Figure 5.

Proposed mechanism for development of post-vitrectomy glaucoma. Upper left image: Low levels of pO₂ in vitreous cavity, surrounding clear lens and in anterior chamber (AC) angle. Oxygen diffuses across cornea into the AC and from retinal blood vessels into the vitreous cavity. Center left image: Following pars plana vitrectomy surgery, pO₂ increases in the vitreous cavity, around lens, in AC angle and posterior chamber with development of nuclear sclerotic cataract. Lower left image: Following cataract extraction and intraocular lens implantation (IOL), pO₂ increases in the AC angle, posterior chamber and mid-AC. Upper right image: Expanded view of AC angle illustrating alterations in aqueous humor including increased pO₂ surrounding lens implant and in AC angle leading to increased reactive oxygen species formation (brown; ROS) and decreased antioxidants (green). Lower right image: Proposed cascade of events following vitrectomy and IOL implantation ultimately leading to increased intraocular pressure (IOP) and risk of glaucoma.

O₂⁻ = superoxide anion, H₂O₂ = hydrogen peroxide, OH⁻ = hydroxyl ion, O₂⁻² = peroxide, TRAP = total reactive antioxidant potential, AsA = ascorbate, SOD= superoxide dismutase, GSH= glutathione, TM = trabecular meshwork