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Glaucoma Stent Revision Surgery Guided by Intraoperative OCT

Understand the workflow and how OCT can improve glaucoma surgery decision-making

Dr. Sheybani places the new subconjunctival stent in the anterior chamber. Images courtesy of Arsham Sheybani, MD. Subconjunctival_stent_in_the_anterior_chamber.jpg

Glaucoma is one of the leading causes of irreversible blindness worldwide. Historical surgical techniques such as trabeculectomy and tube-shunt drainage pose significant short term risks and potential complications. Surgical approaches have considerably evolved in recent years, with the emergence of minimally invasive glaucoma surgery (MIGS) offering minimal tissue disruption, ab-interno implantation, short surgical time, simple instrumentation and fast postoperative recovery. 

This includes the use of microstents that can lower intraocular pressure (IOP) via subconjunctival drainage [1]. However, these subconjunctival stents can fail, requiring revision surgery. The use of intraoperative OCT plays an important role in these procedures, allowing to see whether the stent is embedded in the tenons layer.

About the Case Study

Key Learnings:

  • Learn about the surgical management of a 64-year-old female with a prior subconjunctival stent that had failed, with tenons fibrosis
  • Discover the different steps of the revisional glaucoma surgery
  • Understand the role of intraoperative OCT in surgical decision-making

Case Description

A 64-year-old female had a prior subconjunctival stent which had failed, with tenons fibrosis. The contralateral eye had counting fingers vision after hypotony from tube shunt. The failed subconjunctival stent had previously been performed with a conjunctival dissection from an external approach.

The patient declined further intervention including diode CPC when her subconjunctival stent failed. She was only amenable to revision.

Pre-operative assessment 

Pressure was very elevated pre-operatively, with an IOP of 31mmHg in the right eye. To lower the risk of subconjunctival hemorrhage, the patient was started on oral acetazolamide. The surgeon also proceeded to bleb revision within a week after pre-treating with difluprednate. 

The surgical plan was to revise the old subconjunctival stent and place a new one if there was no flow, using the intraoperative OCT on the wound closure to determine if the implant was free of tenons.

Surgical approach

After the peritomy, subconjunctival marking was injected, working with great care around the scar tissue to avoid cutting or damaging the stent in case it could be left in. 

However, there was a wall of tenons around it. With a 27-gauge needle, it was freed from the surrounding tissue. There was not a lot of ischemia from the prior mitomycin treatment associated with these stents, but there was no flow of the device.

Despite backflushing the device, and blowing through any clog in the stent through a firm injection, there still was no flow. As such, the decision was made to remove the stent to avoid two filtration procedures. The stent was removed very carefully given its fragility and brittleness.

Continue Reading

Read more and discover how Dr. Sheybani carried out the revision surgery utilizing intraoperative OCT on the Proveo 8 surgical microscope.

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Disclaimer: Please note that off-label uses of products may be discussed. Consult with regulatory affairs for cleared indications for use in your region. The statements of the healthcare professionals included in this presentation reflect only their opinion and personal experience. They do not necessarily reflect the opinion of any institution with whom they are affiliated or Leica Microsystems.


  1. Xen Glaucoma Treatment System, EyeWiki, American Academy of Ophthalmology (AAO), Accessed on October 19th 2022 at: 
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