Uveitis is a general term describing a group of inflammatory diseases affecting the vascular layer of the eye. These diseases can reduce vision or lead to an almost complete loss of it.
The vascular layer of the eye (uvea or uveal tract) is located between the sclera (the white outer layer of the eye) and the retina (inner layer). It consists of the iris, the ciliary body, and the choroid (the vascular layer itself). However, in uveitis, the lens, retina, vitreous body, and optic nerve may be involved, resulting in decreased vision or blindness.
The average age of patients with uveitis is 20 to 59 years. However, it can occur at any age.
Types of uveitis
Uveitis can be acute (up to 3 months), chronic (lasting longer and reoccurs within 1-2 months after treatment), or recurrent (the interval between exacerbations is more than three months).
Depending on the localization, there are:
- Anterior uveitis (iritis) is an inflammation in the anterior part of the vascular layer (iris). It is the most favorable and common uveitis.
- Intermediate uveitis (cyclitis). The center of the inflammation in this uveitis is often in the ciliary or vitreous body. This uveitis is associated with several diseases, including sarcoidosis and multiple sclerosis.
- Posterior uveitis is the least common form of uveitis. It affects the back of the eye, often including the retina and choroid. It is often called choroiditis or chorioretinitis.
- Panuveitis is a generalized form in which all parts of the choroid are affected. Behçet's disease is one of the most well-known forms of panuveitis, and it severely damages the retina.
Causes of uveitis
Uveitis can be caused by:
- An attack of the body's immune system (autoimmune inflammation).
- Infections or tumors occurring inside the eye or in other parts of the body.
- Hemorrhage in the eye, trauma, or surgery.
- Toxins that can enter the eye.
Frequently it is not possible to establish the exact cause.
Among the diseases that can be associated with uveitis are:
- Ankylosing spondylitis.
- Behçet's syndrome.
- Cytomegalovirus retinitis.
- Herpes zoster infections.
- Kawasaki disease.
- Multiple sclerosis.
- Reactive arthritis.
- Rheumatoid arthritis.
- Ulcerative colitis.
Uveitis affects one or both eyes. Symptoms of uveitis may develop suddenly or gradually and include:
- Blunt pain in or around the eye, which may increase with focusing;
- red eyes;
- sensitivity to light (photophobia);
- constriction of the pupil of the affected eye and lack of its response to light;
- blurred vision;
- increased number of dark, floating spots ("eye floaters");
- loss of peripheral vision (the ability to see objects at the sides).
Complications of uveitis
You are more likely to have complications if:
- You are over 60 years old;
- You have long-term (chronic) uveitis;
- You have less common types of uveitis (intermediate or posterior uveitis).
The most common complications of uveitis include:
- Glaucoma is damage to the optic nerve that connects the eye and brain due to increased intraocular pressure (IOP). It is important to note that corticosteroids cause an increase in IOP;
- A cataract is the loss of transparency of the lens;
- Cystoid macular edema is swelling of the central part of the retina, which is responsible for visual acuity. It can affect people with chronic or posterior uveitis;
- epiretinal membrane;
- retinal detachment — this is when the retina begins to detach from the blood vessels that supply it with oxygen and nutrients;
- Posterior synechiae are adhesions between the iris and the lens caused by inflammation;
- Damage of the optic nerve disc and its edema;
- Persistent loss of vision;
- ocular hypotony.
Diagnosis of uveitis
Diagnosing uveitis involves a thorough examination and recording a complete medical history of the patient. Laboratory tests may be necessary to rule out infection or autoimmune disorder (antibody tests).
Ophthalmic exams include:
- Measurement of visual acuity using special charts.
- Measurement of intraocular pressure (tonometry).
- Examination of pupil response.
- Examination with a slit lamp. The doctor examines the front and back parts of the eye more closely.
- Gonioscopy is an examination of the angle of the anterior chamber with a contact lens.
- Funduscopy (examination of the fundus of the eye). The pupil is dilated with eye drops, and then the doctor uses a special lens to examine the retina.
- Ultrasound of the eye is used to determine the condition of the ciliary body, vitreous body, and retina.
- Perimetry is an examination of the visual fields.
If the diagnosis is difficult, optical coherence tomography, fluorescence angiography, and electroretinography may be required.
To find the cause of uveitis, you may need to consult other specialists such as a rheumatologist, allergist/immunologist, neurologist, phthisiatrician.
The main treatment for uveitis is steroid medications (corticosteroids). They reduce the inflammation inside the eye.
Depending on the type of uveitis, different types of steroid drugs are recommended. For example:
- Eye drops are mainly used for anterior uveitis;
- Injections, pills, and capsules (implanted into the eye) are commonly used to treat intermediate and posterior uveitis.
In severe cases, corticosteroids are prescribed systemically, and other immunosuppressant drugs (methotrexate, adalimumab) are added.
Cycloplegic and mydriatic drugs are also prescribed (to prevent posterior synechiae formation). In bacterial uveitis antimicrobial drugs are prescribed, in viral uveitis antiviral drugs are used. In some cases, surgery (vitrectomy or implantation of a steroid capsule) is performed.
In most cases, uveitis has a good prognosis with early detection and appropriate treatment. Identifying the cause of uveitis is necessary to prevent subsequent recurrences. It is also important because of the significant morbidity and mortality associated with some specific systemic diseases that may cause uveitis
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