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JAMA Ophthalmology Journal Club Slides:Trabeculectomy for Open-Angle Glaucoma

Takihara Y, 　 Inatani M, Ogata-Iwao M, et al. Trabeculectomy for open-angle glaucoma in phakic eyes vs pseudophakic eyes after phacoemulsification: a prospective clinical cohort study. JAMA Ophthalmol. Published online November 14, 2013. doi:10.1001/jamaophthalmol.2013.5605.

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Introduction

• Whether pseudophakic eyes are resistant to trabeculectomy remains unproven.

• Objective

– To determine the effect of previous phacoemulsification on surgical success of trabeculectomy with mitomycin C for open-angle glaucoma.

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• Prospective cohort study.

• Patients with open-angle glaucoma aged ≥55 years with intraocular pressure (IOP) ≥22 mm Hg were included. There were 39 phakic eyes (phakic group) and 25 pseudophakic eyes after phacoemulsification (pseudophakic group).

• Main Outcome Measure: Probability of success at 1 year after trabeculectomy. Surgical failure was defined according to the following criteria:

(A) IOP ≥21 mm Hg.

(B) IOP ≥18 mm Hg.

(C) IOP ≥15 mm Hg.

• The extent of surgical scarring in the conjunctiva due to prior phacoemulsification was not evaluated.

Methods

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• The probabilities of success at 1 year in the phakic and pseudophakic groups were 95% vs 74% for criterion A (P = .02), 84% vs 62% for criterion B (P = .04), and 67% vs 53% for criterion C (P = .10).

• Only pseudophakia was significantly associated with outcome in the multivariate analysis for criterion A (relative risk = 9.37) and criterion B (RR = 5.52) (P = .01 for both).

• Postoperative IOP in the pseudophakic group was significantly higher than that in the phakic group at 6 months (P = .03) and 9 months (P = .047) after trabeculectomy.

• No significant difference was noted in the number of postoperative antiglaucoma medications, laser suture lysis procedures, or surgical complications between both groups.

Results

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Results

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Results

Multivariable Analysis to Identify Prognostic Factors for Failure of Trabeculectomy Using Cox Proportional Hazards Regression Models

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• This study is unique in its prospective comparison between phakic eyes and pseudophakic eyes after phacoemulsification. In addition, the surgical procedure of trabeculectomy with mitomycin C was identical for all patients in this prospective study.

• The rate of surgical failure of trabeculectomy with mitomycin C in pseudophakic patients after phacoemulsification with open-angle glaucoma was higher than that in phakic patients with open-angle glaucoma. Also, patients in the pseudophakic group had a significantly lower cumulative probability of success for criterion A (P = .02) and criterion B (P = .04).

• For criterion C, no significant difference was found, although poorer surgical outcomes were observed in the pseudophakic group. The lack of statistical significance of the results for criterion C may be attributable to the small number of patients in this study. A larger study would determine the significance of this criterion.

Comment

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• The pathomechanism for failure of trabeculectomy in pseudophakic eyes is not fully understood.

• Alterations in the nature of the aqueous humor may contribute to surgical failure of trabeculectomy. Intraocular surgery causes ocular inflammation and breakdown of the blood-aqueous barrier, which may cause bleb failure after trabeculectomy. A higher concentration of inflammatory cytokines has been shown in aqueous humor in pseudophakic eyes with glaucoma. A recent prospective clinical study compared concentrations of monocyte chemoattractant protein 1 in the aqueous humor of patients with no eye diseases other than cataract before and after phacoemulsification. Monocyte chemoattractant protein 1 was upregulated in aqueous humor collected between 1 and 2 years after phacoemulsification; it recruits leukocytes in the anterior ocular segments, which may promote subconjunctival fibrosis and bleb scarring after trabeculectomy in pseudophakic eyes.

Comment

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• If you have questions, please contact the corresponding author:

– Masaru Inatani, MD, PhD, Department of Ophthalmology, Faculty of Medical Science, University of Fukui, 23-3 Shimoaizuki, Eiheiji, Yoshida, Fukui 910-1193, Japan (inatani@u-fukui.ac.jp).

Funding/Support

• This study was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology, Tokyo, Japan.

Conflict of Interest Disclosures

• None reported.

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