Green Grass of Your Eyeballs

What am I looking at?

Here we see three RPEs with their cell bodies in brown (1) grown on a biodegradable scaffold in blue (2) and projections (small tendrils) emerging from the top of these cells in green (3).

Biology in the Background

The retina is the part of the eye that detects light and allows us to see. It is located at the back of the eye and contains cells that detect light, process visual information, and send that information to the rest of the brain.  

The retinal pigment epithelium is a single layer of cells at the base of the retina that separates the retina from the layers of blood vessels and connective tissue below known as the choroid. This barrier layer is composed of cells called retinal epithelial cells and serves to protect and support other cells in the retina, such as photoreceptors and retinal ganglion cells.  

RPEs contain a pigment called melanin that absorbs the excess light that is not absorbed by the photoreceptor cells, preventing photoreceptors from becoming oversaturated with light information. In addition, these cells are joined tightly together, forming a barrier between the blood vessels in the choroid layer and other cells in the retina. Part of the responsibility of this barrier is to control the passage of nutrients and other molecules from the bloodstream to the retina. Dysfunction or degeneration of RPE cells contributes to various retinal diseases, including age-related macular degeneration.

RPE cell bodies of these cells are typically about 14 micrometers across, roughly 5 times smaller than the width of a human hair.

Technique

This image was created using scanning electron microscopy.