The Paul Tube Glaucoma Implant (AOI) is a glaucoma drainage device designed by Professor Paul Chew from Singapore. It has a number of advantages over existing devices with a smaller bore tube of 127 microns that can be stented with a 6/0 Prolene, without the need for a Vicryl tie or Sherwood slits.  The silicone plate is 342.1 mm2, more pliable and lower profile than the Baerveldt shunt. Controlled flow can be more reliably achieved earlier in the immediate post-operative period and reduce IOP fluctuations.