Pars planitis.

The records on thirty-three patients (58 eyes) with the diagnosis of pars planitis were reviewed. The patients were divided into 4 groups: Group 1 had bilateral vitreous cells and pars plana 'snowbank' formation (13 patients, 26 eyes), Group 2 had bilateral vitreous cells and 'snowbank' formation in one eye only (8 patients, 16 eyes), Group 3 had vitreous cells and 'snowbank' formation in one eye only (8 patients, 8 eyes), and Group 4 had bilateral vitreous cells without 'snowbank' formation (4 patients, 8 eyes). Frequent findings and complications were tabulated; cystoid macular oedema was the most common cause of decreased vision. Although pars plana 'snowbank' exudates are usually present in pars planitis, they may not be necessary to make the diagnosis. An approach to therapy is outlined.