Uveitis is an inflammation of the eye that infects one or more of three parts from which uvea, the middle ocular membrane, consists.
We can think of an eye as a sphere that is made out of three layers: external layer is sclera with cornea, internal layer is retina and between the two of them is uvea. Uvea consists of three parts:
- Iris (the colorful part of the eye)
- Ciliary or radial body (responsible for making eyewash and eye accomodation)
- Choroid (a tissue with a lot of blood vessels, it is located underneath the cornea, it has a nutritional role)
Uvea feeds the eye through the blood vessels and that is why it’s infection calls the whole eye nutrition into question. Uveitis can threaten one’s life more and it is more serious than most of the other eye diseases. Problems that are related to uveitis are usually underestimated, as from general population, also from ophthalmologists, eye doctors. A very small number of people know that uveitis is third most common cause of blindness.
Autoimmune uveitis is the most common one. Uveitis has a tendency to reoccur.
Causes
Around 60 different causes can be responsible for uveitis occurence and that is why “detective work” on finding the cause for uveitis is a strenuous and expensive process for every patient. This detective work looks more like diagnostic procedure in internal medicine than in ophthalmology. And because of that a very small number of ophthalmologists is specialized for uveitis. Besides, treating some forms of uveitis calls for systemic therapy (non-steroidal anti-inflammatory medication, steroids and / or immunomodulators, chemotherapy) which also repels a lot of ophthalmologists from this area.
By the causes uveitis is classified into these groups:
1. Infectious
- Bacterial (tuberculosis, syphilis, leprosy, borreliosis, …)
- Viral (varicella virus, herpes simplex virus, HIV, cytomegalovirus, …)
- Fungi (candidiasis, aspergillosis, histoplasmosis)
- Protozoa (toxoplasmosis)
- Parasites (toxocariasis, cysticercosis)
2. Noninfectuous and associated with systemic diseases
- Ankylosing spondylitis
- Reiter’s syndrome
- Psoriatic arthritis
- Juvenile chronical arthritis
- Behcet’s disease
- Sarcoidosis
- Vogt-Koyanagi-Harada syndrome
3. Specific idiopathic (unknown cause) entities
- Fuchs uveitis, pars planitis
- Idiopathic vasculitis, vitritis
- Sympathetic ophthalmia
4. Nonspecific entities of unknown cause – uveitis that cannot be enlisted in one of the three groups
Classification
Other than by causes, uveitis can be classified by:
- Anatomical location front (anterior), middle (intermediate), rear (posterior), complete (panuveitis), peripheral (pars planitis)
- Clinical course (duration): acute, subacute i chronical
- Pathological-histological findings: granulomatous and nongranulomatous
Uveitis heredity
Uveitis is not a hereditary disease, so it doesn’t occur typically in some families. However, some persons have increased probability of getting uveitis because of a gene they carry. Some types of uveitis are related to genes like HLA B27 and HLA A29.
Uveitis symptoms
Anterior uveitis
Anterior uveitis is inflammation of the iris and or radial body (iritis, cyclitis and iridocyclitis). It can be acute if it’s duration is short or chronic if it’s duration is more than three months.
Symptoms of the anterior acute uveitis are: pain, redness of the eye, photophobia (the patient is sensitive to light), tearing, blurred vision.
With chronic uveitis we find a calm, white eye.
Signs that doctor finds while examining the eye are: redness of the conjunctiva, blurred retina and eyewash because of the deposition of inflammatory cells and proteins, blood in anterior eye chamber (hyphema), adhesions (synechiae) of iris and pupil, increased blood supply of the iris which causes it to change it’s colour to a dirty green or dirty grayish green.
Intermedijate uveitis
The main symptom is “floaters” in front of the eye (because of inflammatory elements in the vitreous cavity) and blurred vision.
Posterior uveitis
Posterior uveitis is usually painless, but more dangerous because it causes blindness more often. “Floaters” and blurred vision are also it’s characteristics.
Treatment
In treating uveitis the tendency is to achieve:
- Unpleasentness and pain relief
- Prevention of losing eyesight because of the disease or it’s complications
- Treating the cause if it is known and when the treatment is possible
As the causes of uveitis are very different, the treatment of some types is different as well.
The treatment is, therefore, symptomatic and causal.