Efficacy and safety of manual small-incision cataract surgery with trabeculectomy versus phacotrabeculectomy in patients with glaucoma and cataract: a systematic review and meta-analysis

Author: Andini EA, Avianty A, Herman H, Choliq A

Geographical coverage: India and Indonesia

Sector: Glaucoma and cataracts

Sub-sector: Small-incision cataract surgery

Equity focus: Not reported

Study population: Adult patients with glaucoma

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

Cataracts cause lens clouding, and glaucoma leads to optic neuropathy and irreversible vision loss. They often occur together in older individuals. Surgery, especially for advanced glaucoma with high intraocular pressure (IOP), is a key treatment. Combining trabeculectomy with cataract surgery improves visual acuity and IOP management. Phacoemulsification and manual small-incision cataract surgery (MSICS) are preferable over extracapsular cataract extraction, but the best choice between MSICS with trabeculectomy and phacotrabeculectomy is still debated.

Objectives:

To evaluate the efficacy and safety of MSICS with trabeculectomy and compare it with phacotrabeculectomy for patients with both cataracts and glaucoma.

Main findings:

Overall, the review showed comparable efficacy and safety profile between MSICS with trabeculectomy and phacotrabeculectomy. It further reported no significant difference in postoperative IOP, postoperative best-corrected visual acuity (BCVA), complete success number, and postoperative complications between the two combined procedures.

The review included seven studies comparing manual small-incision cataract surgery with trabeculectomy (n=352 eyes) and phacoemulsification with trabeculectomy (n=348) eyes. The review identified no prospective study from the selection process. Six of the seven included studies were conducted in India, while one was conducted in Indonesia. The sample size in the included studies ranged from 10 to 97. One of the seven studies was deemed to have a high risk of bias due to not meeting one of the selection criteria in the Newcastle-Ottawa Quality Assessment Scale.

A total of seven studies were analysed to compare postoperative IOP, with no significant difference observed between the two groups (mean difference, (MD): -0.45; 95% confidence interval (CI): -1.07 to 0.16; p=0.15). Postoperative visual acuity, assessed categorically in three studies, also showed no statistically significant difference (odds ratio (OR): 1.26; 95% CI: 0.62 to 2.53; p=0.52). The complete surgical success rate, examined in three studies, revealed no significant difference between the two procedures (OR: 0.92; 95% CI: 0.51 to 1.67; p=0.78). Additionally, postoperative complications, reported in four studies, were analysed based on the number of affected eyes, with no significant difference in complication rates between the two surgeries (OR: 1.27; 95% CI: 0.75 to 2.15; p=0.38).

Methodology:

This review included studies and clinical trials on human subjects with any type of glaucoma and cataract, comparing MSICS-trabeculectomy and phacoemulsification-trabeculectomy. Relevant articles published up to March 2023 were identified through searches in PubMed, Science Direct, and Cochrane Library, as well as website searching and citation tracking. Two reviewers independently screened articles against eligibility criteria and assessed bias using the Newcastle-Ottawa Scale. Data included demographic characteristics and baseline and postoperative measures. A random-effects meta-analysis synthesised the data, reporting continuous outcomes with pooled MD and dichotomous outcomes with OR, both with 95% CI. Heterogeneity was evaluated using I² statistic, and publication bias was checked with a funnel plot.

Applicability/external validity:

The review authors pointed out the dependence on retrospective studies, which limits the strength of causal inferences. They also observed that all the included studies were conducted in Asia, possibly limiting the applicability of the results to other populations with different healthcare systems, surgical techniques, or genetic backgrounds. The authors noted variability in study methodologies, glaucoma subtypes, and surgical techniques as factors that could affect applicability. They suggested the need for prospective, randomised controlled trials across diverse populations to enhance the evidence and improve generalisability.

Geographic focus:

Included studies were conducted in India and Indonesia.

Summary of quality assessment:

Overall, we have low confidence in the review’s conclusions because of important methodological limitations. The search strategy covered only three bibliographic databases and did not describe grey-literature sources or trial registers; the authors did not report contacting study authors or experts, and no list of excluded studies was provided. Although they carried out basic citation tracking, the number of reviewers who extracted data was not stated, and the meta-analysis was not stratified by risk-of-bias status. The report also does not indicate whether non-English records were sought, so a language-bias risk cannot be ruled out.