Glaucoma is a progressive eye condition characterized by damage to the optic nerve, often associated with elevated intraocular pressure (IOP), or the fluid pressure inside the eye. The primary purpose of medical treatment, laser procedures, or surgery is to lower this eye pressure to prevent further, irreversible vision loss. When medications and less invasive laser treatments are no longer sufficient to control the pressure and halt the disease’s progression, surgical intervention becomes necessary to protect remaining sight.
Decision to Undergo Surgery
The choice to proceed with surgery involves a calculated risk-benefit analysis, weighing potential complications against the near-certainty of vision loss from uncontrolled glaucoma. Surgery is typically recommended when a patient’s target eye pressure cannot be achieved or maintained with maximum tolerated medical therapy. Signs that a patient may need surgery include rapid progression of optic nerve damage or visual field loss despite treatment, or presenting with advanced disease initially.
The decision is highly individualized, considering the patient’s age, overall health, specific type and severity of glaucoma, and the required pressure level to stabilize the condition. For instance, a patient requiring a very low pressure target may be guided toward a more aggressive procedure. The goal of the operation is to prevent future damage and preserve the patient’s current level of sight, not to restore lost vision.
Types of Glaucoma Surgery
Glaucoma surgery is generally divided into categories based on the technique used to improve fluid drainage and lower eye pressure. Filtering surgery, such as a trabeculectomy, is considered the traditional standard and involves creating a new drainage pathway. A small flap is made in the sclera, allowing the internal fluid to filter into a space underneath the conjunctiva to be reabsorbed.
Drainage device surgery, also called tube shunts, is another conventional method often used when trabeculectomy is likely to fail, such as in cases of certain secondary glaucomas. This procedure involves implanting a small tube into the eye’s anterior chamber, which connects to a plate secured on the eye’s surface to shunt fluid away.
Minimally Invasive Glaucoma Surgery (MIGS) procedures use microscopic instruments and tiny incisions to enhance the eye’s natural drainage system. These methods include the use of micro-stents or bypass operations and are favored for mild to moderate cases due to their higher safety profile. While MIGS procedures carry fewer complications, they may not be as effective at achieving very low pressure targets as the more invasive traditional operations.
Specific Surgical Risks and Complications
While glaucoma surgery is often successful, it carries specific risks that can be serious, though they are uncommon. One of the most feared complications is endophthalmitis, a severe infection inside the eye that can occur months or even years after the operation. This condition is rare, occurring in less than 0.1% of cases, but can lead to permanent vision loss if not treated immediately with antibiotic injections.
Another complication is hypotony, where the eye pressure drops too low, which can result in swelling of the optic disc or fluid accumulation behind the retina, potentially causing blurry vision. Conversely, the procedure can fail over time, most often due to scarring that closes the newly created drainage pathway, leading to the pressure rising again. This failure can necessitate the patient resuming eye drops or undergoing additional surgery to revise the drainage.
Bleeding inside the eye, known as hemorrhage, is another risk, which can range from minor to severe, especially a rare suprachoroidal hemorrhage that can threaten vision. Additionally, any intraocular surgery can accelerate the formation of cataracts, which is the clouding of the eye’s natural lens.
Managing Post-Operative Expectations
Immediately following the procedure, patients should anticipate several temporary and common side effects that are part of the normal healing process. Blurred vision is very common and can persist for a few days to several weeks as the eye adjusts to the new pressure and the surgical site heals. This blurriness is not typically a sign of failure but a temporary side effect of recovery.
The operated eye will often appear red, watery, and feel irritated, sometimes described as a gritty sensation. These symptoms are usually managed with prescribed antibiotic and anti-inflammatory eye drops, which must be taken exactly as instructed to prevent infection and control inflammation. Patients are advised to avoid strenuous activities, heavy lifting, and bending over for a period to prevent undue pressure on the surgical site.
Frequent follow-up visits with the surgeon are necessary in the weeks following the operation to monitor the eye pressure and healing. During this time, the surgeon will adjust medications and may perform minor in-office procedures to ensure the drainage is functioning correctly. Understanding that these temporary effects are normal can significantly reduce patient anxiety.