<s>[INST] context: Refractory glaucoma (refractory glaucoma), the drug is difficult to control intraocular pressure, and poor prognosis for conventional surgery glaucoma, the past filtration surgery failed glaucoma, juvenile glaucoma, aphakic eye glaucoma, there are more long-term glaucoma medication history, neovascular glaucoma, secondary glaucoma. Symptoms of Refractory Glaucoma The treatment of refractory glaucoma: multiple surgeries fail the means that may belong to the super healing reaction; teenagers the more hyperophy Tenon and active wound healing response; no lens ocular vitreous can release a trauma fibroblasts stimulating hormone to promote scarring; neovascular glaucoma surgery Road often neovascularization and vascular connective tissue growth, blocking it; yet fully calm inflammation secondary glaucoma, uveitis refractory glaucoma surgery organization strong reaction to the destruction of blood - aqueous barrier, fibronectin and growth factor release, can activate fibroblast proliferation, scarring of the filtration channel. [/INST] question: Drug used in refractory glaucoma - | options: A: Systemic glucocoicoid B: ACE inhibitor C: Alpha agonist D: Beta blocker | answer: C </s>