Introduction
The eye is one of the smallest organs in our body, weighing only 7.5g and with a diameter of 2.3cm. Nevertheless, it can lead to various diseases, which can sometimes cause unpleasant to severe pain. Fortunately, not all parts of the eye can be painful, and most often cornea, sclera, and uvea are affected.
However, there are also appendages or adnexes in the periphery of the eye, such as glands, eyelids and eye muscles, which can cause pain. The conjunctiva forms the anterior boundary of the eye, it pulls inwards at the edge of the eyelid and downwards and ends directly at the cornea of the eyeball after a fold of the eyelid. You can see the conjunctiva when you pull down an eyelid with your hand, because it lines the eyelid from the inside.
In this position, the conjunctiva is always exposed to a variety of external stimuli and becomes inflamed correspondingly quickly. One speaks then of a conjunctivitis or also conjunctivitis. In addition to pain, itching, redness, burning, foreign body sensation and increased lacrimation also occur.
Occasionally conjunctivitis also causes pain in the corners of the eyes. Conjunctivitis can have a variety of causes: In addition to mechanical influences such as dusty or smoky surroundings, dry air is considered the main trigger for conjunctivitis. However, so-called dry conjunctivitis can also be caused by reduced production or increased drainage of the tear film.
This can be the case if the glands are blocked or if the eyelid is bulging out due to ectropion. As a result, the tear film cannot be kept on the eye and the eye dries out. Conventional conjunctivitis is relatively common, but can also have more serious causes, such as bacterial or viral infestation.
Bacterial colonization is critical in that it produces pus as well as pain. In the absence of treatment, it may be necessary to remove the eye in the final stage. While an ectropion refers to the “outward tilting” of the eyelid, an inward rolled up eyelid is called entropion.
An entropion can cause pain, as the edge of the eyelid grinds along the anterior edge of the eye. If the cornea is marked with fluorescent markings, the damaged areas can be seen very clearly, which can cause pain as well as a reduction in visual acuity. Furthermore, pain occurs in case of inflammation of the sclera of the eye.
The sclera is located at the back of the eyeball towards the eye sockets, its inflammation is called scleritis. Scleritis is usually accompanied by severe pain and in half of the cases has a systemic – i.e. affecting the entire body. An inflammation causes swelling of the sclera.
Since the sclera lies against the bony orbit of the eye and therefore cannot move in any direction, this pressure has a direct effect on the eyeball. This leads to a pressure pain or general eye pain. Pain can also be caused by uveitis.
Uveitis is an inflammation of the uvea, the skin of the eye. This consists of several parts, which can all be affected to the same extent, namely the iris, corpus cilliare and choroidea. Uveitis is anatomically divided into anterior, intermedial and posterior uveitis.
In anterior uveitis, the anterior part of the eye including the anterior chamber of the eye is affected. An anterior uveitis can occur both chronically and acutely. Typical are sometimes very severe pain, redness of the eye as well as a reduction in visual acuity and photophobia. 60-70% of all uvetides affect the anterior chamber of the eye. Middle and posterior uveitis usually proceeds without symptoms and also painlessly, which does not make it less dangerous: Possible complications are cataracts and in the worst case blindness.
