Tasks of the retina

The retina of the eye, also known as the retina, is responsible for transmitting stimuli to the brain. It is therefore responsible for ensuring that what we see is perceived as an image. The light must first pass through the cornea, the lens and the vitreous body of the eye before it reaches the retina inside the eye.

The retina consists of millions of sensory cells. The reflected light information of the object seen is picked up by the cells of the retina, sorted, bundled and finally sent via the optic nerve as an impulse to the brain. These tasks are performed by the different cell types that are interconnected in the retina.

Furthermore, the retina performs tasks in vitamin A metabolism and represents a kind of border between it and the blood vessels located directly next to it in the choroid. These blood vessels supply the retina. The barrier ensures that no harmful substances from the blood can enter the retina. The retina also contains the area of sharpest vision, the so-called macula or fovea centralis. Only cones are located here.

Physiology of the retina

When a light stimulus hits the eye, it must first pass through several different structures of the eye to the photoreceptors. First, the light impulse hits the cornea in the anterior chamber of the eye, passes through the pupil, posterior chamber, lens and vitreous body. In order to reach the photoreceptors, the light pulse must pass through the two inner layers of the retina.

Once the light stimulus has reached the sensory cells, this light stimulus is converted into electrochemical stimuli and transmitted to the two inner layers of the retina.The cells of the inner layer form the optic nerve, which transmits the stimuli to the brain, where they are processed and perceived. There are three types of cones for color and brightness vision, consisting of red, green and blue cones. The rods responsible for twilight vision are virtually switched off at brightness and cannot perceive colors.

In darkness only rods are active, so color vision is also difficult in twilight and darkness. The photoreceptors and bipolar cells have a certain resting activity (potential). When stimulated, they pass on this information by increasing or decreasing the potential.

The ganglion cells in turn pass on their information via electrical signals (action potentials), i.e. they are frequency-coded. Thus, brightness and color have different frequencies, whose frequency code is decoded in the brain and translated into an image. The photoreceptors and bipolar cells have a certain resting activity (potential).

When stimulated, they pass on this information by increasing or decreasing the potential. The ganglion cells in turn pass on their information via electrical signals (action potentials), i.e. they are frequency-coded. Thus, brightness and color have different frequencies, whose frequency code is decoded in the brain and translated into an image.