Glaucoma
Glaucoma is currently one of the world's leading causes of irreversible blindness.
Read article ↗WHAT YOU NEED TO KNOW
- In some cases of glaucoma, a new outflow route must be created for aqueous humour, the fluid circulating inside the eye.
- In my practice, I use the PRESERFLO MicroShunt and the Ahmed FP7, PAUL and Ahmed ClearPath posterior drainage devices.
- Choose one of the four implants and press Play.
In some cases of glaucoma, a new outflow route must be created for aqueous humour, the fluid circulating inside the eye. Drainage implants help lower intraocular pressure by directing this fluid to the tissues beneath the conjunctiva, where it is absorbed.
In my practice, I use the PRESERFLO MicroShunt and the posterior drainage devices Ahmed FP7, PAUL and Ahmed ClearPath. The choice depends on the eye's characteristics and each person's treatment plan.
See how it works
Choose one of the four implants and press Play. You can pause the animation or explore each step at your own pace.
PRESERFLO MicroShunt
It is a microtube connecting the anterior chamber to the space beneath the conjunctiva. It does not have the plate used in posterior drainage devices. Drainage takes place into a filtration area beneath the tissues covering the eye's surface.
Posterior drainage devices
The Ahmed FP7, PAUL and ClearPath use a tube connected to a plate. The plate sits on the eye's outer surface, further back and covered by conjunctiva; the tube connects it to the inside of the eye. “Posterior” refers to the position of the plate and does not mean fluid is directed towards the retina.
- Ahmed FP7 — New World Medical: includes a valve that helps regulate drainage.
- PAUL — Advanced Ophthalmic Innovations: a non-valved device with a small-calibre tube.
- Ahmed ClearPath — New World Medical: a non-valved tube-and-plate device.
Initial drainage may require flow-control measures adapted to the device and eye. The animation illustrates the fluid's path, not every technical step of the operation.
The aim of treatment
The aim is to control intraocular pressure and help preserve existing vision. Surgery does not restore vision already lost to glaucoma. Postoperative follow-up is essential, and medication or treatment adjustments may still be necessary.
PATIENT GUIDE
After glaucoma surgery
Protection, medication and follow-up after trabeculectomy, deep sclerectomy or drainage implants.
This information does not replace an individual medical assessment. Follow the advice of the team looking after you.
Before deciding, discuss these points at your appointment
- Indication
- What is the purpose of the procedure in my case?
- Alternatives
- What other options may be appropriate for my eyes?
- Recovery
- What care and follow-up will I need?
- Benefits and limitations
- What result can I expect, and what risks should I consider?
Dr. Nuno Lopes · Patient information
Editorial presentation updated on 27 October 2026. Your team's individual instructions take priority.
