Presbyopia-correcting intraocular lenses implantation in eyes after corneal refractive laser surgery: a meta-analysis and systematic review

Authors: Sun Y, Hong Y, Rong X, Ji Y.

Geographical coverage: Europe, America, and Asia.

Sector: Biomedical

Sub-sector: Treatment

Equity focus: None

Study population: Cataract patients with previous corneal refractive surgery.

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: Laser refractive surgery is a common procedure for vision correction. Over time, patients who have undergone this surgery may develop cataracts earlier than those who haven’t. These patients, used to living without glasses, often desire to maintain their spectacle-independence post-cataract surgery. One solution is the use of presbyopia-correcting intraocular lenses (IOLs), which have been proven to restore near and intermediate vision and reduce dependence on glasses compared to monofocal IOLs. However, these IOLs can cause side effects like photic disturbances, decreased contrast sensitivity, and residual refractive errors, affecting patient satisfaction. Current research on the visual outcomes of presbyopia-correcting IOLs in post-refractive surgery cataract patients is limited.

Objectives: To assess the efficacy, safety and predictability of presbyopia-correcting intraocular lenses (IOLs) in cataract patients with previous corneal refractive surgery.

Main findings:

Overall, authors note presbyopia-correcting IOLs provide satisfactory results in terms of efficacy, safety and predictability in patients with previous corneal refractive surgery, but have a higher risk of photopic side effects such as halos and glare.

Thirteen studies were included in the final analysis. Nine were retrospective case series, and four were prospective studies with only three involving a control group. 128 patients and 445 eyes were identified. Seven studies were conducted in Europe, three in America, and three in Asia.

In terms of quality, two studies were assigned a level III rating and 12 were assigned a level IV rating. The mean MINORS score for non-comparative and comparative studies was 12.00 ± 0.85 and 19.67 ± 0.47, respectively, indicating fair quality of evidence for non-randomised studies and high quality for non-randomised studies. However, only one study reported prospective calculation of the study size and none had an unbiased assessment of the endpoints.

Analysis of the 13 studies showed that presbyopia-correcting IOLs were effective at improving distance, intermediate and near visual acuity after cataract surgery. The proportion of post-laser surgery eyes with uncorrected distance visual acuity (UDVA) ≥ 20/25 was 0.82 [95% confidence interval (CI), 0.74-0.90] and the pooled rates of spectacle independence at near, intermediate, and far distances were 0.98 (95% CI, 0.94-1.00), 0.99 (95% CI, 0.95-1.00) and 0.78 (95% CI, 0.65-0.94), respectively. The percentage of participants who suffered from halos and glare was 0.40 (95% CI, 0.25-0.64) and 0.31 (95% CI, 0.16-0.60), respectively. The predictability had a percentage of 0.66 (95% CI, 0.57-0.75) and 0.90 (95% CI, 0.85-0.96) of eyes within ±0.5 dioptres (D) and ±1.0 D from the targeted spherical equivalent.

Authors note the need for more evidence-based publications and RCTs, making a comparison between presbyopia-correcting IOLs and monofocal IOLs or among different types of the presbyopia-correcting IOLs; this warrants the provision of guidelines for IOLs selection in patients who have had corneal refractive surgery in the future.

Methodology:

Inclusion criteria were as follows: (1) population: patients who had corneal refractive laser surgery and subsequent cataract surgery or refractive lenses exchange; (2) intervention: presbyopia-correcting IOL implantation; (3) study design: observational studies, prospective or retrospective, randomised controlled trial (RCT), controlled, or case series; and (4) studies reported data on at least one of the following outcome measurement: efficacy, safety and predictability. Exclusion criteria included: (1) studies on analysis of IOL power calculation methods; and (2) eyes that have not in-the-bag fixed IOL implantation.

A literature search was performed in PubMed Medline, Ovid Medline, Web of Science, EBM Reviews (all Cochrane Library), Scopus-Health Sciences, ISI Web of Knowledge, EBSCO (Academic Search Complete, CINAHL and ERIC). A manual search of the reference lists of included articles and relevant systematic reviews was conducted to locate additional studies. There was no restriction on publication year, study design or language.

All titles and abstracts of papers identified by the search strategies were screened independently by two researchers and disagreements were resolved through discussions and consultations with a third investigator.

Two reviewers evaluated the quality of each included study using Methodological Index for Non-randomised studies (MINORS), and assigned a level of evidence based on the Oxford Centre for Evidence-based Medicine (CEBM). Data was extracted by two of the authors independently and combined by a third reviewer. If the data and the methods for obtaining it were considered relatively homogeneous, a meta-analysis was conducted. For continuous data like visual acuity, the mean values and standard deviations were extracted. For categorical data, the number of events were extracted.

The statistical analysis was carried out using the meta-package in R language. Statistical heterogeneity between studies was tested by means of a chi-square statistics with an I² value exceeding 50% and a p-value of <0.05 of statistical significance. In the absence of statistical heterogeneity, a fixed-effects model was used, otherwise a random-effects model was applied as the expected heterogeneity.

Applicability/external validity: Findings are likely to be less applicable due to weaknesses identified by authors in the nature of the included evidence, for example, much of it was of a moderate quality and not consistent in terms of the measurement of outcomes.

Geographic focus: While studies included some from Europe, Asia and America, it is unclear whether any were conducted in low- and middle-income countries. Furthermore, there was no consideration of how the reported findings might vary by geographical region.

Summary of quality assessment:

The approaches to identify, include and critically appraise studies were generally sound, although it is unclear whether a time limit was placed on the search. While the approach to the analysis of the data was also consistently robust, no attempts were made to exclude the included studies that were of a lower quality from the analysis specifically, to see whether this has any impact on the reported results. Coupled with the fact that many of the studies included in this review were of a moderate quality (as acknowledged by the authors themselves), this would lead us to have medium confidence in the findings of this review.