• Disease Overview
  • Synonyms
  • Signs & Symptoms
  • Causes
  • Affected Populations
  • Disorders with Similar Symptoms
  • Diagnosis
  • Standard Therapies
  • Clinical Trials and Studies
  • References
  • Programs & Resources
  • Complete Report

Pars Planitis

Print

Last updated: October 27, 2008
Years published: 1989, 1996, 2004, 2008


Acknowledgment

NORD gratefully acknowledges Dr. Patricio A. Pacheco, Bsc, MD, MRCOphth, Senior Clinical Fellow /Uveitis Service, Moorfields Eye Hospital, London, UK for assistance in the preparation of this report.


Disease Overview

Although pars planitis is generally benign, there can be significant vision loss in extreme cases. It is an immunological disorder of the eye characterized by inflammation of a part of the uvea, the layer of tissue between the sclera and the retina, the membranes protecting the eyeball. The uvea, in turn, is made up of three portions: the iris, the ciliary body, and the choroid. In addition, the uvea contains many of the blood vessels that supply the eye.

The pars plana is a narrow section of the ciliary body, inflammation of which is known as pars planitis. In association with the inflammation or immunological response, fluid and cells infiltrate the clear gelatin-like substance (vitreous humor) of the eyeball, near the retina and/or pars plana. As a result, swelling of the eye or eyes can also occur, but more importantly blurred vision and progressive increase in the vision of floaters is reported as main symptoms by patients suffering this condition as a result of the infiltration of the vitreous humor.

The inflammation occurs in the intermediate zone of the eye; that is, between the anterior part(s) of the eye (iris) and the posterior part(s), the retina and/or choroid. It has therefore been designated as one of the diseases of a family of intermediate uveitis.

In some cases, the disturbance of vision may be slightly progressive.

  • Next section >
  • < Previous section
  • Next section >

Synonyms

  • Intermediate Uveitis (UI)
  • Peripheral Retinal Inflammation
  • PP
  • Vitritis
  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Signs & Symptoms

The symptoms of pars planitis include blurred vision and dark floating spots that intrude upon clarity of eyesight. Swelling can occur inside the eye, particularly on the peripheral retina or macula that may lead to decreased vision. Glaucoma may occur as well.

The clinical picture may be complicated by cataracts, retinal detachment, or fluid within the retina (macular edema)

More often the examining ophthalmologist (specialist in diseases of the eye) will see clusters of white blood cells trapped within the eyeball that are called snowballs. The term physicians may use for these is inflammatory exudate. These are clusters of white blood cells trapped within the eyeball. If these clusters are located on the pars plana, they are known as snowbanks.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Causes

Pars planitis is thought to be an autoimmune disorder. An autoimmune reaction causes the inflammation that is thought to cause symptoms of this disorder.

Autoimmune disorders are caused when the body’s natural defenses against foreign or invading organisms (e.g., antibodies) begin to attack healthy tissue for unknown reasons. In rare cases, pars planitis has occurred within families; however, as yet, no genetic inheritance pattern has been identified.

Some clinicians have put forward the idea that the immunological response may be the result of one of two possible causes: (1) an isolated set of events internal to the patient (endogenous), or (2) an association with some other disorder (exogenous). Among the disorders with which pars planitis has been associated are: multiple sclerosis, Lyme disease, Behcet disease, sarcoidosis, and tuberculosis, among others.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Affected populations

Pars planitis is an uncommon ocular disorder of children and young adults that affects males slightly more frequently than females.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Diagnosis

Pars planitis is usually diagnosed by means of a thorough physical evaluation, detailed patient history, and specialized eye examination.

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Standard Therapies

Treatment

If no external causes of Pars planitis are found, treatment typically consists of corticosteroid drugs to control inflammation. If steroids are used, the patient must be carefully monitored.

If an external association of pars planitis is identified, then treatment of the associated disorder may take care of the inflammation.

Pars planitis may be accompanied by blood leaking from ruptured small blood vessels in the eye. These are generally not serious and, if necessary, can be treated by laser or cryotherapy (freezing of tissue) to seal blood vessels and arrest leakage.

