The pars plana is the middle layer of the eye located in between the retina and the iris. As part of the ciliary body, it has a role in the formation of the vitreous fluid that fills the anterior portion of the eyeball. The other part of the ciliary body is pars plicata. It is the optimum incision point for ophthalmological procedures to avoid damage to the retina and the lens of the eye.
Disorders of the pars plana have various causes. An injury to the eyeball can cause damage to the delicate tissue that comprises the pars plana. Bacterial or viral infections can cause inflammation, and proliferative diabetic retinopathy may cause changes in the eye. Retinal detachment may injure the pars plana when the retina moves from its natural location.
A condition called pars planitis occurs when its layers becomes inflamed after or during an infection. Materials that develops during an infection, called exudates, combine with white blood cells to fill the middle layer of the eye. The foreign material can be visible as obstructions in the patient’s visual field.
Treatment for pars planitis involves clearing the cloudy vitreous fluid in the eyeball. For some patients, the cloudy fluid will eventually clear without further treatment. Other people may need a surgical procedure to remove the cloudy fluid that has built up. Vision loss from pars planitis is noticed among 20% of people diagnosed with this condition.
Immunosuppressant medications and steroids are used to relieve the inflammation that causes the exudates to form in pars planitis. Most ophthalmologists will recommend a series of six injections of a steroid medicine, given directly into the pars plana. These injection treatments prevent the inflammation from occurring. If the inflammation does not return after the injection series is completed, the condition is considered in remission.
The return of inflammation in the pars plana following treatment with the steroid may signal a need to begin immunosuppressive therapy. By lowering the immune response with medication, the ability of the body to produce inflammatory materials is reduced. Treatment with immune suppressing drugs is generally very effective for the long-term management of the inflamed pars plana.
Surgical removal of the affected vitreous fluid is only done after the first two methods of treatment have failed to relieve the buildup of exudates in the eye. A vitrectomy is the procedure to remove vitreous fluid. The surgeon will make three incisions into the eyeball, remove the clouded fluid, and replace the same amount. Recovery time from a vitrectomy is different for each person that undergoes the procedure.