An Overview of Pars Planitis

Pars planitis is an eye disease in which the middle layer of the eye, called the uvea, becomes inflamed. The uvea houses three structures of the eye, including the iris—which you’re probably most familiar with—the ciliary body, and the choroid. The uvea also houses the blood supply for the retina.

The pars plana, the region of the eye for which the disease is named, is part of the ciliary body, and the ciliary body is located between the iris and the choroid. If the pars plana becomes inflamed, you may experience symptoms like blurry vision, floaters in the visual field, and eventually, vision loss. Pars planitis usually affects both eyes but can be highly asymmetric. In many cases, the disease is treatable.

Pars planitis may be known by other names as well, including:

• Intermediate uveitis (IU)
• Peripheral retinal inflammation
• Vitritis

Young men are just slightly more at risk of developing pars planitis than women, according to the Genetic and Rare Diseases Center of the National Institutes of Health. To date, the cause of most cases is considered idiopathic, or unknown, but it may be linked to other autoimmune diseases such as multiple sclerosis (MS) or sarcoidosis. Some cases of pars planitis can be associated with some infectious diseases, so it is important that those conditions are ruled out.

Symptoms

The symptoms of par planitis can range from mild in the beginning stages of the disease to more severe as it advances. The symptoms include:

• Blurred vision
• Dark floaters in the visual field that may interfere with sight
• Swelling inside the eye
• Vision loss
• Glaucoma
• Cataracts (as the disease progresses)
• Retinal detachment (as the disease progresses)

Causes

Often, the cause of pars planitis is unknown. However, the National Organization for Rare Diseases notes that the disease may be an autoimmune condition in which the inflammation in the eye is a result of an autoimmune reaction.

In autoimmune disorders, the body’s immune system begins to attack the healthy tissues of the body instead of foreign invaders and pathogens. You may be more likely to develop pars planitis if you have an existing autoimmune disorder.  

In some instances of pars planitis, more than one family member has experienced the eye disease, suggesting there may be a genetic component to the illness. To date, however, researchers haven’t identified a specific gene or the way in which it could be inherited.

Other potential causes include large-scale, bacterial infections like tuberculosis (TB), syphilis, or Lyme disease. 

Diagnosis

To diagnose pars planitis, you’ll likely see an ophthalmologist, a healthcare provider who has expertise in the anatomy, physiology, diseases, and treatments of the eye. The ophthalmologist will take a detailed medical history and perform a specialized eye exam.

During the eye exam, the ophthalmologist will look for signs of inflammation in the eye. When pars planitis is present, there will usually be visible white blood cells grouped together inside the pars plana region of the eyeball—a characteristic feature of pars planitis known as “snowbanks” or “snowballs.” The presence of snowbanks is indicative of eye disease.

In some cases, your healthcare provider may have concerns that your eye condition could be linked to other, undiagnosed illnesses. Your practitioner may order additional tests to rule out the presence of overlapping diseases. These tests may include blood tests to check for infections, an X-ray of the chest, the purified protein derivative skin test used to diagnose TB, or brain magnetic resonance imaging (MRI). 

Treatments

The first step to treating par planitis is to rule out external causes, including infectious and non-infectious possibilities for the disease. Next, your healthcare provider may begin treatment with a local corticosteroid, which can be administered via eye drops or a steroid injection to the eye area.

Your practitioner may also start you on an oral anti-inflammatory; these could be an over-the-counter, nonsteroidal anti-inflammatory medication like naproxen or prescription steroid drugs like prednisone.

If localized and oral treatments don’t produce the desired response, stronger immunosuppressive drugs, such as methotrexate and azathioprine, may be helpful.

Your medical professional may consider surgical interventions if medications aren’t successful. These include cryotherapy to reduce inflammation and pars plana vitrectomy to treat problems with the retina remove gel-like fluid from the eye.

Additionally, your practitioner may recommend other treatments to manage symptoms or complications associated with the disease.  

Prognosis

The sooner you obtain a diagnosis of pars planitis and begin treatment, the better your chances of preventing permanent damage and making a full recovery.  

A Word From Verywell

Getting diagnosed with a medical condition like pars planitis can feel overwhelming, but the sooner you seek treatment, the better your chances of having a good outcome. You may have some questions along the way, so make sure you have a practitioner in your corner you can trust and communicate with. If you continue to notice visual disturbances, don’t ignore them. Be sure to talk to your healthcare provider about your symptoms so that you can stay informed about your treatment options.