Intermediate uveitis is a form of

uveitis Uveitis () is inflammation of the uvea, the pigmented layer of the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea. The uvea consists of the middle layer of pigmented vascular structures of the eye and ...

localized to the vitreous and peripheral

retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...

. Primary sites of inflammation include the vitreous of which other such entities as pars planitis, posterior cyclitis, and hyalitis are encompassed. Intermediate uveitis may either be an isolated eye disease or associated with the development of a systemic disease such as

multiple sclerosis Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This d ...

sarcoidosis Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly af ...

. As such, intermediate uveitis may be the first expression of a systemic condition. Infectious causes of intermediate uveitis include

Epstein–Barr virus The Epstein–Barr virus (EBV), formally called ''Human gammaherpesvirus 4'', is one of the nine known human herpesvirus types in the herpes family, and is one of the most common viruses in humans. EBV is a double-stranded DNA virus. It is b ...

infection,

Lyme disease Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the ''Borrelia'' bacterium, which is spread by ticks in the genus ''Ixodes''. The most common sign of infection is an expanding red rash, known as erythema migran ...

HTLV-1 Human T-cell lymphotropic virus type 1 or human T-lymphotropic virus (HTLV-I), also called the adult T-cell lymphoma virus type 1, is a retrovirus of the human T-lymphotropic virus (HTLV) family that has been implicated in several kinds of diseas ...

virus infection,

cat scratch disease Cat-scratch disease (CSD) or felinosis is an infectious disease that most often results from a scratch or bite of a cat. Symptoms typically include a non-painful bump or blister at the site of injury and painful and swollen lymph nodes. People m ...

, and

hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...

. Permanent loss of vision is most commonly seen in patients with chronic

cystoid macular edema Macular edema occurs when fluid and protein deposits collect on or under the macula of the eye (a yellow central area of the retina) and causes it to thicken and swell (edema). The swelling may distort a person's central vision, because the macul ...

(CME). Every effort must be made to eradicate CME when present. Other less common causes of visual loss include

retinal detachment Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blin ...

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye rem ...

band keratopathy Band keratopathy is a corneal disease derived from the appearance of calcium on the central cornea. This is an example of metastatic calcification, which by definition, occurs in the presence of hypercalcemia. Signs and symptoms Signs and sympto ...

cataract A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble w ...

vitreous hemorrhage Vitreous hemorrhage is the extravasation, or leakage, of blood into the areas in and around the vitreous humor of the eye. The vitreous humor is the clear gel that fills the space between the lens and the retina of the eye. A variety of conditio ...

epiretinal membrane Epiretinal membrane or macular pucker is a disease of the eye in response to changes in the vitreous humor or more rarely, diabetes. Sometimes, as a result of immune system response to protect the retina, cells converge in the macular area as t ...

and

choroidal neovascularization Choroidal neovascularization (CNV) is the creation of new blood vessels in the choroid layer of the eye. Choroidal neovascularization is a common cause of neovascular degenerative maculopathy (i.e. 'wet' macular degeneration) commonly exacerbated ...

Signs and symptoms

Clinical signs include redness of the eye, pain, blurring of vision,

photophobia Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of ...

and

floater Floaters or eye floaters are sometimes visible deposits (e.g., the shadows of tiny structures of protein or other cell debris projected onto the retina) within the eye's vitreous humour ("the vitreous"), which is normally transparent, or betwee ...

s. However, some individuals, particularly children, can present with few to no symptoms.

Associated conditions

Associations of the disease with such entities as

, or

inflammatory bowel disease Inflammatory bowel disease (IBD) is a group of inflammation, inflammatory conditions of the colon (anatomy), colon and small intestine, Crohn's disease and ulcerative colitis being the principal types. Crohn's disease affects the small intestine a ...

suggest an autoimmune component in at least a subset of patients. The clustering of familial cases has led to the investigation of

human leukocyte antigen The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of th ...

(HLA) associations. The inciting event appears to be peripheral retinal perivasculitis and vascular occlusion leading to ocular inflammation, vitritis and snowbank formation. The etiology of the antigenic stimulus is not clear and may be either vitreal or perivascular in nature. It is evident that genetics plays some role in the pathophysiology of intermediate uveitis, but the importance remains unclear.

Pathophysiology

Pars planitis is considered a subset of intermediate uveitis and is characterized by the presence of white exudates (snowbanks) over the

pars plana The ''pars plana'' (also known as ''orbicularis ciliaris'' ) (Latin: flat portion) is part of the ciliary body in the uvea (or vascular tunic), the middle layer of the three layers that comprise the eye. It is about 4 mm long, located near ...

or by aggregates of inflammatory cells in the vitreous (snowballs) in the absence of an infectious or a systemic disease. Some physicians believe that patients with pars planitis have worse vitritis, more severe

macular edema Macular edema occurs when fluid and protein deposits collect on or under the macula of the eye (a yellow central area of the retina) and causes it to thicken and swell ( edema). The swelling may distort a person's central vision, because the macu ...

, and a guarded prognosis compared to other patients with intermediate uveitis.

Treatment

Peri-ocular injection of

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...

s (injection of corticosteroids very close but not into the eye). In resistant cases oral administration of corticosteroids,

immunosuppressive drug Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified into ...

s, and laser or cryotherapy of the involved area may be indicated. Steroid implants have been explored as a treatment option for individuals with non-infectious uveitis. Research comparing

fluocinolone acetonide Fluocinolone acetonide is a corticosteroid primarily used in dermatology to reduce skin inflammation and relieve itching. It is a synthetic hydrocortisone derivative. The fluorine substitution at position 9 in the steroid nucleus greatly enhances ...

intravitreal implants to standard-of-care treatments (

prednisolone Prednisolone is a steroid medication used to treat certain types of allergies, inflammatory conditions, autoimmune disorders, and cancers. Some of these conditions include adrenocortical insufficiency, high blood calcium, rheumatoid arthrit ...

with immunosuppressive agents) found that while the steroid implant treatment possibly prevents the recurrence of uveitis, there may be adverse safety outcomes, such as the increased risk for needing

cataract surgery Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye (also called "crystalline lens") that has developed an opacification, which is referred to as a cataract, and its replacement with an intraocu ...

and surgery to lower

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated to ...

Epidemiology

Although intermediate uveitis can develop at any age, it primarily afflicts children and young adults. There is a bimodal distribution with one peak in the second decade and another peak in the third or fourth decade. In the United States the proportion of patients with intermediate uveitis is estimated to be 4-8% of uveitis cases in referral centers. The

National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...

reports a higher percentage (15%), which may indicate improved awareness or the nature of the uveitis referral clinic. In the pediatric population, intermediate uveitis can account for up to 25% of uveitis cases.

References

{{DEFAULTSORT:Intermediate Uveitis Disorders of iris and ciliary body