What Are Traditional Glaucoma Surgeries?
Trabeculectomy and tube shunt surgery are considered traditional “filtering” procedures that aim to create new drainage pathways for fluid within the eye to reduce intraocular pressure and help manage glaucoma. Both are outpatient surgeries, like cataract surgery. Trabeculectomy involves making a flap in the sclera, the white part of the eye, and creating a pathway underneath it to allow fluid to drain more effectively. The flap is then repositioned and covered with the conjunctiva, the outer layer of the eye. A tube shunt surgery similarly filters fluid from the inside of the eye to the outside of the eye, however it involves implanting a small tube shunt instead of creating a flap using ocular tissue.
How They Work
Trabeculectomy surgery creates a small fluid-filled blister, called a bleb, located on the eye's surface beneath the eyelid. This bleb helps absorb excess fluid into the blood vessels without causing noticeable tearing. Since it is hidden by the upper eyelid, the bleb is generally not visible to others. For a tube shunt, the small flexible tube portion is inserted into the eye and connects to an external plate which is sutured to the sclera, and covered with conjunctiva. The portion of the tube that exits the eye is also covered with a patch graft to prevent exposure. The conjunctiva is typically carefully closed with tiny sutures which dissolve as the healing process is completed.
While neither surgery restores lost vision due to glaucoma, the primary goal is to prevent further vision loss by lowering eye pressure.
Why Might You Need a Trabeculectomy or Tube Shunt Surgery?
Glaucoma is an eye condition in which increased eye pressure damages the optic nerve, potentially leading to vision loss and, if untreated, blindness. Trabeculectomy or tube shunt surgery may be recommended to prevent the progression of glaucoma in cases where other treatments, such as eye drops or laser therapy, have been insufficient or are not suitable. This procedure is applicable for both closed-angle and open-angle glaucoma, as well as primary and secondary types.
Risks of Trabeculectomy and Tube Shunt Surgery
Though generally effective, trabeculectomy and tube shunt surgery carry risks, which include but are not limited to:
- Failure to Control Eye Pressure: This can occur due to scarring that obstructs fluid drainage. In such cases, additional surgery or scar tissue removal might be needed.
- Fluid Leakage: Sometimes the fluid leakage resolves on its own, but it may require further surgery if it persists.
- Low Eye Pressure: Excessive fluid drainage can lead to too-low eye pressure, which may require further surgical adjustments.
- Bleeding: Rarely, bleeding inside the eye may occur, potentially impacting vision.
- Infections: Post-surgical infections could affect vision if not treated promptly.
- Cataracts: Trabeculectomy and tube shunt surgery may accelerate cataract formation, which can be addressed with subsequent cataract surgery.
Individual risks vary based on age, health, and eye anatomy. Discuss these with your eye care provider to understand what applies to you.
Preparing for Trabeculectomy or Tube Shunt Surgery
Consult your eye doctor about how to prepare for your procedure. You may need to stop taking certain medications, especially blood thinners, before surgery. Avoid eating or drinking after midnight before the day of your surgery, and you might need to refrain from strenuous activities post-surgery.
What to Expect During the Procedure
Trabeculectomy and tube shunt surgery typically involve:
- Being awake during the procedure with relaxation medication and local anesthesia. In some cases, general anesthesia might be used.
- Application of anti-fibrotic medication during and after the surgery to minimize scarring (for trabeculectomy).
- Rotation and temporary fixation of the eye by your surgeon.
- Placement of antibiotics and a post-surgical patch over your eye, which you’ll typically keep on until your follow-up appointment.
After the Procedure
Most patients can go home the same day. Arrange for a driver as you will likely be unable to drive yourself. You may experience some discomfort, which can usually be managed with over-the-counter pain relievers.
Post-surgery care includes:
- Using steroid eye drops to aid healing and prevent scarring.
- Wearing an eye shield while sleeping to avoid accidental pressure.
- Avoiding eye rubbing and heavy lifting or strenuous activities.
- Monitoring for serious symptoms like bleeding, fever, worsening vision, or severe swelling and contacting your doctor if they occur.
Other Surgical Options
Trabeculectomy and tube shunt surgery are just two of several surgical treatments for glaucoma. Other options include:
- Internal stents to open drainage pathways within the eye.
- Tissue removal from the eye’s drainage system.
- Laser procedures to slow fluid production within the eye.
Discuss all available options with your care team to determine the best approach for your condition.