Perioperative Antibiotics to Prevent Acute Endophthalmitis after Ophthalmic Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Post-operative endophthalmitis is a rare and dreaded complication in ophthalmic operations because it often induces irreparable vision loss. Although many ophthalmological studies aimed at reducing the rate of endophthalmitis have been performed around the world, controversy continues to surround some issues, including the choice of antimicrobials and their route of administration, duration and timing. The aim of this study is to investigate some of these unresolved issues.
METHODS: A systematic review and meta-analysis of randomized controlled trials and observational studies was performed. The PubMed, EMBASE, Cochrane Library and Clinical Trials databases were searched to identify studies published until Feb. 2016. The relative risk (RR) for each clinical outcome data is presented with 95% confidence intervals (CIs). Pooled estimates of effects were calculated using random-effect models.
RESULTS: Thirty-four studies from twenty-four reports involving 1264797 eyes were included in this analysis. Endophthalmitis occurred, on average, in one out of 6177 eyes when intracameral vancomycin/moxifloxacin were used and in one out of 1517 eyes when intracameral vancomycin/moxifloxacin were not used. The relative risk (95% CI) of endophthalmitis was reduced to 0.20 (0.10, 0.42) when intracameral antibiotics were used (p<0.0001). The subconjunctival injection of antibiotics was not superior to other administration routes included in this study (RR = 1.67, 95% CI (0.55, 5.05), p = 0.36). A statistically significant difference was found in the rate of endophthalmitis between the use and lack of use of topical antibiotics (RR = 0.65, 95% CI (0.43, 0.99), p = 0.04). However, no statistically significant difference was found in microbial isolation rates between these groups (RR = 0.77, 95% CI (0.34, 1.75), p = 0.53). When long-term and short-term use of topical antibiotics before surgery were compared, a statistically significant difference was found in microbial isolation rates (RR = 0.57, 95% CI (0.44, 0.74), p<0.0001).
CONCLUSIONS: This meta-analysis concluded intracameral antibiotics are effective at preventing endophthalmitis in ocular surgery. A randomized controlled trial confirms the efficacy of cefuroxime but recent large cohort studies support the efficacy of vancomycin/moxifloxacin intracamerally. Intracameral antibitoics are superior to subconjunctival injections but that irrigation antibitoic data are not of enough quality to make a comparison. Different results were found in two clinical outcomes between the use or lack of use of topical antibiotic therapy, we did not find sufficient evidence to conclude that its use prevents endophthalmitis.

Introduction

Post-operative endophthalmitis is a complication that can follow all ophthalmic procedures. Endophthalmitis is a calamitous event that can result in a patient suffering the loss of sight. Since 2000, the reported frequency of endophthalmitis is low worldwide, ranging from 0% to 0.63% [1]. Coagulase-negative Staphylococcus species are the organisms that are most frequently isolated from patients who develop postoperative endophthalmitis after cataract surgery. It is followed by coagulase-positive Staphylococcus species, Streptococcus species, Enterococcus species, and Corynebacterium species [2-7]. In pars plana vitrectomies, the reported bacteria include coagulase-negative Staphylococcus species, Pseudomonas species, Propionibacterium species, Enterococcus species, and Bacillus species [8]. Preoperative, intraoperative, and postoperative risk factors have been reported by some ophthalmologists. Diabetes mellitus, an immunocompromised state, chronic blepharitis, lacrimal passage infection, contaminated eyedrops, contact lens use, contralateral prosthesis and gender are preoperative factors, while the application of 2% xylocaine gel before povidone-iodine instillation, prolonged surgery, secondary surgery, posterior capsular rupture, vitreous loss and contaminated irrigating solution are intraoperative factors. Wound leakage, vitreous incarceration and behaviors (e.g., eye rubbing and personal hygiene) are associated with the development of post-operative endophthalmitis [9]. To reduce its incidence, many measures have been employed by ophthalmologists around the world. These include the use of topical antibiotics, intracameral antibiotics, subconjunctival antibiotic injections, lash trimming, saline irrigation, and antibiotic-containing irrigating solutions. However, the most frequent measure is the use of povidone–iodine before surgery to decrease contamination by ocular microbes and prevent postoperative endophthalmitis [10-12]. Not all of these techniques have been found to influence clinical outcomes. Intracameral cephalosporin (cefazolin, cefuroxime) has been shown to be effective in randomized controlled trials and meta-analyses [13-14]. An increasing number of ophthalmologists have supported the use of intracameral cefuroxime to prevent postoperative endophthalmitis because of the ESCRS study. However, as a result of the severe drug resistance of the causal bacteria, some new intracameral antibiotics, such as vancomycin and moxifloxacin, have been suggested to avoid endophthalmitis [15-21]. The subconjunctival injection and topical application of antibiotics have also been used by some ophthalmology centers, but the results of different reports have varied. This paper focuses on the use of intracameral vancomycin/moxifloxacin and the subconjunctival injection and topical application of antibiotics. The timing of topical drops was also analyzed. We sought to use a systemic review and meta-analysis to discuss those controversial issues.

