Effect of cataract surgery on the progression of age-related macular degeneration

Author: Chen Z, Zeng Y, Tian F.

Geographical coverage: Europe, Asia, the Americas, and Oceania

Sector: Cataract surgery

Sub-sector: Age-related macular degeneration

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background

Cataracts and age-related macular degeneration (AMD) are two of the most common causes of vision impairment in people aged over 50 years. While cataract surgery is the most effective treatment to improve vision, its potential impact on the progression of AMD has been debated for years. Some studies have suggested that cataract surgery may worsen AMD, particularly in the long term, while others have found no significant association. The overlap of these two conditions in older adults complicates the evaluation of surgical risks and benefits. Delaying cataract surgery negatively affects quality of life and could pose risks to retinal health. Inconsistent findings from various studies leave uncertainty around the true relationship between cataract surgery and AMD progression. Therefore, there is a need for more comprehensive analysis.

Objective

To evaluate the influence of cataract surgery on AMD.

Main findings

The review included eight studies. Of these, two were conducted in Europe, two in Asia, and the remaining in the Americas and Oceania. The patients in all studies were older than 42 years and were followed for between 3 months and 20 years. Methodologically, all studies were of high quality.

The findings revealed that cataract surgery and AMD progression were not significantly associated (relative risk [RR]: 1.194, 95% confidence interval [CI]: 0.897-1.591), and the difference was not statistically significant (Z = 1.21, P = 0.225). Subgroup analysis revealed increased risk more than five years after surgery (RR: 1.372, 95% CI: 1.062-1.772). Additionally, subgroup analysis showed a significant association between cataract surgery and AMD progression (RR: 4.50, 95% CI: 1.03-19.73).

Methodology

The searches were conducted in PubMed, SpringerLink, ClinicalKey, Medline, the Cochrane Library, Web of Science, Embase, and SinoMed from their inception up to May 2022. The review included cohort studies comparing visual acuity in AMD patients with or without cataract surgery and reporting the association between cataract surgery and AMD progression.

Two reviewers independently screened the articles. Disagreements between the reviewers were resolved by contacting a third reviewer. Relevant data were extracted, and the study quality of the included studies was assessed using the Newcastle-Ottawa Scale. The findings were synthesised using a fixed- or random-effects model meta-analysis based on heterogeneity. Heterogeneity was assessed using the Chi-square test and I² statistics, and publication bias was assessed using a funnel plot and Egger’s and Begg test. Subgroup analyses were performed. Sensitivity analysis was conducted to explore the impact of a single study on the overall results.

Applicability/external validity

The review acknowledged limitations affecting external validity, including heterogeneity in study populations, follow-up durations, and regional variability (e.g., stronger AMD progression risk in Asian cohorts). While the meta-analysis showed a significant positive correlation between cataract surgery and increased risk of worsening AMD progression, the authors were unable to draw definitive conclusions. The review emphasised the need for further clinical trials with sufficient statistical power.

Geographic focus

The review did not apply any geographical limits. The included studies were conducted in Europe, Asia, the Americas, and Oceania.

Summary of quality assessment

Overall, there is low confidence in the review’s conclusions. The searches were comprehensive. Inclusion and exclusion criteria were clearly defined, and two reviewers independently screened the articles, with disagreements resolved through consultation with a third reviewer. The study quality was assessed using established tools. Characteristics of included studies were well-documented, meta-analyses were appropriately performed, and heterogeneity was addressed. However, the review did not specify the number of reviewers independently involved in the data extraction, nor did it provide a list of excluded studies. It was unclear whether any language limits were applied. Additionally, the review did not report checking reference lists or contacting the authors or experts.