Perioperative antibiotics for prevention of acute endophthalmitis after cataract surgery

Methodological quality of the review: High confidence

Author: Gower EW, Lindsley K, Nanji AA, Leyngold I, McDonnell PJ.

Region: Pakistan, Turkey, Europe

Sector: Acute endophthalmitis, cataract surgery

Sub-sector: Perioperative antibiotics

Type of cataract: Age-related cataract

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Narrative analysis

Qualitative synthesis methods: Not applicable

Background

Endophthalmitis is a severe inflammation of the anterior and/or posterior chambers of the eye that may be sterile or associated with infection. It is a potentially vision-threatening complication of cataract surgery. Prophylactic measures for endophthalmitis are targeted against various sources of infection.

Research objectives

To evaluate the effects of perioperative antibiotic prophylaxis for endophthalmitis following cataract surgery.

Main findings

Four studies met the inclusion criteria for this review, including 100,876 adults and 131 endophthalmitis cases. While the sample size is very large, the heterogeneity of the study design and modes of antibiotic delivery made it impossible to conduct a formal meta-analysis. Interventions investigated in the studies included the utility of adding vancomycin and gentamycin to the irrigating solution compared with standard balanced saline solution irrigation alone, use of intracameral cefuroxime and/or topical levofloxacin perioperatively, periocular penicillin injections and topical chloramphenicol-sulphadimidine drops compared with topical antibiotics alone, and mode of antibiotic delivery (subconjunctival versus retrobulbar injections).

Two studies with adequate sample sizes to evaluate a rare outcome found reduced risk of endophthalmitis with antibiotic injections during surgery compared with topical antibiotics alone: risk ratio (RR) 0.33, 95% confidence interval (CI) 0.12 to 0.92 (periocular penicillin versus topical chloramphenicol-sulphadimidine) and RR 0.21, 95% CI 0.06 to 0.74 (intracameral cefuroxime versus topical levofloxacin). Another study found no significant difference in endophthalmitis when comparing subconjunctival versus retrobulbar antibiotic injections (RR 0.85, 95%CI 0.55 to 1.32). The fourth study which compared irrigation with balanced salt solution (BSS) alone versus BSS with antibiotics was not sufficiently powered to detect differences in endophthalmitis between groups. The risk of bias among studies was low to unclear due to information not being reported.

Authors noted that clinical trials with rare outcomes need to enrol large number of participants and are costly, and it is unlikely that additional clinical trials will be conducted to assess how well perioperative antibiotic prophylaxis works to prevent acute endophthalmitis after cataract surgery. They also stated that practitioners should consider the evidence shown here, that antibiotics injected into the eye are likely to reduce the risk of endophthalmitis after cataract surgery when they were sterilely obtained and delivered.

Methodology

Authors included randomized control trials, enrolling adults undergoing any type of cataract surgery and evaluating preoperative antibiotics, intraoperative or postoperative antibiotic prophylaxis for acute endophthalmitis. Primary outcomes included: (1) Endophthalmitis within six weeks after surgery and (2) Visual acuity measures.

Authors searched a number of databases including CENTRAL, MEDLINE, Ovid MEDLINE, Ovid OLDMEDLINE, EMBASE and LILACS and did not apply any date or language restrictions in the searches. For additional studies authors also searched Science Citation Index Expanded database. Two reviewers independently reviewed the titles and abstracts, extracted study characteristics and assessed the included studies for risk of bias.

Due to the heterogeneity of the four included studies, meta-analysis was not possible and a narrative synthesis of the results was conducted.

Applicability/external validity

The authors of the review recognized that two of the four studies included in the review are quite old and were conducted in the 1970s and 1980s. This meant that study findings would have less relevance today as cataract surgery practice has changed dramatically in the developed world. However, it should also be noted that these two studies were conducted in northern Pakistan in surgical camps, where intracapsular cataract extraction were performed and would, therefore, had relevance to low-income settings where that method of extraction and treatment settings were still common.

Geographic focus

Authors included studies from Pakistan, Europe, and Turkey. Please see above.

Quality assessment

High confidence in the conclusions about the effects was attributed to this study. This review is based on comprehensive searches, avoiding language bias. Authors used appropriate methods for screening, data extraction, critical appraisal and synthesis. The likelihood of bias within each study was addressed comprehensively.