Comparison of Visual Acuity and Complications Between Primary IOL Implantation and Aphakia in Patients with Congenital Cataract Younger Than 2 Years: A Meta-Analysis

Author: Chen J, Chen Y, Zhong Y, Li J. 

Geographical coverage: India, China, the Czech Republic, the UK, and in multicentre settings

Sector: Cataracts

Sub-sector: Visual acuity and 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

Congenital cataract is the leading cause of childhood visual impairment and blindness, with an estimated prevalence of 4 to 5 per 10,000 children. It typically appears at birth or during early childhood and requires timely intervention to sustain normal visual development. While cataract extraction with intraocular lens (IOL) implantation is standard for children over 2 years, younger patients are often managed with contact lenses or spectacles. However, challenges such as poor cooperation, risk of infection, and higher cost make contact lens usage difficult. In recent years, primary IOL implantation in children (under 2 years of age) has gained attention as a possible alternative. Some researchers argue that it offers permanent correction and supports visual development, while others raise concerns about potential complications such as glaucoma and visual axis opacification. Therefore, to extract a conclusive outcome, a comprehensive evaluation is essential to inform clinical decision-making.

Objective

To evaluate visual acuity and complications between the primary IOL implantation group and the contact lens-wearing aphakia group after cataract extraction in patients with congenital cataract younger than 2 years.

Main findings

The review included seven studies: three RCTs, one cohort study, and three comparative studies. Overall, 675 eyes (337 in the aphakia group and 338 in the IOL group) were analysed. Two studies were performed in India, one in China, one in the Czech Republic, and one in the United Kingdom, while the remaining two were multicentre. The follow-up durations ranged from 1 to 5 years, and methodological quality varied across the studies.

The meta-analysis showed that vision after primary IOL implantation was significantly better than after contact lens use (weighted mean difference, WMD = 0.161, 95% confidence interval [CI]: 0.108 to 0.214, P = 0.0001). However, no statistically significant difference was found between the two groups for the occurrence of glaucoma (relative risk, RR = 1.30, 95% CI: 0.63 to 2.67, P = 0.478).

Additionally, the findings indicated an increased incidence of visual axis opacification (VAO) with primary IOL implantation compared with contact lens use (RR = 0.23, 95% CI: 0.13 to 0.42, P = 0.0001). However, there was no difference in the occurrence of strabismus between the two groups (RR = 1.06, 95% CI: 0.91 to 1.24, P = 0.436).

Methodology

The searches were conducted in PubMed, Web of Science, EMBASE, Cochrane Library, and Google Scholar to identify studies on patients with congenital cataract who underwent cataract extraction, either with primary IOL implantation or contact lens use. Studies published in English up to March 2019 were included.

Two reviewers independently screened the articles. Disagreements between the reviewers were resolved through discussion or by contacting a third reviewer. Relevant data were extracted, and the quality of the included studies was assessed using the Cochrane Collaboration’s tool for risk of bias. Findings were synthesised using meta-analysis. Heterogeneity was evaluated using the Q-test and I² statistics, and publication bias using a funnel plot. Subgroup analysis was performed by study design, and sensitivity analysis was conducted to explore the effect of a single study on the overall results.

Applicability/external validity

The review did not explicitly discuss the applicability or external validity of its findings. However, it acknowledged variability in surgical techniques, IOL types, and follow-up durations, as well as the risk of selection bias, due to the inclusion of studies from multiple countries and designs. The authors emphasised the need for multicentre, randomised clinical trials with long-term follow-up to further clarify the conclusions.

Geographic focus

The review did not apply any geographical limits. The included studies were conducted in India, China, the Czech Republic, the UK, and in multicentre settings. It was not specified whether multicentre studies were conducted within a single country or across multiple countries.

Summary of quality assessment

Overall, there is low confidence in the review’s conclusions. The searches were conducted in multiple databases. Inclusion and exclusion criteria were clearly defined, and two reviewers independently screened the articles, with disagreements resolved through discussion or 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 search was limited to English-language articles. The review did not provide a list of excluded studies, nor did it report checking reference lists or contacting authors. Additionally, the review did not specify how many reviewers independently performed data extraction, and did not analyse findings by risk of bias status.