Materials and Methods

Search Strategy

A comprehensive literature search was performed to identify studies published until Feb. 2016. The PubMed, EMBASE, Cochrane Library, and Clinical Trials databases were the main sources that were searched. Other routes (e.g., hand-search and library resource sharing) were also considered. Ophthalmologic surgical procedures, cataract extractions, vitrectomies, keratoplasties, intraocular lens implantations, glaucoma procedures, strabotomies, retinal detachment repair, laser in situ keratomileusis, laser-assisted subepithelial keratectomy, antimicrobial, antibacterial agents, antibiotic prophylaxis, anti-infective agent and eye surgery were the search terms that were used. The specific searching strategy is described in S1 Table.

Inclusion and Exclusion Criteria

Studies were included if they met the following criteria: (i) random studies and observational studies, (ii) compared endophthalmitis rates or microbial isolation rates in two comparable populations, (iii) received/did not receive intracameral vancomycin/moxifloxacin therapy, or received/did not receive subconjunctival antibiotic injection, or received/did not receive topical antibiotics or compared administration with different timing, (iv) published from January 2000-February 2016 (reduced the influence of new operations), and (v) exceeded 1000 individuals if the study reported endophthalmitis rates and 50 if it reported microbial isolation rates. Studies were excluded if they: (i) were not written in English, (ii) were incomplete or included duplicated data, (iii) did not contain any predetermined clinical outcomes, (iv) could not be pooled with other included studies, (v) did not instill topical antibiotics (in terms of the group received topical antibiotics), and (vi) had no conformity at baseline with other studies in the timing (antibiotic drops and povidone–iodine were administered before surgery) and site of the analyzed specimen (conjunctival sac).

Data extraction

The data were extracted independently by two authors (JZH and XHC). A standardized form was designed before the extraction to collect information including first author, publication date, mean age, male (%), type of surgery, study design, follow-up time, no. of eyes, therapeutic regimen, timing and clinical outcomes. If disagreements arose between these two authors, all final decisions were made by LCL and QYS after a discussion.

Quality assessment

Randomized controlled trials (RCT) and observational studies were included in our analysis, and the quality assessment of those data is described in the S1 File. Observational studies were evaluated using the Newcastle–Ottawa scale (NOS) [22]. Nine items comprised the check list, and every item accounted for 1 point in each of three parts (selection, comparability and exposure). If a score was larger than 6, the study was determined to be of high quality. RCTs were assessed using the recommendations of the Cochrane Collaboration [23].

Outcomes analyzed

In the current data set, the rate of endophthalmitis was the best and most direct clinical outcome that could be used to measure the effect of prophylactic antimicrobial agents. However, because postoperative endophthalmitis is rare, some studies also selected the microbial isolation rate as their outcome. In the analysis in this study, the rate of endophthalmitis was used as the primary outcome, and the microbial isolation rate was the secondary outcome.

