Uveitis

What is uveitis?

Uveitis is an inflammatory process affecting the uvea, the thin vascular tunic of the eye that is interposed between the external ocular membrane (sclera and cornea) and the retina.

Although the term "uveitis" expresses the sole inflammation of the uvea, very often this word is improperly used to indicate inflammatory processes affecting other ocular structures, such as for example retina, sclera and cornea. The popular imprecise use of the term uveitis is soon explained by the fact that the so-called "pure" inflammations (which exclusively concern the uvea) are rather rare: more often, in fact, uveal infections tend to expand until they involve the adjacent structures, such as precisely the sclera, the retina and the ocular endothelium.

Uveitis - like most of the inflammations affecting the eye - requires immediate intervention by medical help: this is because an affection of this type can lead to extremely serious complications. Just think, for example, that 10-15% of patients with uveitis become blind.

Let's be clear

Each infection involving a single ocular structure is qualified with a precise term:

• Scleritis: inflammation of the sclera
• Keratitis: inflammation of the cornea
• Keratoconjunctivitis: corneal and conjunctiva inflammation
• Retinitis: inflammation of the retina
• Iritis: inflammation of the iris
• Iridocyclitis: inflammation of the iris and ciliary bodies

Types of uveitis

We have seen that the uvea is the ocular membrane interposed between the external tunic of the eye (sclera and cornea) and the nerve tunic (retina). More precisely, the uvea is an ocular structure consisting of three very important sections: choroid, ciliary and crystalline body. According to the ocular element involved in inflammation, several types of uveitis can be distinguished:

• Anterior uveitis: an inflammatory process affecting the iris and the ciliary body or just the iris
• Intermediate uveitis: inflammation limited to the ciliary body
• Posterior uveitis: inflammation (inflammation) of the choroid
• Panuveite (or more simply uveitis): inflammation involving all three structures of the uveal tract

Although this classification is extremely precise and limited to a particular leaflet of the uveal tract, we recall once again that in most cases the uveitis tends to expand, involving more anatomical ocular structures (sclera, cornea, retina, etc.).

Causes

A second classification of uveitis can be performed according to the triggering causes. For this purpose, the endogenous variant of uveitis is distinguished from the exogenous one.

The table shows the most common causes of uveitis:

Causes of exogenous uveitis

• Brucellosis
• Perforating wounds
• Dental granulomas
• Herpetic infections
• Toxoplasma infections
• Leptospirosis
• Lyme disease
• Sarcoidosis
• Syphilis
• Surgical interventions
• Tuberculosis
• Corneal ulcers

Causes of endogenous uveitis

• Systemic lupus erythematosus
• Behçet's disease
• Kawasaki disease
• Rheumatic diseases
• Local immunological reactions
• Multiple sclerosis
• Fuchs syndrome (rare hereditary disease manifested by corneal edema)
• Ankylosing spondylitis
• Eye tumor

In recent years it has been discovered that even cigarette smoking could increase the risk of uveitis: this is because smoking goes to alter (and weaken) the efficiency of the immune system.

Although numerous potential causes of uveitis have been identified, it is often not possible to understand their precise origin.

Symptoms

Very often, patients suffering from uveitis become suspicious of the disease starting from the very first symptoms: the eye becomes very sensitive and intolerant to light, is evidently red (ocular hyperaemia), and vision is blurred.

Even the perception of spots in front of the eyes is a rather frequent symptom accused by affected patients. In the intermediate uveitis, for example, the appearance of vitreous moving bodies (which in technical terms is called myopia ) is an obvious warning signal.

Most often, intermediate and posterior uveitis do not cause unsustainable eye pain. In chronic anterior uveitis, the disease can even go unnoticed because the symptoms are not so fierce, and the eye - at least apparently - is in good health even in the presence of severe inflammation of the uveal tract.

Depending on the causative agent, the symptoms with which the uveitis occurs may involve only one eye or both.

The typical symptoms of uveitis do not always appear in a sudden and evident way: sometimes, in fact, the onset of the disease is subtle and ambiguous precisely because it does not develop any characteristic symptom that suggests a first diagnostic hypothesis.

Complications

In many patients, uveitis is particularly difficult to eradicate; so much so that very often uvea inflammations tend to become chronic.

The chronic course of uveitis is the main cause of complications, such as in particular:

• Increased intraocular pressure (glaucoma)
• Blindness
• Damage to the optic nerve
• Swelling / detachment of the retina
• Inflammation of the cornea
• Crystalline opacity (cataract)

Given the complications and the danger of the disease, it is therefore necessary to undergo an ocular examination as soon as possible: in this way, it will be possible to ascertain the uveitis in an unequivocal way to undertake a specific therapy as soon as possible.