Other treatments are symptomatic and supportive, as well as treatment of the complications (cataracts, glaucoma, cystoid macular edema, etc).

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

Clinical Trials and Studies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

Also website: www.uveitis.org has information regarding this condition and current trials available.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:

www.centerwatch.com

  • < Previous section
  • Next section >
  • < Previous section
  • Next section >

References

TEXTBOOKS

Guest S. Pars Planitis. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:656-57.

Beers MH, Berkow R, eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:726.

Kanski JJ, ed. Clinical Ophthalmology. 4th ed. Butterworth-Heinemann. Oxford, UK; 1999:309-11.

Newell FW, ed. Ophthalmology: Principles and Concepts. 7th ed. Mosby Year Book, St. Louis, MO; 1991:333-34.

JOURNAL ARTICLES

Abu El-Asrar A, Geboes K. An immunohistochemical study of the ‘snowbank’ in a case of pars planitis. Ocul Immunol Inflamm. 2002;10:117-23.

Greiner KH, Kilmartin DJ, Forrester JV, et al. Grading of pars planitis by ultrasound biomicroscopy/echographic and clinical study. Eur J Ultrasound.2002;15:139-44.

Miserocchi E, Baltatzis S, Ekong A, et al. Efficacy and safety of chlorambucil in intractable noninfectious uveitis: the Massachusetts Eye and Ear Infirmary experience. Ophthalmology. 2002;109:137-42.

Lauer AK, Smith JR, Robertson JE, et al. Vitreous hemorrhage is a common complication of pediatric pars planitis. Ophthalmology. 2002;109:95-98.

Prieto JF, Dios E, Gutierrez JM, et al. Pars planitis: epidemiology, treatment, and association with multiple sclerosis. Ocul Immunol Inflamm. 2001;9:93-102.

Guest S, Funkhouser E, Lightman S. Pars planitis: a comparison of childhood onset and adult onset disease. Clin Experiment Ophthalmol. 2001;29:81-84.

Biousse V, Trichet C, Bloch-Michel E, et al. Multiple sclerosis associated with uveitis in two large clinic-based series. Neurology. 1999;52:179-81.

FROM THE INTERNET

McKusick VA, ed. Online Mendelian Inheritance in Man (OMIM). The Johns Hopkins University. Pars Planitis. Entry Number; 606177: Last Edit Date; 8/8/2001.

Douglas RS. Uveitis. Medical Encylopedia. MEDLINEplus. Update: 12/22/2002. 3pp.

www.nlm.nih.gov/medlineplus/print/ency/article/001005.htm

Pars Planitis: A Syndrome of Unknown Etiology or a Clinical Picture of Multiple Etiologies.

Massachusetts Eye and Ear Infirmary, Immunology Service, 1999. 1p.

www.uveitis.org/enhanced/Backup/webeyemd_htmbank/pars.htm

Ocular Immunology. MEEI. Last Update: 04/08/2003. 3pp.

www.uveitis.org/enhanced/index.htm

pars planitis. General Practice Notebook. © 2003. 1p.

www.gpnotebook.co.uk/simplepage.cfm?ID=772145184

Pars Planitis. Handbook of Ocular Disease management. nd. 2pp.

www.revoptom.com/handbook/SECT35b.HTM

  • < Previous section
  • Next section >

Programs & Resources

RareCare® Assistance Programs

NORD strives to open new assistance programs as funding allows. If we don’t have a program for you now, please continue to check back with us.

Additional Assistance Programs

MedicAlert Assistance Program

NORD and MedicAlert Foundation have teamed up on a new program to provide protection to rare disease patients in emergency situations.

Learn more https://rarediseases.org/patient-assistance-programs/medicalert-assistance-program/

Rare Disease Educational Support Program

Ensuring that patients and caregivers are armed with the tools they need to live their best lives while managing their rare condition is a vital part of NORD’s mission.

Learn more https://rarediseases.org/patient-assistance-programs/rare-disease-educational-support/

Rare Caregiver Respite Program

This first-of-its-kind assistance program is designed for caregivers of a child or adult diagnosed with a rare disorder.

Learn more https://rarediseases.org/patient-assistance-programs/caregiver-respite/

Patient Organizations


National Organization for Rare Disorders