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Lens extraction may have a role in reducing IOP in patients with primary angle-closure or primary angle-closure glaucoma.
Reviewed by Anjali M. Bhorade, MD
St. Louis-There might be a role for lens extraction in certain scenarios for patients with primary angle-closure (PAC) or primary angle-closure glaucoma (PACG). This question is being addressed in the effectiveness of early lens extraction with IOL implantation for the treatment of PACG in the EAGLE study.
“In such patients, the lens plays a major role in the pathogenesis of PAC and PACG. Those with the former have thicker lenses that are positioned more anteriorly and a decreased anterior chamber angle,” Anjali Bhorade, MD, commented.
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However, she pointed out that the current studies of angle closure and cataract surgery are limited in that few patients were included, many studies were nonrandomized, and the methodologies varied greatly, making comparisons among the studies extremely difficult.
In her attempt to determine if cataract surgery is beneficial in this patient population, she wanted to evaluate patients based on whether their cataracts were visually relevant, she explained. Those with visually relevant cataracts typically undergo a laser peripheral iridotomy (LPI) and if the IOP is controlled medically, the patients are monitored.
Managing visually relevant cataracts in PAC
However, there is a question about the appropriateness of managing these patients with phaco-trabeculectomy or phacoemulsification. Dr. Bhorade, associate professor of ophthalmology, Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, recounted a study conducted by Tham and colleagues (Ophthalmology 2008; 115: 1267-73) in which 72 eyes with medically controlled IOP and a visually relevant cataract following a LPI were randomized to phacoemulsification or a phaco-trabeculectomy.
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The results showed that the IOP decreased in both groups, but the difference between them did not reach statistical significance. The group with the combination therapy had fewer IOP medications but more postoperative complications compared with phacoemulsification alone.
“If there are patients with a visually significant cataract whose IOP is medically controlled but they would like to decrease their medications, phacoemulsification might be a good choice,” she said.
If the IOP is medically uncontrolled after an LPI, Dr. Bhorade considers the same treatment scenario for these patients. Dr. Tham and colleagues also performed a study (Ophthalmology 2009; 116: 725-31) that included 51 eyes with uncontrolled IOP despite medical therapy and a visually relevant cataract. In this group, the combination therapy significantly lowered the IOP compared with the phacoemulsification group.
However, the result was the same as in the previously described group: Fewer IOP medications were needed postoperatively but there were more postoperative complications. “Cataract surgery alone might be indicated in these patients,” she said.
Another therapeutic course to consider is cataract surgery versus LPI as the initial treatment. In two previous studies, the eyes were randomized to one of the treatments. In one study (Ophthalmology 2008; 115: 1134-40), the mean IOP was lower in the phacoemulsification group than in the LPI group; in the second study (Ophthalmology 2012; 119: 2274-81), the 2-year cumulative survival rate was 89.5% in the phacoemulsification group compared with 61.1% in the LPI group.
“It appears that initial cataract surgery in patients with visually significant cataracts might be an appropriate treatment,” Dr. Bhorade commented.
Managing nonvisually relevant cataracts in PAC
This management scenario-in which patients have nonvisually relevant cataracts and medically uncontrolled IOP after a LPI-is less clear. A 2013 study (Ophthalmology 2013; 120: 62-7) by Tham and colleagues looked at the results in patients who were randomized to phacoemulsification or trabeculectomy. The patients in both groups had similar IOP reductions before and after surgery. The results with trabeculectomy, as reported previously, showed the need for fewer medications but more complications developed. One-third of patients developed a visually relevant cataract. “After an LPI, cataract surgery in a patient with a nonvisually significant cataract with uncontrolled IOPs might be appropriate at times,” she said.
When considering lens extraction as an initial treatment in a patient with a nonvisually relevant cataract, Dr. Bhorade recounted a study (Ophthalmology 2002; 109: 1597-603) by Jacobi and colleagues of 43 eyes treated with either phacoemulsification or surgical PI. The investigators reported that the IOPs were significantly lower in the phacoemulsification group than in the PI group. However, more studies are needed to confirm this result.
Finally, a Cochrane review of retrospective and prospective studies indicated that there was a lack of evidence from any highly qualified randomized clinical trials to support if early lens extraction is superior to other treatments (Cochrane Databse Syst Rev 2006; 3:CD005555. DOI: 10.1002/14651858.CD005555.pub2).
The EAGLE Study
The 31-site, randomized EAGLE Study (Trials 2011; 12: 133. DOI: 10.1186/1745-6215-12-133) evaluated if patients with PAC or PACG benefited from early lens extraction by analyzing if the patient reports, clinical measures, or cost effectiveness improved.
The participating patients were 50 years or older with newly diagnosed PACG or PAC and IOPs over 30 mm Hg. The angle closure was 180 degrees or more and patients had a nonvisually relevant cataract. The patients were randomized to lens extraction or a LPI and followed for 3 years. The primary outcomes were the patient-centered health status determined by the EQ-5D questionnaire, the IOP at 3 years, and the incremental cost per quality-adjusted life year gained. The results are forthcoming.
Dr. Bhorade summarized, “Based on what is known thus far about cataract surgery and its appropriateness for patients with PAC and PACG…some studies have suggested that cataract surgery may be an appropriate treatment to lower IOP [in patients with a visually significant cataract]. In patients with a nonvisually significant cataract, cataract surgery may be appropriate after a patient has had an LPI and the IOP remains uncontrolled. However, the role of cataract surgery as an initial treatment for PAC/PACG in a patient with a nonvisually significant cataract remains unclear. Results from the EAGLE study may help clarify this answer.”
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Anjali M. Bhorade, MD
This article was adapted from Dr. Bhorade’s presentation at the 2016 meeting of the American Glaucoma Society. Dr. Bhorade has no financial interest in the subject matter.