Vitrectomy for the diagnosis and management of uveitis of unknown cause.

Purpose: To determine the diagnostic yield of tests commonly used for vitreous fluid analysis in eyes with suspected intraocular infection or malignancy.
Design: Noncomparative interventional case series.
Participants: Forty-four consecutive patients (45 eyes) treated from 1998 through 2006 with posterior segment inflammation who underwent pars plana vitrectomy for diagnostic purposes.
Intervention: Vitreous specimens obtained via pars plana vitrectomy were analyzed by microbiologic culture, cytologic analysis, and flow cytometry.
Main Outcome Measures: Diagnostic yield and sensitivity of each test performed on vitreous specimens and visual outcomes of eyes that underwent diagnostic vitrectomy (DVx).
Results: Preoperative diagnoses were infection in 15 eyes and malignancy in 30 eyes. Overall, vitreous analysis identified a specific cause in 9 (20%) of 45 eyes. The overall sensitivity of DVx was 63.6%. The sensitivities of individual tests were: culture, 50%; cytologic analysis, 66.7%; and flow cytometry, 83.3%. The yields of diagnostic tests were: culture, 5.7%; cytologic analysis, 14.3%; and flow cytometry, 20.6%. Final diagnoses were infection in 6 eyes, malignancy in 9 eyes, and idiopathic in 30 eyes. Mean visual acuity improved significantly in the first 6 months after DVx. Visual acuity improved in 60% of eyes, with 37.8% of eyes improving by 3 lines or more.
Conclusions: Analysis of vitreous fluid by widely available tests is useful in identifying intraocular infection or malignancy. Most patients experienced a substantial improvement in vision.