Pain Adnexe
Adnexes are the appendages of the eye, i.e. muscles, glands, eyelids and eyelashes. Pain in the eye can also always be caused by the periphery, for example the eye muscles. The human being has 4 straight and 2 oblique eye muscles, which are needed for rolling in, rolling out and moving to the right/left and up/down.
Normally, both eyes are synchronously controlled by the respective cranial nerves and moved absolutely evenly. However, if there are deviations in the axis of movement, for example due to a muscle failure in one eye or a unilateral nerve lesion, the eye movement is asynchronous.Three-dimensional vision is created by the two perspectives that our two eyes pass on to the head. The brain calculates a spatial image from these two perspectives.
To do this, however, both eyes must be precisely matched to one another to the millimeter, otherwise the brain cannot make use of the two images – we see twice. Double images, as they occur after eye muscle paralysis, for example, cause headaches and thus also pain. Eye muscle paralysis can be caused by nerve lesions, but also by craniocerebral trauma or stroke.
By the way, 3D films, as we see them in the cinema, are also shot with two cameras slightly offset next to each other – in other words, exactly as our two eyes do. Another source of eye pain is the numerous glands that surround the eye. According to their discoverers and first describers, they have names such as the meibomian gland, the minor gland, or the zeis gland.
Their task is the production of components for the tear fluid. For example, the Meibom glands produce an additive that they release into the tear fluid. It prevents the tear fluid from evaporating too quickly.
If, however, an inflammation of the Meibom glands occurs, a so-called barley grain (or hordeolum) is formed in acute cases and a hailstone (chalazion) in chronic cases. Both are accompanied by redness, swelling and pain. In the case of pain at the edge of the eyelid or the periphery of the eye, one must therefore always think of an inflammation of one of the glands.
The lacrimal gland is of particular importance in this context: it produces the tear fluid that keeps the eye moist and cleans and rinses it. If the lacrimal gland or the tear ducts that drain the tears are obstructed, the supply of tear fluid to the eye is reduced, resulting in dry eyes. This can be the case, for example, if there is a tumor or if the tear ducts are blocked by a stone.
On the one hand the eye hurts because it is dry and sticky, on the other hand the inflammation of the lacrimal gland (also called dacryoadenitis) causes an unpleasant feeling of pressure, which is often associated with pain. Dry eyes, however, must not only be caused by a blockage of the tear ducts: Dry air, computer work or excessive computer gaming as well as tobacco smoke can also dry out the eyes and lead to an unpleasant burning sensation and pain. Another adnex or eye appendage is the eyelids.
Pain on the eyelids is usually caused by the underlying structures, such as an inflamed conjunctiva or likewise blocked glands. Often, however, the pain appears on the eyelid and not at the actual point of origin. Therefore, in the case of pain on the eyelid, damage to the other adnexae must always be taken into consideration.
