Glaucoma stent surgery, a type of Minimally Invasive Glaucoma Surgery (MIGS), is designed to manage glaucoma by lowering intraocular pressure (IOP). These procedures involve implanting a microscopic device to improve the drainage of the eye’s natural fluid, the aqueous humor. The primary goal is to stabilize vision and reduce a patient’s dependence on daily glaucoma medications. While considered safer than traditional glaucoma operations, MIGS procedures are still surgery and come with potential side effects and risks.
Immediate and Common Post-Surgical Effects
In the first few days following surgery, it is common to experience temporary effects as the eye heals. Many patients report blurry or hazy vision, which generally improves as the eye stabilizes. A foreign body sensation, general redness, and minor eyelid swelling are also frequently reported. These symptoms are a typical response to the procedure, are managed with prescribed anti-inflammatory eye drops, and resolve on their own.
Potential Surgical Complications
One potential issue is a temporary spike in intraocular pressure shortly after the procedure. This can happen if the eye’s drainage system becomes temporarily inflamed or blocked by residual material used during surgery. Surgeons mitigate this risk by thoroughly cleaning the area before concluding the procedure.
Conversely, the eye pressure can drop too low, a condition called hypotony. This happens if the new drainage channel allows too much fluid to exit the eye too quickly. While often temporary, persistent hypotony can lead to fluid collecting behind the retina or other issues that might affect vision and could require intervention.
Bleeding into the front chamber of the eye, a complication known as hyphema, can also occur. This is more common if delicate blood vessels are disturbed during the stent’s placement. While minor bleeding often resolves on its own, a significant hyphema can obstruct the new drainage path or cause a pressure spike, sometimes requiring a second procedure to clear the blood.
Beyond surface irritation, a more serious internal inflammation like iritis or uveitis is also a risk. This occurs when the iris or other internal structures of the eye become inflamed as a reaction to the surgery. Such inflammation requires treatment with steroid eye drops to prevent long-term damage, such as scarring within the eye’s drainage structures.
Stent-Specific Issues
Over time, a stent can become blocked or occluded. The stent’s opening may be obstructed by blood cells, inflammatory debris, or tissue that has moved against the implant. This blockage prevents the stent from draining fluid effectively, which can cause intraocular pressure to rise again.
The stent may also move from its original position, which is referred to as stent malposition or migration. An incorrectly positioned stent will not function properly and could pose a risk to other structures within the eye, such as the cornea. A surgeon may need to perform a procedure to reposition or, in some cases, remove it.
Long-Term Risks and Considerations
A significant long-term consideration is the health of the cornea. Some stent placements can put the device too close to the corneal endothelium, a layer of cells responsible for keeping the cornea clear. Long-term contact can lead to a gradual loss of these cells, which do not regenerate, potentially causing corneal clouding.
The surgery itself can accelerate the formation or progression of a cataract, the natural clouding of the eye’s lens. While this is a common age-related change, intraocular surgery can speed up the process. For this reason, many MIGS procedures are performed at the same time as cataract surgery.
A glaucoma stent may not be a permanent solution. Over several years, the body’s healing processes can cause scar tissue to form around the stent, reducing its effectiveness. In such cases, a patient’s intraocular pressure may rise again, necessitating a return to glaucoma medications or another surgical procedure.
When to Contact Your Doctor
You should attend all scheduled follow-up appointments, but contact your ophthalmologist immediately if certain symptoms arise. Prompt attention is required for signs of a serious complication.
Contact your doctor if you experience any of the following:
- Severe or worsening eye pain, different from mild post-surgical discomfort
- A sudden decrease in vision beyond the initial expected blurriness
- New floaters (spots or webs) or flashes of light in your vision
- Pus-like or thick discharge from the eye
- A significant increase in redness or swelling, especially if accompanied by pain or fever