Statistical analysis

In this meta-analysis, we used risk ratios (RR) with 95% confidence intervals (CIs) to present dichotomous outcomes or enumeration data and random-effect models to calculate pooled estimates of effects. In light of fact that the rate of endophthalmitis was low, in case-control studies, the odds ratio (OR) was considered to be approximately equal to the RR. The I2 statistic was used to assess heterogeneity among studies. We considered the I2 values from 0% to 24%, 25% to 50% and greater than 50% to indicate low, moderate and high heterogeneity, respectively [23]. To decrease heterogeneity and increase reliability, a subgroup analysis was performed for every comparable group. Forest plots, the risk of bias in randomized controlled trials and the above-mentioned traits were analyzed using RevMan version 5.1. Furthermore, the analyses to determine sensitivity and publication bias analysis using Stata version 12.0.

Results

Results of the search and study characteristics

Up to February 2016, a total of 688 reports were identified through database searches, and 34 studies included in 24 reports involving 1264797 eyes were included in the final analysis [2, 13, 15–21, 24–38]. The detailed screening process is described in Fig 1. Of the remaining reports, there were nine RCTs [13, 30–37] and fourteen observational studies [2, 15–21, 24–29, 38]. A total of 21 studies reported the rate of postoperative endophthalmitis [2, 13, 15–21, 24, 27–29, 38], and 13 studies reported the microbial isolation rate [25, 26, 30–37]. Thirty studies [2, 13, 15–21, 24, 27–30, 33–37, 38] included only eyes that received cataract surgery, but an additional four studies [25–26, 31–32] included other intraocular surgeries. The characteristics of the included studies are shown in Table 1.

Fig 1

Flow diagram showing the selection process used to include studies in the meta-analysis.

Table 1

Main characteristics of the studies included in the meta-analysis.

First Autdor, Date

Age

Male(%)

