What are the primary surgical approaches for treating angle-based glaucoma?

From the Guidelines

The primary surgical approaches for treating angle-based glaucoma include trabeculectomy, glaucoma drainage devices, minimally invasive glaucoma surgery (MIGS), and laser procedures. These surgeries work by either improving aqueous outflow or reducing its production to lower intraocular pressure, which is the primary modifiable risk factor for glaucoma progression.

Surgical Approaches

• Trabeculectomy creates a new drainage pathway by removing a small portion of the trabecular meshwork and adjacent structures, allowing aqueous humor to flow from the anterior chamber to a subconjunctival bleb.
• Glaucoma drainage devices, such as Ahmed or Baerveldt implants, use a tube to shunt aqueous humor from the anterior chamber to an external reservoir.
• MIGS procedures include trabecular micro-bypass stents (iStent, Hydrus), trabectome, and goniotomy, which enhance the natural outflow pathways with less tissue disruption.
• Laser procedures like selective laser trabeculoplasty (SLT) and endoscopic cyclophotocoagulation (ECP) are less invasive options that improve aqueous outflow or reduce its production. The choice of procedure depends on glaucoma severity, previous treatments, patient factors, and surgeon preference, as noted in studies such as 1 and 1. Most procedures require postoperative management with topical steroids and antibiotics, and patients need regular follow-up to monitor intraocular pressure and potential complications.

Key Considerations

• Lowering intraocular pressure (IOP) is crucial in managing glaucoma, as it slows the progression of the disease and prevents further damage to the optic nerve 1.
• The effectiveness of these surgical approaches can vary depending on the individual patient and the specific type of glaucoma being treated, with some studies suggesting that trabeculectomy may be more effective in certain cases 1.
• Minimally invasive glaucoma surgery (MIGS) has gained popularity in recent years due to its reduced risk of complications and faster recovery time compared to traditional surgical methods 1.
• Laser procedures, such as selective laser trabeculoplasty (SLT), can be an effective treatment option for patients with open-angle glaucoma, as they can help reduce IOP and slow disease progression 1.
• The use of glaucoma drainage devices, such as Ahmed or Baerveldt implants, can be an effective treatment option for patients with refractory glaucoma or those who have undergone previous surgical procedures 1.
• Cataract extraction has also been shown to be an effective treatment in some patients with primary angle closure and primary angle closure glaucoma, as it can help reduce IOP and improve vision 1.

From the Research

Overview of Angle-Based Glaucoma Surgery

The primary surgical approaches for treating angle-based glaucoma include:

• Trabeculectomy: a surgical procedure that creates a new drainage path for fluid to leave the eye, reducing intraocular pressure (IOP) 2, 3
• Laser peripheral iridotomy: a laser procedure that creates a small hole in the iris, allowing fluid to flow more freely and reducing the risk of angle closure 4, 5
• Goniosynechialysis: a surgical procedure that removes scar tissue from the drainage angle, improving fluid flow and reducing IOP 5
• Lens extraction: a surgical procedure that removes the lens of the eye, which can help to reduce IOP and improve vision 4, 5

Surgical Approaches for Specific Types of Glaucoma

• Primary open angle glaucoma (POAG): trabeculectomy is a common surgical approach for POAG, especially when medical therapy is not effective 2, 3
• Primary angle closure glaucoma (PACG): laser peripheral iridotomy and goniosynechialysis are common surgical approaches for PACG, especially when there is evidence of angle closure 4, 5
• Acute angle closure glaucoma: laser iridoplasty and trabeculectomy are common surgical approaches for acute angle closure glaucoma, especially when medical therapy is not effective 5

Factors Influencing Surgical Outcomes

• Preoperative use of prostaglandin analogs: the use of prostaglandin analogs, such as bimatoprost, latanoprost, and travoprost, can affect the outcome of trabeculectomy 2
• Deepening of the upper eyelid sulcus (DUES): DUES is a complication that can occur with the use of prostaglandin analogs, and can affect the outcome of trabeculectomy 2
• Patient characteristics: factors such as age, gender, and ethnicity can influence the risk of glaucoma and the effectiveness of surgical treatment 5, 3