Immediate sequential vs delayed sequential bilateral cataract surgery: systematic review and meta-analysis

Author: Aiello F, Gallo Afflitto G, Leviste K, Swaminathan SS, Yoo SH, Findl O, Maurino V, Nucci C

Geographical coverage: United States, Europe, Korea, and Iran.

Sector: Cataract treatment

Sub-sector: Complications

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: Cataract is the leading cause of global blindness and an important contributor to visual impairment in people aged 50 years and older. Advancement in surgical techniques and procedures have made cataract extraction highly effective with quick recovery. Previously, delayed sequential bilateral cataract surgery (DSBCS) was a standard technique which involved two surgeries spaced days or weeks apart. As an alternative approach, immediate sequential bilateral cataract surgery (ISBCS) performs both surgeries in a single session using complete aseptic separation. While ISBCS offers several benefits, including faster visual recovery, reduced costs, and fewer hospital visits, concerns persist regarding potential bilateral complications such as endophthalmitis. These associated risks have sparked debate among patients and physicians. Moreover, recent literature and data support re-evaluating the safety and efficacy of ISBCS compared to DSBCS.

Objectives: To compare the visual and refractive outcomes as well as the complication rate of endophthalmitis, cystoid macular oedema (CME), corneal oedema, and posterior capsule rupture (PCR) of immediate sequential bilateral cataract surgery (ISBCS) compared with delayed sequential bilateral cataract surgery (DSBCS).

Main findings: The review included 13 studies published between 2006 and 2022. Among these, 3 were randomised controlled trials (RCTs) and 10 were non-randomised studies (NRSs), both prospective and retrospective. The included studies were conducted in the United States (n=6), Europe (n=5), Korea (n=1), and Iran (n=1). The proportion of women was higher than men in both study types. Additionally, the AMD prevalence rate was higher in the DSBCS group compared with the ISBCS group, as reported in NRSs (P=0.0109). There was considerable heterogeneity across studies, especially in NRSs, with most NRSs having a serious risk of bias, primarily due to confounding factors and retrospective designs.

In RCTs, ISBCS showed a higher rate of achieving postoperative corrected distance visual acuity (CDVA) >20/40 compared to DSBCS (78.9% [95% CI: 75.5% to 82.0%] vs. 71.2% [95% CI: 67.5% to 74.7%], P=0.003). In NRSs, there was no significant difference was observed between ISBCS and DSBCS groups in achieving >20/40 CDVA (P=0.896).

Regarding refractive accuracy, no statistically significant differences were found in the proportion of eyes achieving a spherical equivalent within ±0.50 diopters of the target refraction in either RCTs (P=0.497) or NRSs (P=0.546), although slightly better outcomes were noted in the DSBCS group within NRSs.

Complication rates were generally low. Endophthalmitis was extremely rare, with no increased risk associated with ISBCS; notably, only one case of bilateral endophthalmitis occurred in the ISBCS group. Rates of pseudophakic cystoid macular oedema (CME) and corneal oedema were comparable between ISBCS and DSBCS, with no statistically significant differences. For posterior capsule rupture (PCR), RCTs showed no difference between the groups (P=0.5454), whereas NRSs indicated a slightly increased risk associated with ISBCS (risk ratio 1.34, P=0.0078).

Methodology:  The searches were conducted in Medline, Embase, and CENTRAL on April 24, 2022, to identify randomised and non-randomised studies conducted on adult patients with bilateral cataract, and comparing ISBCS and DSBCS. The studies were included if they were published in English and evaluated CDVA, postoperative SE, complication rate of endophthalmitis, persistent corneal oedema, pseudophakic CME, and PCR or tear with and without vitreous loss. Reference lists of the included studies were scanned to identify additional relevant publications.

Two reviewers independently screened the potentially relevant articles against the eligibility criteria. Disagreements between the reviewers were resolved by contacting a third reviewer. Two reviewers independently extracted the relevant data and contacted the investigating authors to obtain missing data or for seeking additional information. Two reviewers independently assessed the risk of bias in the included articles using Cochrane’s RoB-2 tool for randomised controlled trials and the ROBINS-I tool for non-randomised studies. Discrepancies between the reviewers were resolved through discussion.

The findings were synthesised using meta-analysis. Pooled estimates from randomised and non-randomised studies were presented separately. Heterogeneity was assessed using the Cochrane Q-test and I² statistics. The certainty of evidence per each outcome was assessed independently by two reviewers using the GRADE framework.

Applicability/external validity: The review included both RCTs and large-scale nonrandomised studies, thereby capturing data from diverse clinical settings and patient populations. However, the authors noted that the applicability of the findings may be limited due to the exclusion of high-risk patients in the RCTs and the potential for bias in the nonrandomised studies. Consequently, they advised interpreting the results with caution, as the evidence may not be fully representative of all patient groups and clinical scenarios.

Geographic focus: The authors did not apply any geographical limits. The included studies were conducted in the United States (n=6), Europe (n=5), Korea (n=1), and Iran (n=1).

Summary of quality assessment: Overall, there is medium confidence in the review’s conclusions. The search was limited to identifying articles published in the English language only, and the review did not provide a list of excluded studies.