Type of Surgery

Study Design

Follow-up Time

No. of Eyes

Tderapeutic Regimen

Timing

Clinical Outcomes

Tde Quality of tde Study

T

C

T

C

T

C

Intracameral Antibiotic VS No Intracameral

Rush,2015

71.0

49.4

CAS

COS

3 months

9386

11333

IC vancomycin, PVI

PVI

PE

PE

RPE

High

Anijeet,2010

NA

NA

CAS

COS

6 weeks

12702

3904

IC vancomycin, PVI

PVI

PE

PE

RPE

Moderate

Rudnisky,2014

NA

NA

CAS

CCS

6 weeks

11818

59739

IC vancomycin

No intracameral antibiotic

PE

PE

RPE

Moderate

Rudnisky,2014

NA

NA

CAS

CCS

6 weeks

3738

59739

IC moxifloxacin

No intracameral antibiotic

PE

PE

RPE

Moderate

Shorstein,2013

74.0

NA

CAS

CCS

12 months

1890

3655

IC moxifloxacin, PVI

PVI

PE

PE

RPE

Moderate

Haripriya,2016

NA

NA

CAS

COS

6 weeks

38160

78554

IC moxifloxacin, PVI

PVI

PE

PE

RPE

High

Matsuura,2013

NA

NA

CAS

COS

1 month

18794

15958

IC moxifloxacin, PVI

PVI

PE

PE

RPE

Moderate

Friling,2013a

NA

38.3

CAS

COS

10 months

6897

2804

IC moxifloxacin, PVI

PVI

PE

PE

RPE

High

Galvis,2014

67.2

NA

CAS

COS

2 weeks

1618

1056

IC moxifloxacin, PVI

PVI

PE

PE

RPE

Moderate

Subconjunctival Injection Antibiotic VS No Subconjunctival Injection

Jabbarvand,2016b

79.0

NA

CAS

RCS

6 weeks

69120

25290

SI antibiotic +PVI

IC+PVI

PE

PE

RPE

Moderate

Jabbarvand,2016c

79.0

NA

CAS

RCS

6 weeks

69120

76800

SI antibiotic +PVI

topical antibiotic +PVI

PE

PE

RPE

Moderate

Jabbarvand,2016d

79.0

NA

CAS

RCS

6 weeks

69120

260744

SI antibiotic +PVI

PVI

PE

PE

RPE

Moderate

Asencio,2015

71.5

NA

CAS

CCS

6 weeks

5068

9217

SI gentamicin +PVI

Irrigation BBS+ vancomycin+ gentamicin +PVI

PE

PE

RPE

High

Tan,2012

NA

NA

CAS

COS

1 month

29539

20638

SI gentamicin+ cefazolin +PVI

IC cefazolin +PVI

PE

PE

RPE

Moderate

Yu-Wai,2008

NA

NA

CAS

COS

3 weeks

19425

17318

SI cefuroxime +PVI

IC cefuroxime +PVI

PE

PE

RPE

Moderate

Colleaux,2000b

NA

NA

CAS

COS

NA

8856

5030

SI gentamicin ± cefazolin

PVI +Topical antibiotic

PE

PE

RPE

Moderate

Topical Antibiotic VS No Topical Antibiotic

ESCRS,2007a

NA

NA

CAS

RCT

6 weeks

4000

3997

Topical levofloxacin +IC cefuroxime +PVI

Placebo +IC cefuroxime +PVI

PE

PE

RPE

High

ESCRS,2007b

NA

NA

CAS

RCT

6 weeks

3984

3990

Topical levofloxacin +PVI

Placebo +PVI

PE

PE

RPE

High

Coskun,2011a

NA

51.2

CAS

RCT

NA

54

53

Topical ciprofloxacin

PVI

PE

PE

MIR

Moderate

Coskun,2011b

NA

51.2

CAS

RCT

NA

57

53

Topical ofloxacin

PVI

PE

PE

MIR

Moderate

Eyal,2009

69.7

48.9

OCS

RCT

72 hours

237

227

Topical moxifloxacin +PVI

PVI

PE

PE

MIR

Moderate

First Author, Date

Age

Male(%)

