<prompt> Which one of the procedure involves using glaucoma drainage deviceViscocanalostomyTrabeculectomyDeep sclerectomySeton operation  <response>: Glaucoma Drainage Devices :- Plastic devices which allow aqeous outflow by creating an alternative communication between the anterior chamber the Sub Tenons space. SETON OPERATION: surgery using glaucoma valve Implants:- Molteno implants , Krupin Denver and Ahmed valve Indications: - Neovacular glaucoma Glaucoma with aniridia Intractable glaucomas where trabeculectomy with anti- metabolite therapy fails. Ref:- A K Khurana Comprehensive Ophthalmology 7th edition; pg num:- 263 