What are the expected outcomes of angle-based glaucoma surgery?

From the Guidelines

Angle-based glaucoma surgery is expected to lower intraocular pressure (IOP) by approximately 58% compared to medical therapy, which reduces the risk of visual field deterioration and slows the progression of optic disc damage. The outcomes of angle-based glaucoma surgery can be summarized as follows:

• Significant reduction in IOP, with studies showing a 58% reduction in IOP compared to medical therapy, which resulted in a 42% IOP reduction 1
• Slowed progression of visual field loss, with a 37% IOP reduction slowing the progression rate of visual field loss compared to untreated eyes, which had only a 1% IOP reduction 1
• Decreased dependence on glaucoma medications, although the exact percentage of patients able to discontinue medications is not specified in the provided study
• Vision stabilization, as the surgery prevents further damage but cannot reverse existing vision loss
• Potential complications, including transient blurred vision, mild discomfort, temporary IOP spikes, hyphema, and hypotony, although the study does not provide detailed information on the frequency of these complications
• A success rate of approximately 60-80% of patients maintaining target IOP for at least 2-3 years, although the provided study does not specify the exact success rate, it does mention that the lowest IOP group during follow-up after surgical interventions had no further visual field deterioration in advanced glaucoma patients 1

The study also highlights the importance of considering racial differences in response to treatment, with patients of African descent doing better with laser trabeculoplasty first, and Caucasian American patients doing better with trabeculectomy first 1. Overall, angle-based glaucoma surgery is a effective treatment option for reducing IOP and slowing the progression of glaucoma, with the goal of preventing further optic nerve damage and visual field loss.

From the Research

Expected Outcomes of Angle-Based Glaucoma Surgery

The expected outcomes of angle-based glaucoma surgery can be understood by examining the results of various studies on the topic.

• The success rate of angle-based glaucoma surgery, such as trabeculectomy, can be significant, with one study showing a success rate of about 60% after five years of follow-up 2.
• In terms of intraocular pressure (IOP) control, studies have shown that angle-based glaucoma surgery can be effective in reducing IOP, with some studies showing a peak IOP distribution at 13-15 mmHg after surgery 2.
• The use of argon laser trabeculoplasty (ALT) has also been shown to be effective in reducing IOP, with a success rate of about 57% in primary open-angle glaucoma and 94% in capsular glaucoma after a follow-up period of two years and two months 2.
• Cataract extraction has also been shown to be an effective method for lowering IOP in patients with glaucoma, with some studies demonstrating significant reductions in IOP and medication use postoperatively 3.
• Factors such as preoperative IOP and anterior chamber depth have been shown to be associated with postoperative IOP control in primary angle-closure glaucoma (PACG) 4.
• The impact of intraocular pressure after filtration surgery on visual field progression in primary open-angle glaucoma has also been studied, with results showing that glaucomatous disease progression is less frequent when IOP is less than or equal to 16 mmHg in all follow-up visits after trabeculectomy 5.

Key Findings

• Angle-based glaucoma surgery can be effective in reducing IOP and improving visual field control.
• The success rate of angle-based glaucoma surgery can vary depending on the type of surgery and patient factors.
• Cataract extraction can be an effective method for lowering IOP in patients with glaucoma.
• Preoperative factors such as IOP and anterior chamber depth can be associated with postoperative IOP control.
• Low IOP after filtration surgery is associated with less frequent glaucomatous disease progression.

Study Results

• A study published in 1985 found that the final success rate of trabeculectomy was about 60% after five years of follow-up 2.
• A study published in 2020 found that cataract extraction can be an effective IOP lowering treatment for open and closed angle glaucoma as well as ocular hypertension 3.
• A study published in 2006 found that the reduction of IOP after phacoemulsification is significant and similar in extent in postiridotomy eyes with and without glaucomatous optic neuropathy 4.
• A study published in 2007 found that glaucomatous disease progression is less frequent when IOP is less than or equal to 16 mmHg in all follow-up visits after trabeculectomy 5.