Definition
The papilla is an area on the retina of the eye. This is where all the nerve fibers of the retina converge and leave the eyeball as a bundled nerve cord in order to be able to transmit the sensory impressions of the eye to the brain.
Anatomy
The papilla is a circular area in the retina of the eye and has a diameter of approximately 1.7 to 2 millimeters, although this can vary individually. In an ophthalmoscopy, also known as ophthalmoscopy, it is a bright, yellowish and circular area that can be clearly distinguished from the rest of the retina. Approximately one million nerve fibers of the retina unite in the papilla and leave the eyeball as a common optic nerve (optic nerve). This nerve transmits the visual information of the eye to the brain after further interconnections. In addition, numerous blood vessels enter the eyeball through the papilla and ensure, among other things, the blood supply to the retina.
Function
The task of the eye is to convert our visual impressions into information for the brain. To do this, light falls on the sensory cells of our retina, which then transmits an electrical signal to downstream nerve fibers. These nerve fibers unite in the papilla and emerge from the eye as an optic nerve.
This is why the papilla is also called the optic nerve head. The papilla itself, on the other hand, has no sensory cells and therefore cannot process visual impressions. It is therefore also colloquially called a “blind spot“. However, as is well known, we do not have a black circle in our field of vision. The reason for this is that the other eye compensates for this loss and what we see is supplemented in our perception to form an image.
Papilla excavation
Papilla excavation is a hollowing of the optic disc. A papilla excavation occurs, for example, when the intraocular pressure is too high and the nerve fibers that leave the eyeball at the papilla are destroyed due to the long-term excessive pressure. The cause of this increased intraocular pressure is usually a flow disorder of the aqueous humor.
The aqueous humor normally has the function to nourish the lens and cornea. Through its circulation from the posterior to the anterior chamber of the eye, it also cleans the eye of foreign matter and pathogens. If, for example, there is a blockage in the so-called Schlemm’s canal, the pressure of the aqueous humor increases on the vitreous body, which in turn presses on the retina and the papilla.
This can lead to the destruction of nerve fibers in the area of the papilla and the retinal areas from which these fibers originated can no longer transmit information to the brain. This leads to a pathological loss of the visual field (scotoma). The extent of the papilla excavation can be determined by an ophthalmoscopy, also called funduscopy or ophthalmoscopy, at the ophthalmologist.
There is already a certain amount of papilla excavation physiologically, which is correspondingly greater in larger papillae than in people with smaller papillae. The ophthalmologist can determine whether this is a pathological form by measuring the cup and determining the resulting visual field defects. Additionally, the intraocular pressure should be determined, which should be between 10 and 20 mmHg.