Uveitis refers to the inflammation of the uveal tract of the eye.
The symptoms of anterior uveitis are as below.
Photophobia is due to the reactive spasm of the inflamed muscles of the iris; whereas spasm of the ciliary muscles leads to brow pain. Visual acuity is only decreased in severe cases associated with hypopyon.
The signs of anterior uveitis include the following.
Ciliary flush results from perilimbal conjunctival injection. Spasm of the ocular sphincter muscle causes miosis. Anterior chamber cells are infact white blood cells that are seen in the anterior chamber; whereas anterior chamber flare refers to the presence of protein precipitates in the anterior chamber. Both of these manifestations are secondary to inflammation. Hypopyon results from the collection of neutrophilic exudates inferiorly in the anterior chamber. Keratic precipitates are only occasionally present and are seen as clumps of cells on the corneal epithelium. Iritis typically reduces the intraocular pressure because the inflammation of the ciliary body causes decreased production of the aqueous humor. However, there is an exception to this rule in which severe iritis, or iritis resulting from herpes simplex and herpes zoster may cause an inflammatory glaucoma.
Intermediate uveitis usually has an insidious onset. Blurred vision accompanied by vitreous floaters are usually present. Initially, the symptoms are usually unilateral but inflammatory changes are often bilateral and asymmetric. Vitreous cells, condensations and “snowballs” are often seen on examination, the latter being vitreous aggregates of inflammatory cells. Posterior segment snowbanking is also seen.
Posterior uveitis is usually painless. This is because the choroid has no sensory innervation. Conjunctival or scleral injection is often not present. Visual acuity may be decreased. Floaters (due to debris and inflammatory cells) are present. Vitreous cells and opacities may also be seen. In certain cases, hypopyon may also form.
The diagnosis of uveitis is usually clinical and no specific tests are needed. Intraocular pressure measurement may be required to rule out glaucoma. Tests may be performed to determine the underlying cause of uveitis (e.g. infections, autoimmune causes and malignancies).
The treatment of anterior uveitis consists of the following components.
The treatment strategies for intermediate uveitis include the following.
Posterior uveitis is treated with steroids which may be given through retrobulbar or systemic route.
With proper treatment, the prognosis of uveitis is usually good.
Untreated anterior uveitis may lead to inflammatory glaucoma and the formation of posterior synechiae and peripheral anterior synechiae. The former refers to adhesions of posterior iris to anterior lens capsule whereas the latter refers to adhesions of the iris to the cornea. Cataracts and band keratopathy may also occur.
Untreated intermediate uveitis can lead to cystoid and macular edema in up to 30% of the cases. Cataract and glaucoma may also develop in some cases.
Temporary or permanent visual impairment or even blindness may occur from uveitis in severe cases .
The etiological factors depend upon the type of uveitis.
Anterior uveitis is usually idiopathic. It may be the result of several connective tissue diseases. Several causes of anterior uveitis are related to HLA-B27 and include reactive arthritis, ankylosing spondylitis, psoriatic arthritis and inflammatory bowel disease . Causes unrelated to HLA-B27 include juvenile idiopathic arthritis, sarcoidosis, ocular trauma, ocular surgery and infections (such as toxoplasmosis, syphilis, Lyme’s disease, herpes simplex virus, herpes zoster virus and tuberculosis) .
Intermediate uveitis is mostly idiopathic. Secondary causes such as sarcoidosis, Lyme’s disease and multiple sclerosis may also cause intermediate uveitis  . Intermediate uveitis is often associated with anterior uveitis.
Posterior uveitis results from infections, autoimmune mechanisms and malignancies. The infection may be bacterial, viral, fungal or parasitic. The most common cause of posterior uveitis is parasitic infection (toxoplasmosis). Bacterial causes include syphilis and tuberculosis whereas viral causes are herpes simplex virus, cytomegalovirus (in acquired immunodeficiency syndrome). Fungal infections leading to posterior uveitis include histoplasmosis and candidiasis. Behcet’s disease is an autoimmune cause of posterior uveitis. It includes a triad of oral ulcers, genital ulcers and posterior uveitis . Malignant melanoma and metastatic lesions can also cause posterior uveitis.
Uveitis is affects around 1 in 4500 people worldwide. Adults of age 20 to 60 years are usually affected whereas children are relatively spared. Anterior uveitis is the most common type of uveitis and accounts for 50 to 90% of the cases in the United States and around 30 to 50% in Asia .
The clinical features and manifestations of the disease result from the infection of the various parts of the uveal tract.
Uveitis results from multifactorial causes and there are no specific preventive measures against it.
If any causal infection has developed, prompt treatment is mandatory to prevent the progression of the disease and involvement of the eye(s).
Uvetis refers to the inflammation of the uveal tract of the eye. Depending upon the regions involved, may be classified into 3 types; namely anterior uveitis, intermediate uveitis and posterior uveitis .
Anterior uveitis is usually unilateral and can be defined as the inflammation of the iris (iritis). Iritis is usually accompanied by cyclitis (inflammation of the ciliary body). When both the iris and the ciliary body are involved, the condition is called iridocyclitis.
Intermediate uveitis refers to the inflammation of the vitreous; while inflammation of the choroid is known as posterior uveitis.