Type of Surgery

Study Design

Follow-up Time

No. of Eyes

Therapeutic Regimen

Timing

Clinical Outcomes

The Quality of the Study

T

C

T

C

T

C

Kaspar,2008

67.8

34.1

OCS

RCT

10 days

67

65

Topical levofloxacin +PVI

PVI

PE

PE

MIR

High

Colleaux,2000a

NA

NA

CAS

COS

NA

12152

1734

Topical Tobramycin or Gentamicin or Ofloxacin or Polymyxin-trimethoprim

SI antibiotic +PVI

PE

PE

RPE

Moderate

Friling,2013b

NA

NA

CAS

COS

10 months

7307

396894

Topical chloramphenicol or fusidic acid

IC antibiotic +PVI

PE

PE

RPE

High

Jabbarvand,2016a

79.0

NA

CAS

RCS

6 weeks

76800

260744

Topical ciprofloxacin +PVI

PVI

PE

PE

RPE

Moderate

Long time VS Short Time of Topical Antibiotic

Bing,2015

70.6

50.4

CAS

RCT

5 days

69

64

Topical neomycin/polymyxin-B

Topical neomycin/polymyxin-B

1d

1h

MIR

Moderate

Inoue,2008a

74.0

46.3

CAS

RCT

5 days

79

76

Topical levofloxacin

Topical levofloxacin

3d

1h

MIR

Moderate

Inoue,2008b

74.0

46.3

CAS

RCT

5 days

79

89

Topical levofloxacin

Topical levofloxacin

3d

1d

MIR

Moderate

Inoue,2008c

74.0

46.3

CAS

RCT

5 days

89

76

Topical levofloxacin

Topical levofloxacin

1d

1h

MIR

Moderate

Lingmin,2009

71.1

50.8

OCS

RCT

10 days

57

63

Topical moxifloxacin

Topical moxifloxacin

3d

1d

MIR

Moderate

Ta,2002

NA

NA

CAS

RCT

10 days

43

48

Topical ofloxacin

Topical ofloxacin

3d

1h

MIR

High

Ta,2007

NA

NA

CAS

RCT

6 days

50

50

Topical levofloxacin

Topical levofloxacin

3d

1d

MIR

High

Christopher,2008

69.3

68.3

OCS

COS

5 days

60

60

Topical moxifloxacin

Topical moxifloxacin

1d

1h

MIR

Moderate

Jason,2008

67.7

58.3

OCS

COS

5 days

60

60

Topical gatifloxacin

Topical gatifloxacin

1d

1h

MIR

Moderate

Footnotes:Age: Mean age or median age.

Abbreviations: NA = not available, T = treatment group, C = control group, CAS = cataract surgery, OCS = ocular surgery, COS = cohort study, CCS = case-control study, RCT = randomized controlled trial, RCS = retrospective cross-section study, IC = intracameral, SI = subconjunctival injection, PVI = povidone-iodine, PE = perioperation, 1d = 1 day before surgery, 3d = 3 days before surgery, 1h = within 1 hour before surgery, RPE = rate of postoperative endophthalmitis, MIR = microbial isolation rate.

The Rate of Postoperative Endophthalmitis

Intracameral Antibiotic

Nine studies compared patients who received/did not receive intracameral vancomycin/moxifloxacin therapy [15–21, 38]. A significant difference was found in the meta-analysis results, which suggested that the rate of postoperative endophthalmitis was lower in the intracameral vancomycin/moxifloxacin group (OR = 0.20, 95% CI (0.10, 0.42), p<0.0001, I2 = 45%) (Fig 2A). In the subgroup analysis, the results in the moxifloxacin group was homologous (OR = 0.21, 95%CI (0.12, 0.37), p<0.00001, I2 = 0%) (Fig 2A). However, there was heterogeneity in the vancomycin group (OR = 0.11, 95%CI (0.01, 1.55), p = 0.10, I2 = 81%) (Fig 2A).

Fig 2

Forest plot of the Rate of Postoperative Endophthalmitis (A: the effect of including and not including Intracameral Antibiotics; B: the effect of using VS not using subconjunctival antibiotic injections; C: the effect of using VS not using Topical Antibiotics). The vertical line indicates no difference between the groups. RRs are represented by diamond shapes, and 95% CIs are depicted by horizontal lines. Squares indicate point estimates, and the size of each square indicates the weight of the given study in the meta-analysis. M-H, Mantel-Haenszel random-effects model.

Subconjunctival antibiotic injections

Seven studies reported the use of subconjunctival antibiotic injections [2, 24, 27–29]. When patients who received subconjunctival antibiotic injections were compared to those who did not, no significant difference was found (OR = 1.67, 95% CI (0.55, 5.05), p = 0.36, I2 = 85%) (Fig 2B). Because I2 = 85%, three subgroup analyses were performed to increase reliability. The results suggested that a significant difference was found between the subconjunctival antibiotic injections group and the intracameral antibiotic and irrigation groups (intracameral antibiotic: OR = 3.76, 95% CI (1.92, 7.37), p = 0.0001, I2 = 0%; irrigation: OR = 10.07, 95% CI (3.09, 32.88), p = 0.0001) (Fig 2B). When the subconjunctival antibiotic injection group was compared to the topical or PVI (povidone-iodine) group, there was no significant difference (OR = 0.43, 95% CI (0.15, 1.20), p = 0.11, I2 = 68%) (Fig 2B).

Topical Antibiotic

The meta-analysis results revealed that there was a significant difference among the five studies (2, 13, 20, 24) that reported the rate of postoperative endophthalmitis (OR = 0.65, 95% CI (0.43, 0.99), p = 0.04, I2 = 0%) (Fig 2C). However, when subgroups were analyzed, no significant difference was found except for in a retrospective study (OR = 0.49, 95% CI (0.26, 0.89), p = 0.02) (Fig 2C).

