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Glaucoma Tube Implant Surgery

Illustration of an eye with glaucoma tube implant

Glaucoma tube implant surgery involves inserting a device into the eye which lowers the eye pressure by draining fluid out.

Types of Glaucoma Tube Implants


There are a few types of Glaucoma tube implants, all of which have a small tube as well as a larger plate attached. The two main types of tubes used worldwide are the Ahmed and Baerveldt tubes. Studies have shown that the Baerveldt tube is more effective in lowering the eye pressure compared with the Ahmed tube, likely because it has a larger plate than the Ahmed. However, there are more complications associated with the Baerveldt tube, including a higher risk of low eye pressure which can result in vision loss. 

In recent years, we have a new tube called the Paul Glaucoma Implant, or PGI for short. It has a smaller inner tube size of 0.1mm compared with 0.3mm for the Ahmed and Baerveldt tubes. The plate size of the PGI is larger than the Ahmed and more similar to the Baerveldt tube. Hence, early studies suggest that the efficacy of the PGI may be similar to the Baerveldt and better than the Ahmed, with a low rate of complications including low eye pressure.

Paul Glaucoma Implant

Glaucoma Tube Implant Surgery Procedure

Your eye surgeon makes an incision in the conjunctiva, the outermost layer covering the white part of the eye. This allows the tube implant to be inserted underneath the conjunctiva. The plate is stitched to the sclera, the white outer wall of the eye. The tube is then inserted into the eye, stitched to the sclera and covered with a patch as well as with conjunctiva. After tube implant surgery, fluid flows out of the eye through the tube and spreads over the plate.

Points to note about the procedure: 

  • Those on blood thinners need to stop them before surgery.
  • It is a day procedure performed under general anesthesia.
  • You will be prescribed antibiotics and steroid eye drops to prevent infection and scarring. 
  • Do not swim for 3-4 weeks after the surgery. 
  • Avoid exertion for 3-4 weeks after the surgery. 
  • Cover the eye with a shield when you sleep for a few weeks after the surgery. 

Complications of Tube Implant Surgery

Tube implant surgery is an effective glaucoma surgery for lowering the eye pressure, but as with any procedure, there are potential complications. It is important to discuss these with your eye surgeon in detail.

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    Dr Chelvin Sng of Chelvin Sng eye center

    Dr Chelvin Sng

    Adjunct Associate Professor
    Senior Consultant Ophthalmologist
    ✓ 4 Gold Medals (Specialist Accreditation Examination)
    ✓ "Top 50 Rising Stars” (2017), “Top 100 Female Ophthalmologists” (2021), "Top 100 Ophthalmologists" (2022) "Top 100 Ophthalmologists" (2023) and "Top 100 Ophthalmologists" (2024)
    ⋆ Global Ophthalmologist Power List (voted by peers worldwide)
    ✓ Cambridge University Graduate with Triple First Class Honours and Distinctions


    38 Irrawaddy Road Mt Elizabeth Novena Specialist Centre, #06-25, Singapore 329563

    Operating Hours

    Mon - Fri: 9am - 5pm
    Saturday: 9am - 1pm
    Sunday / PH: Closed