Corneal Edema after Cataract Surgery

Author: Briceno-Lopez C, Burguera-Giménez N, García-Domene MC, Díez-Ajenjo MA, Peris-Martínez C, Luque MJ.

Geographical coverage: Not reported

Sector: Cataract Surgery

Sub-sector: Risk of corneal oedema

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background

Corneal oedema is defined as excessive stromal hydration due to dysfunction of the endothelial pump and barrier, leading to reduced transparency and impaired vision. The primary cause is endothelial damage during cataract surgery (phacoemulsification), with contributing factors including patient age, cataract density, surgical technique, and mechanical stress. Chronic oedema may progress to bullous keratopathy, necessitating keratoplasty. This review focuses specifically on post-cataract surgery oedema, analysing endothelial cell loss, diagnostic tools (e.g., pachymetry, OCT), and unresolved questions about refractive changes.

Objective

To investigate and understand the cause and prevalence of the occurrence of corneal oedema after manual phacoemulsification in cataract surgery.

Main findings

The review included 103 studies (41 clinical trials and 62 theoretical articles). The included studies were conducted in different countries and published over a range of years. Study designs varied, and sample sizes ranged from small pilot studies to large randomised controlled trials.

The findings revealed significant correlations between corneal oedema and endothelial cell loss during phacoemulsification surgery. Factors such as patient age, cataract grade, and mechanical stress were identified as contributors to endothelial cell loss. Furthermore, pachymetry and optical coherence tomography emerged as valuable diagnostic tools for assessing corneal oedema. Overall, the results emphasised the importance of preoperative assessment and surgical precision to minimise endothelial damage and postoperative complications.

Methodology

The searches were conducted in PubMed, Embase, ProQuest, Cochrane Library, and Scopus up to 31st December 2022 to identify relevant articles published in English, French, Spanish, Catalan, Portuguese, or Italian. The studies were included if they involved patients aged 50 years and older with cataracts in one or both eyes, and described the oedema process, its characterisation, medical treatment, or physiological corneal changes in the presence of corneal oedema. The reference lists of the relevant review articles were also scanned to identify additional relevant publications.

Two reviewers independently screened the articles, extracted the relevant data and critically appraised the quality of the included studies using the Cochrane risk of bias tool for clinical trials and the Newcastle-Ottawa Scale for theoretical studies. Disagreements between the reviewers were resolved through discussion or by contacting a third or fourth reviewer. The findings were synthesised narratively.

Applicability/external validity

The review did not explicitly discuss the external validity of its findings, however, it highlighted variability in surgical techniques and outcome measurements across studies. The authors acknowledged potential publication bias and language restrictions as limitations, which could affect the generalisability of conclusions. The review highlighted the need for further research in this area.

Geographic focus

The review did not apply any geographical limits. However, it did not report the geographical distribution of the included studies.

Summary of quality assessment

Overall, there is medium confidence in the review’s conclusion. The searches were comprehensive. Inclusion and exclusion criteria were clearly defined, and two reviewers independently screened the articles, extracted data, and assessed the study quality using established tools, with disagreements resolved through discussion or consultation with a third and fourth reviewer. Findings were synthesised narratively. However, language limits were applied. The review did not provide a list of excluded studies. Characteristics of the included studies were not reported, and the findings were not analysed by the risk of bias status.