Microbial Isolation Rate

There were four studies [30-32] that provided a microbial isolation rate, and the results of these studies suggested that there was no significant difference (OR = 0.77, 95% CI (0.34, 1.75), p = 0.53, I2 = 72%) (Fig 3A). A subgroup analysis was performed, but the results were similar (only topical antibiotic: OR = 0.74, 95% CI (0.17, 3.27), p = 0.69, I2 = 83%; topical antibiotic + PVI: OR = 0.77, 95% CI (0.19, 3.09), p = 0.71, I2 = 77%) (Fig 3A).

Fig 3

Forest plot of the Microbial Isolation Rate (A: the effect of using VS not using Topical Antibiotics; B: the effect of Long-term VS Short-term use). The vertical line indicates no difference between the groups. RRs are represented by diamond shapes, and 95% CIs are depicted by horizontal lines. Squares indicate point estimates, and the size of each square indicates the weight of the given study in the meta-analysis. M-H, Mantel-Haenszel random-effects model.

Timing

When long-term and short-term use of a topical antibiotic before ocular surgery was analyzed, nine studies that had consistent baselines were included (25–26, 33–37). The meta-analysis revealed that short-term use was associated with an increased incidence of microbial isolation (OR = 0.57, 95% CI (0.44, 0.74), p<0.0001, I2 = 40%) (Fig 3B). Because there was moderate heterogeneity (I2 = 40%), a subgroup analysis was performed. A significance difference was found in the group that included two RCTs and that compared application between three days and within one hour before surgery (OR = 0.40, 95% CI (0.26, 0.63), p<0.0001, I2 = 0%) (Fig 3B). A significance difference was also found in the group that included two non-RCTs and that compared results between groups that were administered at one day and within one hour before surgery (OR = 0.56, 95% CI (0.39, 0.80), p = 0.002, I2 = 0%) (Fig 3B). There was no difference between the other two subgroups (3 days VS 1 day, RCT: OR = 0.57, 95% CI (0.32, 1.02), p = 0.06, I2 = 41%; 3 days VS 1 day, RCT: OR = 0.76, 95% CI (0.44, 1.32), p = 0.36, I2 = 49%) (Fig 3B).

Publication Bias and Sensitivity Analysis

There was no significant publication bias according to the Begg’s and Egger’s funnel plot asymmetry tests that were performed in the meta-analysis (S2 File). The results of the sensitivity analysis were diverse, and the details are described in S3 File. In the group comparison between using and not using intracameral antibiotics, sensitivity was not influenced by the studies that were omitted obviously. The sensitivity analysis for receiving or not receiving subconjunctival antibiotic injections demonstrated that three studies (Colleaux,2000b, Jabbarvand,2016c and Jabbarvand,2016d) influenced the pooled effect size, and these studies were therefore deleted. New results that were similar to those of the subgroup analysis revealed that intracameral and irrigation antibiotics were superior to subconjunctival injections. In the case of topical antibiotics, we excluded the study (Jabbarvand, 2016a) because it influenced the sensitivity in the group that used RPE as a clinical outcome. When we then reanalyzed the data, we found that there was no statistical difference. Hence, that study should be deleted to increase the conclusion’s reliability. In the group in which MIR was used as the outcome, we re-conducted a subgroup analysis according to classifications of quinolone, but the result was similar to the previous result. The sensitivity analysis for the timing of application of topical antibiotics demonstrated that the study (Inoue, 2008c) exhibited slightly more influence on the pooled effect size than other studies, and this study was therefore deleted. The new result was almost the same as the initial result, but the heterogeneity was smaller. Because of the variety of available antibiotics, we also reanalyzed new subgroups according to the classifications of the drugs that were used. The result was similar to the previous result, but the heterogeneity was larger.

