Cotton Candy for the Eyes

What am I looking at?

In this image we are looking down on the cells of the retinal pigment epithelium. Individual cells (1) are distinguished by the small fissures (2) that run through the image. Researchers at the National Eye Institute used AI to refine this image, increasing the speed at which the image was captured as well as the image contrast.

Biology in the Background

The retina detects light and allows us to see. It is located at the back of the eye and contains specialized cells, such as photoreceptors, which detect light, and retinal ganglion cells, which process visual information and send that information to the brain.  

The retinal pigment epithelium (RPE) is a single layer of cells at the base of the retina that separates and protects the retina’s specialized cells from the layers of blood vessels and connective tissue below known as the choroid. This barrier is composed of retinal epithelial cells.  

Retinal epithelial cells contain a pigment called melanin that absorbs excess light not absorbed by the photoreceptor cells, preventing the light from scattering and bouncing back to the photoreceptors, thus enhancing visual acuity. 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 the RPE contributes to various retinal diseases, including age-related macular degeneration.

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

Technique

These images were created using confocal microscopy.