Inclusion Criteria:  Indicated for vitrectomy Natural Lens in place at time of vitrectomy Some cataract present as assessed pre-operatively  Exclusion Criteria:  Previous intraocular surgery in study eye Clear zonular weakness or defects / coloboma Not on stable dose of medications for other conditions. Need for oral corticosteroids during study participation. Evidence or history of diabetic retinopathy, glaucoma, uveitis, or ocular ischemia. Current smoker Use of supplemental oxygen Diabetes Current lung disease (PU, COPD, Asthma) resulting in decreased oxygen saturation. Sensitivity to thiol compounds. Participation in another clinical trial.