Ahmed Valve (Glaucoma Tube) Technique
Title: Ahmed Valve (Glaucoma Tube) Technique
Author: Austin Nakatsuka, MD and Norman Zabriskie, MD
Date: 8/22/2022
Keywords/Main Subjects: Glaucoma Tube Shunt; Valve
Description:
Indication: Moderate to Severe Glaucoma
Key Materials/Instruments:
Ahmed Valve FP-7
7-0 vicryl suture
5-0 prolene suture
10-0 vicryl suture
23 gauge needle
Dispersive Viscoelastic
Anesthesia:
Retrobulbar block
Surgical Steps:
A 7-0 vicryl traction suture is placed along with a corneal light shield.
A conjunctival peritomy is performed in the superotemporal quadrant, with incisions at the limbus and relaxing incisions superiorly and temporally. A blunt wescotts scissors is used for the initial dissection and a Stevens tenotomy scissors is used to create space posteriorly in the superotemporal quadrant. The superior and lateral rectus muscles are identified and marked. The sclera is marked 7-8 mm from the limbus where the plate will rest. The Ahmed valve is then prepared and primed with BSS which is injected through the tube with a 27 gauge cannula. A burst of BSS posteriorly from the plate indicates that the valve is open. The plate is then tucked into the superotemporal quadrant and fixed to the sclera with 9-0 nylon suture. The tube is then trimmed to a size that would be appropriate for the anterior chamber. A bevel is made anteriorly so that iris will not be incarcerated in the tube. A 5-0 prolene suture is placed through the tube lumen, stopping just short of the valve mechanism. A piece of 7-0 vicryl suture from the original traction suture is used to tie a tight partially ligating suture around the tube lumen and the prolene suture. The prolene is then removed. A 23 gauge needle is used to enter the anterior chamber. The tube is inserted into the anterior chamber using two tying forceps. A paracentesis incision is made and dispersive viscoelastic is injected to fill the chamber. When the tube is in a good position, a 10-0 vicryl suture is used to secure the tube along the desired pathway in an “X” pattern. A tutoplast graft of cornea or sclera is cut in a square and fastened over the tube entry with 10-0 vicryl suture. The conjunctiva is then mobilized over the plate and graft and the corners are brought up to their original position. The corners are secured with 10-0 vicryl suture tied in a horizontal mattress fashion. Additional horizontal mattress sutures are used to close the relaxing incisions and secure the conjunctiva to the limbus. The tube is checked again to ensure it is in good position in the anterior chamber. The eye is then patched and shielded with ointment, antibiotic drops, and a collagen shield.
Format: video
Identifier: Moran_CORE_125956
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