Discussion

The low rate of postoperative endophthalmitis makes it difficult to conduct a large RCT to investigate the optimal method for preventing it [39]. Based on the currently available clinical evidence, preoperative preparation with 5% povidone-iodine solution has consensus approval among ophthalmologists. However, no consensus has been reached regarding the agent of choice, the administration route or the timing of antimicrobial prophylaxis, and no agent has been FDA-approved for this indication in ophthalmic procedures [1]. For these reasons, we performed this meta-analysis. However, because of the absence of relevant RCTs, we also included observational studies to resolve the problem mentioned above in this analysis. Since the ESCRS study, intracameral antibiotics have gradually gained acceptance around the world. Of those antibiotics, cefuroxime has been shown to be effective at reducing the rate of postoperative endophthalmitis. However, with the increase in resistant microorganisms, moxifloxacin and vancomycin have received an increasing amount of attention. The results of this meta-analysis show that intracameral moxifloxacin/vancomycin can prevent endophthalmitis. Unfortunately, no RCTs were included to address this point. Additionally, no study compared the use of cephalosporin with moxifloxacin or vancomycin. In addition to intracameral moxifloxacin/vancomycin, we also compared the results of administering subconjunctival antibiotic injections via other routes. According to our analysis, intracameral antibiotics were superior to subconjunctival injections, but subconjunctival injections were not superior to topical antibiotics or PVI. There is only one case-control study to compare irrigation antibiotics with subconjunctival injections, so the data is not enough quality to make a comparison. According to the results of this meta-analysis, we do not recommend subconjunctival antibiotic injections as a routine method for preventing endophthalmitis. Interestingly, when the timing of administration was not considered, topical antibiotics seemed to lose their value. The results were the same whether RPE or MIR was used as the clinical outcome. But there was a higher incidence of microbial isolation in short-term use than long-term use patients. The reason for this contradictory result might be that the efficiency of bacterial eradication varied with differences in the timing of topical antibiotics use. However, reducing the number of bacteria on the ocular surface is not the same as preventing endophthalmitis. Additionally, many topical antibiotics are used in combination, which makes it difficult to determine optimal timing [1]. The timing reported in the papers ranged from one hour to three days before the surgery [4, 11, 40–41]. Further investigations should be performed to optimize the best regimens. Given the results we obtained in the meta-analysis and the results from the ESCRS study, the use of topical antibiotics was not recommended.There are several limitations to our meta-analysis. First, few RCTs were included. Second, although we performed subgroup and sensitivity analyses, the I2 values remained large, especially in the topical antibiotic group, demonstrating that heterogeneity was high. The fact that we did not identify the reason for the heterogeneity may make the results unreliable. Third, some results were obtained from small sample studies. In addition, difficulties in diagnosing and defining endophthalmitis could also influence the primary data. For the studies that selected MIR as the clinical outcome, the method and duration of specimen cultivation might have made the results in the primary studies more diverse, which could have influenced our results.In conclusion, intracameral vancomycin/moxifloxacin therapy is effective for preventing postoperative endophthalmitis. Intracameral antibiotics are superior to subconjunctival injections, but that irrigation antibitoic data are not of enough quality to make a conclusion. Different results were found for topical antibiotic therapies between two clinical outcomes, and we did not find sufficient evidence to conclude that this technique prevents endophthalmitis. Long-term use of topical antibiotics before surgery appears to be more effective, but clearance the number of pathogens on the ocular surface is not the same as preventing endophthalmitis. So, topical antibiotics before surgery to prevent endophthalmitis were not recommended by this meta-analysis.

PRISMA Checklist for the meta-analysis.

(DOC)

Click here for additional data file.

Quality assessment of included studies.

(DOCX)

Click here for additional data file.

Publication bias.

(DOCX)

Click here for additional data file.

Sensitivity analysis.

(DOCX)

Click here for additional data file.

Search strategy.

(DOC)

Click here for additional data file.