• Intermediate uveitis (IU) is inflammation primarily, of the anterior vitreous, ciliary body, and peripheral retina.
• Pars planitis is a subset of IU for which there is no associated infection or systemic disease.
• IU comprises ∼15% of all cases of uveitis
• No gender predisposition
• Bilateral in 70–90% of cases, but can be asymmetric
• Pars planitis accounts for 85–90% of intermediate uveitis
– It has a bimodal distribution; the younger age group is 5–15 years, and older age group is 20–40 years
Pars planitis has been shown to be associated with HLA-DR15 and HLA-DR51
• The pathophysiology of IU/pars planitis is not well understood
– It is probably an autoimmune reaction against an ocular antigen
• Peripheral retinal veins are the primary foci for inflammation
COMMONLY ASSOCIATED CONDITIONS
• Multiple sclerosis
• Infectious conditions
– Lyme’s disease
• Pars planitis has no associated systemic condition
• Patients present with floaters and decreased vision
• Usually a white, quiet eye, but patients can experience redness and photophobia (more commonly in children).
• Anterior vitreous cellular reaction
• Snowballs, which are aggregates of vitreous cells
• Snowbanks, which are inflammatory pars plana exudates, typically found inferiorly
– Tends to indicate more severe disease
• Vascular tortuosity and peripheral retinal phlebitis
In children, IU tends to cause greater anterior chamber inflammation
DIAGNOSTIC TESTS & INTERPRETATION
• Complete blood count (CBC) with differential count
• Erythrocyte sedimentation rate (ESR)
• Purified protein derivative (PPD) skin test
• Angiotensin-converting enzyme (ACE) level, which can be elevated in sarcoidosis
• Consider serologic testing for Lyme’s, syphilis, and Bartonella
• Chest X-ray to assess for sarcoidosis and tuberculosis
– If chest X-ray is negative, consider gallium scan or computed tomography (CT) to rule out sarcoidosis if clinical suspicion is high
• Fluorescein angiography is helpful in determining presence of cystoid macular edema (CME), retinal phlebitis, and neovascularization.
• Ultrasound biomicroscopy (UBM) can demonstrate pars plana exudates and vitreitis in cases with small pupil
• Diagnostic vitrectomy may be needed in cases where there is suspicion of intraocular lymphoma, endophthalmitis, or in cases refractory to medical therapy
• Histologic findings show lymphocytic infiltration of retinal veins
• Pars plana exudates consist of fibroglial tissue with inflammatory cells
• Primary central nervous system lymphoma
• Other uveitic conditions, including Vogt–Koyanagi–Harada disease and Fuch’s heterochromic cyclitis
• Treat underlying cause of disease if infectious etiology is present
• For other cases, corticosteroids are indicated if patient is symptomatic or has vision loss.
– Periocular corticosteroids are first line
– Oral corticosteroids is indicated if local therapy is ineffective, or if there is bilateral severe disease
– Intravitreal injection for refractory cases
• Immunomodulatory therapy if corticosteroids fail or side effects cannot be tolerated
– Mycophenolate mofetil
• If drug therapy fails, cryotherapy and laser photocoagulation can be performed to peripheral retina for ablation of pars plana exudates and neovascularization
• Pars plana vitrectomy (PPV) for chronic inflammation or structural complications such as retinal detachment
– PPV is helpful in reducing CME
• Rheumatology or infectious disease specialist, depending on etiology
• IU generally has a chronic course with exacerbations and remissions, although a small subset of patients have self-limiting disease
– Of all subsets of uveitis, IU tends to have the longest duration, most cases last for 5–15 years but can be longer
• Visual outcome is related to severity of disease and presence of CME
– Pars plana exudate indicates poorer prognosis
• Pars planitis has an overall favorable visual prognosis
• Chronic inflammation from IU can lead to CME.
• Cataracts result from both chronic inflammation and corticosteroid therapy
– Perioperative use of corticosteroids is needed to control inflammation.
• Glaucoma, both angle closure and open angle
• Band keratopathy
• Peripheral retinal neovascularization
• Vitreous hemorrhage
• Retinal detachment
• Bloch-Michel E, Nussenblatt RB. International Uveitis Study Group recommendations for the evaluation of intraocular inflammatory disease. Am J Ophthalmol 1987;103:234–235.
• Jabs DA, Nusenblatt RB, Rosenbaum JT. Standardization of Uveitis nomenclature (SUN) working group. Standardization of uveitis nomenclature for reporting clinical data. Results of the First International Workshop. Am J Ophthalmol 2005;140:509–516.
• 363.21 Pars planitis
• 364.3 Unspecified iridocyclitis