Methodological quality of the review: Low confidence

Author: Ciulla TA, Starr MB, Masket S.

Region: Multiple countries, including Pakistan

Sector: Age-related cataract

Sub-sector: Surgery, prevention, clinical outcome

Type of cataract: Age-related cataract

Equity focus: None specified

Review type: Systematic review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis methods: Not applicable

Background

Postoperative endophthalmitis is an infrequent but serious complication of cataract surgery that often results in a poor visual outcome. There are a number of commonly used prophylaxis techniques aiming to decrease the incidence on endophthalmitis after cataract surgery. These are postoperative conjunctival antibiotics, preoperative lash trimming, preoperative saline irrigation, preoperative povidone-iodine antisepsis, preoperative topical antibiotics, irrigation solutions containing antibiotics and intraoperative heparin.

Research objectives

To review the commonly used cataract surgery bacterial endophthalmitis prophylaxis techniques and develop a series of recommendations.

Main findings

The authors included 88 published articles which fell into three categories: (1) studies designed to test the effect of a prophylactic intervention on the incidence of endophthalmitis in cataract surgery; (2) studies evaluation the effect of a prophylactic intervention on aqueous aspirate cultures; and (3) studies designed to test the effect of a prophylactic intervention on ocular surface flora.

These varied between retrospective, prospective, controlled, uncontrolled and experimental designs.

Of the seven commonly used prophylaxis techniques identified by the literature review, only one – preoperative povidone-iodine antisepsis – was rated moderately important and had a relatively strong evidence base. The evidence for all other techniques was weak and they received the lowest clinical recommendation. Of the latter, postoperative subconjunctival antibiotics had greater supporting evidence than the rest.

Preoperative preparation of the ocular surface with povidone-iodine is recommended by the authors for prophylaxis of bacterial endophthalmitis related to cataract surgery. It is possible that some other techniques, if properly studied, may also prove to be effective but they have not been adequately studied and reported. Due to the infrequent occurrence of this outcome, large, multicentre, masked, controlled, randomized investigations would have to be carried out to obtain strong supporting evidence.

After a reviewing the literature and evidence rating of all the commonly used cataract surgical  bacterial endophthalmitis prophylaxis techniques, authors concluded that only the preoperative preparation of the ocular surface with povidone-iodine was found to be moderately important in the reduction in the incidence of endophthalmitis and had a relatively strong evidence supporting it.

Methodology

Authors included articles pertaining to prophylaxis of bacterial endophthalmitis after cataract surgery, providing original data, in English or with English abstract, and published between 1966 and 2000. Earlier studies were included if considered relevant by all three authors. All study designs were considered.

Authors conducted a search on Medline database only including the terms: eye, endophthalmitis, prophylaxis, subconjunctival, antibiotic, saline, injection, irrigation, infusion, lash, povidone-iodine, topical, toxicity, aminoglycoside, quinoline, oral, ciprofloxacin, and ofloxacin.

All studies were scored with a double system: (1) Rated in the scale of A to C in the importance of the recommendation to clinical outcome; and (2) Rated in the scale of I to III in the strength of the supporting evidence for each recommendation

Applicability/external validity

The review addressed a group of studies that present controversial applicability: these are appropriately discussed in the appendix and refer to animal studies or experimental studies evaluating intraocular or surface flora or intraocular contamination in humans as opposed to the incidence of endophthalmitis after surgery.

Geographic focus

Although study inclusion was restricted to articles/abstracts written in English only, no geographic restriction was applied. At least one study from a low-income country (Pakistan) was included and is discussed in some detail in the review.

Quality assessment

This review covered a variety of interventions and study designs to identify the most commonly used prophylaxis techniques for cataract surgery. However, this review has major limitations. The search strategy was not reasonably comprehensive as only one database was searched; therefore we could not be confident that relevant literature was not omitted. Language bias and selection bias was not avoided within the review as the search was restricted to English articles/abstracts. Furthermore, no detailed reporting of the critical characteristics of all included studies was not reported. As such, low confidence was attributed in the conclusions about the effects of this study.