Does Cataract Surgery Improve the Progression of Age-Related Macular Degeneration? A Meta-Analysis

Author: Liu Y, Cai Q.

Geographical coverage: Europe, Asia, Oceania and America

Sector: Cataract surgery

Sub-sector: Age-related macular degeneration

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis: Meta‑analysis

Qualitative synthesis: Not applicable

Background

Cataract and age‑related macular degeneration (AMD) are two leading causes of visual impairment in older people and often coexist in the same patient. Cataract surgery can effectively restore vision by removing the opacified lens, but there are concerns that it might accelerate the progression of AMD. Historical and recent clinical reports have suggested a higher incidence of neovascular AMD following cataract extraction. Some studies report an increased risk of AMD after surgery, whereas others find no association. The presence of AMD complicates surgical decision‑making, as delaying cataract surgery can also impair visual function. The debate continues, fuelled by inconsistent study designs and conflicting conclusions. Determining the impact of cataract surgery on AMD progression therefore remains an important clinical question.

Objective

To assess the effectiveness and safety of cataract surgery in eyes with age‑related macular degeneration.

Main findings

The review included eight cohort studies of high quality, conducted across Europe, Asia, America and Oceania. The pooled relative risk (RR) for AMD progression after cataract surgery was 1.194 (95 % confidence interval [CI] 0.897–1.591), indicating no statistically significant association. Subgroup analyses by geographic region showed notable differences. In Asian populations cataract surgery was associated with an increased risk of AMD progression (RR 2.855; 95 % CI 1.704–4.781). In contrast, there was no significant association in studies from Europe (RR 1.271, 95 % CI 0.914–1.769), Oceania (RR 1.017, 95 % CI 0.607–1.703) or America (RR 0.997, 95 % CI 0.621–1.601). Follow‑up duration also influenced the results: studies with follow‑up periods exceeding five years showed a higher risk of AMD progression after cataract surgery (RR 1.372; 95 % CI 1.062–1.772), whereas shorter follow‑up (five years or less) showed no significant association (RR 1.011; 95 % CI 0.592–1.728).

Methodology

Searches were performed in Medline, Embase and the Cochrane Library up to January 2019 to identify cohort studies published in English that reported on the relationship between cataract surgery and AMD. The reference lists of included studies and relevant articles were also screened for additional publications.

Two reviewers independently extracted data and assessed study quality using the Newcastle–Ottawa scale. Results were synthesised using a random‑effects meta‑analysis. Heterogeneity was evaluated with the chi‑squared test and I² statistics, and publication bias assessed with a funnel plot and Begg’s and Egger’s tests. Subgroup analyses were undertaken by geographical region and follow‑up duration, and sensitivity analysis examined the influence of individual studies on the overall effect estimate.

Applicability and external validity

The review did not explicitly discuss applicability and external validity. However, it noted important regional variations: in Asian populations cataract surgery was more strongly associated with AMD progression than in other groups, suggesting limited generalisability across ethnicities. The authors also observed that risks became apparent only with longer follow‑up (> 5 years), indicating a time‑dependent effect. Acknowledging the absence of randomised controlled trials — given the ethical difficulties of withholding surgery — they called for further research in under‑represented regions, using standardised protocols, to strengthen the evidence base.

Geographical focus

The review imposed no geographical limits; the included studies were conducted in Europe, Asia, Oceania and America.

Summary of quality assessment

Overall, confidence in the conclusions is low. Searches of Medline, Embase and the Cochrane Library up to January 2019 were comprehensive, inclusion and exclusion criteria were clearly defined and two reviewers independently extracted data and assessed study quality. Characteristics of included studies were well documented, meta‑analyses were appropriately performed and heterogeneity addressed. However, only cohort studies were included; the search was limited to English‑language articles; no list of excluded studies was provided; and the number of reviewers involved in screening was not specified. The review did not assess whether reference lists were checked or analyse findings according to risk‑of‑bias status.