Immediate sequential bilateral surgery versus delayed sequential bilateral surgery for cataracts

Age-related cataract affects both eyes in most cases. Most people undergo cataract surgery in both eyes on separate days, referred to as delayed sequential bilateral cataract surgery (DSBCS). An alternative procedure involves operating on both eyes on the same day, but as two separate procedures, known as immediate sequential bilateral cataract surgery (ISBCS). Potential advantages of ISBCS include fewer hospital visits for the patient, faster visual recovery, and lower healthcare costs. Nevertheless, concerns exist about possible bilateral, postoperative, sight-threatening adverse effects with ISBCS. Therefore, there is a clear need for evaluating evidence regarding the safety, effectiveness, and cost-effectiveness of ISBCS versus DSBCS.

To assess the safety of ISBCS compared to DSBCS in people with bilateral age-related cataracts and to summarise current evidence for the incremental resource use, utilities, costs, and cost-effectiveness associated with the use of ISBCS compared to DSBCS in people with bilateral age-related cataracts (primary objectives). The secondary objective was to assess visual and patient-reported outcomes of ISBCS compared to DSBCS in people with bilateral age-related cataracts.

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 5); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov; the WHO ICTRP; and DARE and NHS EED on the CRD Database on 11 May 2021. There were no language restrictions. We limited the searches to a date range of 2007 onwards.

We included randomised controlled trials (RCTs) to assess complications, refractive outcomes, best-corrected distance visual acuity (BCDVA) and patient-reported outcome measures (PROMs) with ISBCS compared to DSBCS. We included non-randomised (NRSs), prospective, and retrospective cohort studies comparing ISBCS and DSBCS for safety assessment, because of the rare incidence of important adverse events. To assess cost-effectiveness of ISBCS compared to DSBCS, we included both full and partial economic evaluations, and both trial-based and model-based economic evaluations.

We used standard Cochrane methodological procedures and assessed risk of bias for NRSs using the ROBINS-I tool. For cost-evaluations, we used the CHEC-list, the CHEERS-checklist, and the NICE-checklist to investigate risk of bias. We assessed the certainty of evidence with the GRADE tool. We reported results for economic evaluations narratively.

We included 14 studies in the review; two RCTs, seven NRSs, and six economic evaluations (one study was both an NRS and economic evaluation). The studies reported on 276,260 participants (7384 for ISBCS and 268,876 for DSBCS) and were conducted in Canada, the Czech Republic, Finland, Iran, (South) Korea, Spain (Canary Islands), Sweden, the UK, and the USA. Overall, we considered the included RCTs to be at 'high to some concerns' risk of bias for complications, 'some concerns' risk of bias for refractive outcomes and visual acuity, and 'high' risk of bias for PROMs. The overall risk of bias for NRSs was graded 'serious' regarding complications and 'serious to critical' regarding refractive outcomes.  With regard to endophthalmitis, we found that relative effects were estimated imprecisely and with low certainty, so that relative estimates were not reliable. Nonetheless, we found a very low risk of endophthalmitis in both ISBCS (1/14,076 participants) and DSBCS (55/556,246 participants) groups. Based on descriptive evidence and partially weak statistical evidence we found no evidence of an increased risk of endophthalmitis with ISBCS. Regarding refractive outcomes, we found moderate-certainty (RCTs) and low-certainty (NRSs) evidence there was no difference in the percentage of eyes that did not achieve refraction within 1.0 dioptre of target one to three months after surgery (RCTs: risk ratio (RR) 0.84, 95% confidence interval (CI) 0.57 to 1.26; NRSs: RR 1.02, 95% CI 0.60 to 1.75). Similarly, postoperative complications did not differ between groups (RCTs: RR 1.33, 95% CI 0.52 to 3.40; NRSs: 1.04, 95% CI 0.47 to 2.29), although the certainty of this evidence was very low for both RCTs and NRSs. Furthermore, we found low-certainty (RCTs) to very low-certainty (NRSs) evidence that total costs per participant were lower for ISBCS compared to DSBCS, although results of individual studies could not be pooled. Only one study reported on cost-effectiveness. This study found that ISBCS is cost-effective compared to DSBCS, but did not measure quality-adjusted life years using preferred methods and calculated costs erroneously. Finally, regarding secondary outcomes, we found limited evidence on BCDVA (data of two RCTs could not be pooled, although both studies individually found no difference between groups (very low-certainty evidence)). Regarding PROMs, we found moderate-certainty evidence (RCTs only) that there was no difference between groups one to three months after surgery (standardised mean difference -0.08, 95% CI -0.19 to 0.03).

Current evidence supports there are probably no clinically important differences in outcomes between ISBCS and DSBCS, but with lower costs for ISBCS. However, the amount of evidence is limited, and the certainty of the evidence was graded moderate to very low. In addition, there is a need for well-designed cost-effectiveness studies.