Analysis of Aqueous and Vitreous Humor

Inclusion Criteria: * Ability to provide written informed consent and comply with study assessments for the full duration of the study * Age \> 18 years * Subjects with a diagnosis of tractional retinal detachment secondary to proliferative diabetic retinopathy, age-related macular degeneration with tractional or exudative retinal detachment, macular hole, epiretinal membrane, or neovascular glaucoma. Exclusion Criteria: * Subjects with history of vitrectomy in the study eye * Presence of vitreous hemorrhage * Subjects with history of laser photocoagulation in the study eye within 3 months of vitrectomy * Subjects unwilling to undergo pars plana vitrectomy * Subjects unwilling to receive intravitreal ranibizumab prior to pars plana vitrectomy unless diagnosis of macular hole or epiretinal membrane * Subjects who may need or have received systemic anti-VEGF for oncology in the past year * Subjects with history of anti-VEGF injection within 4 months before vitrectomy