Uveitis is an inflammation of one or all parts of the uveal tract or the vascular area between the retina and the sclera of the eye. The anterior part of the uveal tract (UT) consists of the iris and ciliary body. Irritation of this segment, or anterior uveitis, leads to acute pain and photophobia. Inflammation of the posterior part of the UT, including the choroid, retina, and retinal vessels, carries the risk of vision loss (Chan & Chee, 2019). Uveitis of all types occurs in both children and adults, and its etiology is most often idiopathic. With anterior uveitis, inflammation of the iris and ciliary body is observed. Acute anterior uveitis can be associated with HLA-B27-related diseases or viral infections. The article Demystifying Viral Anterior Uveitis: A Review examines clinical features, differential diagnoses, and variable manifestations of viral anterior uveitis.
In anterior uveitis, the primary locus of inflammation is in the anterior segment of the eye. It includes iritis (inflammation in the anterior chamber only) and iridocyclitis (inflammation in the anterior chamber and anterior vitreous surface). Causes of viral anterior uveitis include herpesvirus infection (herpes simplex virus (HSV), varicella-zoster virus (VZV), and cytomegalovirus (CMV) (Chan & Chee, 2019). Anterior uveitis, which tends to have a pronounced symptomatic course, especially in acute form, usually manifests itself with eye pain, redness, photophobia, and decreased visual acuity. Conjunctival hyperemia adjacent to the cornea may occur as well. Corneal precipitates, cells, opacity in the anterior chamber, as well as posterior synechiae, can be detected under a slit lamp. In severe anterior uveitis, leukocytes can accumulate in the anterior chamber. Anterior uveitis can cause redness, keratin precipitation on the corneal endothelium, as well as the presence of leukocytes and inflammation in the anterior chamber of the eye.
Serious complications of uveitis include profound and irreversible loss of vision, especially if the uveitis was not recognized or the wrong therapy was prescribed. The most common complications include cataracts, glaucoma, retinal detachment, retinal, optic, or iris neovascularization, cystic macular edema, and hypotension (Chan & Chee, 2019). The diagnosis of anterior uveitis is made after the detection of cells in the anterior chamber. They are best visualized on a slit lamp by directing a narrow beam of light onto the anterior chamber in a dark room.
Treatment of active inflammation usually involves the use of topical corticosteroids, as well as periocular or intraocular injections in conjunction with cycloplegic and mydriatic drugs. Antimicrobial drugs are used to treat viral anterior uveitis (Chan & Chee, 2019). Severe or chronic cases may require systemic corticosteroids, systemic noncorticosteroid immunosuppression, laser phototherapy, or surgical removal of the vitreous humor. Pharmacotherapy in a large number of cases has a general and anti-inflammatory orientation.
To conclude, herpes simplex virus (HSV) is the main causative agent of anterior uveitis. Varicella-zoster virus (VZV) is less commonly the causative agent, but the risk of developing anterior uveitis caused by VZV increases with age. The complexity of effective treatment of uveitis is due to the fact that even with the most thorough examination, it is not always possible to identify their true cause. In all cases of anterior uveitis, local treatment is prescribed in the form of eye drops and ointments. If necessary, injections are also carried out under the conjunctiva and into the periocular space. In some cases, funds are required to reduce increased intraocular pressure.
Reference
Chan, N. S. W., & Chee, S. P. (2019). Demystifying viral anterior uveitis: A review. Clinical and Experimental Ophthalmology, 47(3), 320-333.