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Disease Profile

Pars planitis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Intermediate uveitis; Peripheral retinal inflammation; Vitritis


Pars planitis is a disease of the eye that is characterized by inflammation of the narrowed area (pars plana) between the colored part of the eye (iris) and the choroid. This may lead to blurred vision; dark, floating spots in the vision; and progressive vision loss. As the condition advances, cataracts, retinal detachment, or macular edema (fluid within the retina) may develop. Pars planitis most often affects young men and is generally not associated with any other disease or symptoms (idiopathic); however, it can be associated with other autoimmune conditions such as multiple sclerosis and sarcoidosis. Treatment typically includes corticosteroid drugs, immunosuppressive medications, and/or surgery.[1][2][3]


Pars planitis is characterized by inflammation of the narrowed area (pars plana) between the colored part of the eye (iris) and the choroid. This may lead to blurred vision; dark, floating spots in the vision; and progressive vision loss.[1][2] Approximately 80% of cases are bilateral (affecting both eyes), although one eye is typically more affected than the other. As the condition advances, cataracts, retinal detachment, or macular edema (fluid within the retina) may develop.[3]


The exact underlying cause of pars planitis is unknown. Scientists suspect that it is an autoimmune condition in which the body's immune system mistakenly attacks healthy tissues (certain parts of the eyes, in this case). This is further supported by the fact that pars planitis is sometimes associated with other autoimmune conditions such as multiple sclerosis and sarcoidosis.[2][1]

Although most cases occur sporadically in people with no family history of the condition, pars planitis can rarely affect more than one family member. In these cases, there may be a genetic component; however, a disease-causing gene and specific inheritance pattern have not been identified.[4]


Pars planitis is typically diagnosed based on a specialized eye examination. During the exam, the ophthalmologist will typically see clusters of white blood cells trapped within the eyeball that are called snowballs (or "inflammatory exudate"). If these clusters are located on the pars plana, they are known as snowbanks. Snowbanks are considered a "hallmark" sign of pars planitis.[1][2]

It is often recommended that people over age 25 with pars planitis have an MRI of their brain and spine to rule out multiple sclerosis.[5]


The first approach to treating pars planitis is corticosteroid eye drops or injections near the eye to control inflammation. Non-steroidal anti-inflammatory drugs (NSAIDs, including aspirin) or steroid medications (such as prednisone) can be taken by mouth. If these strategies are not successful, other medications may be given to reduce the body's immune response (medications called immunosuppressants, such as methotrexate).[2][3]

If medications are not effective, surgery may be considered. Cryotherapy has been performed in affected people to remove eye tissue that has inflammation. Although this surgery has been shown to be effective in restoring clarity of vision, there are concerns that it may cause damage to other parts of the eye. Another surgery, known as vitrectomy, can be done to remove cloudy fluid (vitreous humor) from the eye.[6][2]

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

  • Adalimumab(Brand name: Humira) Manufactured by AbbVie Inc.
    FDA-approved indication: September 2018, adalimumab (Humira) received expanded approval for the treatment of non-infectious intermediate, posterior, and panuveitis to include pediatric patients 2 years of age and older. It was approved for use in adults with non-infectious intermediate, posterior, and panuveitis in June 2016.
    National Library of Medicine Drug Information Portal
    Medline Plus Health Information


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Organizations Providing General Support

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
      • The American Academy of Ophthalmology provides information about pars planitis. Click on the link to view the information related to this topic.

        In-Depth Information

        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Pars planitis. Click on the link to view a sample search on this topic.


          1. Pars Planitis. NORD. 2008; https://rarediseases.org/rare-diseases/pars-planitis/.
          2. Robert H Janigian, Jr, MD. Intermediate Uveitis. Medscape Reference. August 2013; https://emedicine.medscape.com/article/1208794-overview.
          3. Michael Tolentino, MD; Reza Dana, MD, MPH, MSc. Retinal vasculitis associated with primary ocular disorders. UpToDate. November 2014; Accessed 6/22/2015.
          4. PARS PLANITIS. OMIM. 2001; https://www.omim.org/entry/606177.
          5. Uveitis. MedlinePlus. September 2014; https://www.nlm.nih.gov/medlineplus/ency/article/001005.htm.
          6. Prieto JF, Dios E, Gutierrez JM, Mayo A, Calonge M, Herreras JM. Pars planitis: epidemiology, treatment, and association with multiple sclerosis. Ocular immunology and inflammation. 2001; 9:93-102. https://www.ncbi.nlm.nih.gov/pubmed/11449325. Accessed 4/3/2012.

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