Medical prophylaxis and treatment of cystoid macular oedema after cataract surgery: The results of a meta-analysis

Methodological quality of the review: Medium confidence

Author: Rossetti L, Chaudhuri J, Dickersin K.

Region: Not specified

Sector: Age-related cataract

Sub-sector: Clinical outcomes, complications

Type of cataract: Age-related cataract

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis methods: Not applicable

Background

Cystoid macular oedema (CME) remains a troublesome problem after cataract surgery and other types of ocular surgical procedures and its aetiology is not clear. Available therapeutic interventions, both for prophylaxis and for treatment of CME, are based on theories regarding the pathogenesis of the condition. Studies testing the efficacy of these interventions generally have not been well designed or conducted, and results have been inconsistent. The study aimed to determine the effectiveness of prophylactic medical intervention in reducing the incidence of cystoid macular oedema (CME) and the effectiveness of medical treatment for chronic CME after cataract surgery.

Research objectives

To determine whether prophylactic medical intervention is effective in reducing the occurrence of CME and consequently in preventing visual loss in aphakic and pseudophakic patients.

To determine whether medical therapy is an effective treatment in patients with chronic CME. 

Main findings

Sixteen randomized controlled trials (RCTs) involving 2,898 eyes examining the effectiveness of medical prophylaxis of CME, and four RCTs involving 187 eyes testing the effectiveness of medical treatment of chronic CME were included in the study. Geographical location of included studies was not specified by the authors.

Summary odds ratios (OR) indicated that prophylactic intervention was effective in reducing the incidence of both angiographic CME (OR = 0.36; 95% confidence interval [Cl] = 0.28-0.45) and clinically relevant CME (OR = 0.49; 95% Cl = 0.33- 0.73). There also was a statistically significant positive effect on improving vision (OR = 1.97; 95% Cl = 1.14-3.41). A combination of the results of the four RCTs testing medical therapy for chronic CME indicated a treatment benefit in terms of improving final visual acuity by two or more Snellen lines (OR = 2.67; 95%Cl = 1.35-5.30).

The meta-analysis of the results from the RCTs suggested that medical prophylaxis for aphakic and pseudophakic CME and medical treatment for chronic CME after cataract surgery is beneficial. However, there were limitations on the quality and in the outcomes considered by the RCTs included.

Authors noted that there was a need for additional data using clinical CME and vision as outcomes. Study design should be correctly addressed in future research in the topic.

Methodology

Authors included published RCTs of CME after cataract surgery evaluating (1) the effectiveness of prophylactic medical intervention effectiveness in reducing the occurrence of CME and evaluating (2) the effectiveness of medical therapy treatment in chronic CME lasting for at least six months.

Authors conducted a search on MEDLINE (1966-1996) for RCTs. Studies written in other than English, French and German were excluded from the review. As part of the search strategy, authors also reviewed references of included articles for further studies. The results of the searches were screened; abstracts were reviewed by one of the authors to select potentially relevant studies. Data were extracted by two authors and entered into a form to assess design and methodological quality of included studies.

Applicability/external validity

The authors do not address the applicability/external validity of the results.

Geographic focus

Authors did not discuss the geographical location of included studies. The review included all studies in English, German and French, without specific focus to low- or middle-income countries. CME was a common complication of cataract surgery in all settings and the conclusions of the review would be relevant to cataract surgery in low- and middle-income countries.

Quality assessment

Authors conducted a search of the literature in one relevant database only and limited the search to articles written in English, French and German; these restrictions may indicate the presence of publication and language bias within the review. Nevertheless, these limitations were openly discussed within the review. Although data extraction was conducted by two reviewers, screening of potential articles was performed by one reviewer only, consequently inducing selection bias. Despite of the limitations of the review, this review was attributed medium confidence in the conclusions about the effects of this study.