Gas Tamponade for Prevention of Postoperative Vitreous Hemorrhage in Diabetics

Hypothesis: Patients undergoing pars plana vitrectomy for the indication of diabetic vitreous hemorrhage will have a lower incidence of postoperative vitreous hemorrhaging during the 6-month trial period when vitreous substitution with 20-30% sulfur hexafluoride gas is utilized compared to vitreous substitution with balanced salt solution.

Subjects enrolled into the study are randomized into one of the ensuing treatment cohorts: Group A patients undergo vitreous substitution with 20-30% sulfur hexafluoride (SF6) gas during PPV, whereas Group B patients undergo vitreous substitution with balanced salt solution (BSS) during PPV. Simple randomization allocates patients into treatment groups during PPV. Once all relevant maneuvers are completed by the surgeon prior to vitreous substitution, a simulated coin toss program decides the vitreous substitute, and therefore which group the patient enters. Randomization intraoperatively mitigates against selection bias of utilized surgical maneuvers such as endodiathermy on the part of the surgeon and allows for subjects to not undergo randomization in cases where intraoperative retinal breaks occur that would preclude the subject from receiving vitreous substitution with BSS. Subjects undergo data collection at 3 postoperative visits: 1) 15 +/- 5 days following PPV, 2) 40 +/- 10 days following PPV, and 3) 185 +/- 15 days following PPV. Study subjects are evaluated at non-study times at the judgment of the examiner.