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Eur J Ophthalmol ( 2012 ; :4) 541-54622

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INTRODUCTION

Postoperative endophthalmitis is one of the most serious

complications of cataract surgery and may lead to severe

visual loss. The prevalence of postoperative endophthal-

mitis following cataract surgery is 0.06% to 0.68% (1).

A meta-analysis by Taban et al showed a significant in-

crease in postoperative endophthalmitis from 0.087% in

the 1990s to 0.265% for the 2000-2003 period (2). This up-

ward trend in the prevalence of postoperative endophthal-

Application of 10% povidone iodine reduces

conjunctival bacterial contamination rate in patientsundergoing cataract surgery

Martin M. Nentwich1, Mohammed Rajab1, Christopher N. Ta2, Lisa He2, Martin Grueterich1,

Christos Haritoglou1, Arnd Gandorfer1, Anselm Kampik1, Herminia Mino De Kaspar1,2

1Department of Ophthalmology, Ludwig-Maximilians-University, Munich - Germany2Department of Ophthalmology, School of Medicine, Stanford University, Stanford, California - USAD ep artmen tofO ph tha lmo logy ,Lu d wig -Max imilia ns-U niv ersit y ,Munic h-G e rma ny D ep artmen tofO ph tha lmo logy ,Sc hoo lofMe d icin e,S tan ford U n iv ers ity ,S tan ford ,C alifo rnia -U SAD ep artmen tofO ph tha lmo logy ,Lu d wig -Max imilia ns-U niv ersit y ,Munic h-G e rma ny D ep artmen tofO ph tha lmo logy ,Lu d wig -Max imilia ns-U niv ersit y ,Munic h-G e rma ny D ep artmen tofO ph tha lmo logy ,Lu d wig -Max imilia ns-U niv ersit y ,Munic h-G e rma ny D ep artmen tofO ph tha lmo logy ,Lu d wig -Max imilia ns-U niv ersit y ,Munic h-G e rma ny ;D ep artmen tofO ph tha lmo logy ,Sc hoo lofMe d icin e,S tan ford U n iv ers ity ,S ta nford ,C alifo rnia -U SAD ep artmen tofO ph tha lmo logy ,Lu d wig -Max imilia ns-U niv ersit y ,Munic h-G e rma ny

PURPOSE. To determine the efficacy of 10% povidone iodine (PVI) drops given before cataract extrac-

tion in addition to routine irrigation of the conjunctival sac with 1% PVI.

METHODS. This prospective, randomized, single-center study at the Department of Ophthalmology,

Ludwig-Maximilians-University, Munich, includes 263 eyes of 242 patients undergoing cataract sur-

gery. Patients were randomized to receive 3 drops of 10% PVI into the conjunctival sac (study group)

or no PVI drops (control group). All patients underwent periorbital disinfection with 10% PVI followed

by irrigation of the conjunctiva with 10 mL of 1% PVI. Specimens were obtained prior to the applica-

tion of PVI, after antibiotic administration (T1), after irrigation with PVI but before surgery (T2), and at

the conclusion of surgery (T3).

RESULTS. After PVI disinfection, the number of positive cultures was significantly reduced in all groups

(p

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10% Povidone iodine as prophylaxis before cataract surgery

stratified to outpatient and inpatient groups. All 112 eyes of

outpatients received one drop of topical neomycin (Alcon

Pharma, Freiburg, Germany) the hour prior to surgery while

151 eyes of inpatients received one drop of topical neomycin

4 times daily on the day prior to surgery and one drop in the

morning on the day of surgery. If surgery was scheduled in

the afternoon, the patients received a second drop of topicalneomycin before being transferred to the operating room.

Patients were randomized to the control and study groups.

In the preoperative area, the patients in the study group

received 3 drops of 10% PVI (Braunol; B. Braun, Melsun-

gen, Germany) in the conjunctival sac (in a single applica-

tion) while the control group received none. Afterwards,

all patients of both groups underwent standard periorbital

disinfection using 10% PVI scrub on the eyelids and sur-

rounding skin followed by application of gauze soaked

with 10% PVI on the closed lids for 5 minutes. After the

patient had been transferred into the operating room, theconjunctival sac was vigorously irrigated with 10 mL of

1% povidone iodine solution in both groups. Next, the

brow, upper and lower eyelids, eyelashes, and the adja-

cent forehead, nose, cheeks, and temporal orbital area

were again scrubbed with 10% PVI just prior to surgery.

The incubation time was identical in both groups to avoid

any confounding factor in this respect. Figure 1 summa-

rizes the infection prophylaxis regimen.

Conjunctival specimens from the surgery eyes were ob-

tained at the following time points: T1, prior to the application

of PVI but after the administration of topical neomycin antibi-

Povidone-iodine (PVI) antisepsis has proven to reduce

the risk of endophthalmitis following cataract surgery (6).

Due to the low prevalence of these cases, a prospective

randomized study evaluating the efficacy of any prophy-

lactic measure to reduce the actual risk of postoperative

endophthalmitis would require a very large number of pa-

tients and is impractical to perfom.In the current study, we compare 2 different methods of

preoperative application of PVI. The goal of this study was

to determine whether 10% PVI drops applied to the con-

junctival sac followed by irrigation of the conjunctival sac

with 1% PVI is superior in reducing conjunctival bacterial

contamination rate compared to 1% PVI irrigation alone.

MATERIALS AND METHODS

Consecutive patients undergoing cataract surgery were en-rolled in this prospective study. All surgeries were performed

at the Department of Ophthalmology, Ludwig-Maximilians-

University Munich from July to December 2008. The study

was approved by the Institutional Review Board of Ludwig-

Maximilians-University, Munich. Informed consent was ob-

tained from all patients prior to enrollment in the study.

In Germany, patients with significant medical illness such as

severe hypertension, poorly controlled diabetes mellitus, or

a history of stroke or myocardial infarction may be admitted

to hospital the day prior to cataract surgery. Because of the

difference in preoperative antibiotics regimen, patients were

Fig. 1 - Outline of the infection prophylaxis regimen. The individual steps in the preoperative infection prophylaxis regimen are illustrated. The

difference between the control and the study groups is shown in light gray. PVI = povidone iodine.

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Nentwich et al

lowing the application of PVI. For the outpatient group, there

was no difference at baseline (T1) cultures between the con-

trol group and the study group (p=0.25). There was a trend

in fewer positive cultures for the study group (17%) com-

pared to the control group (29%) following the application of

PVI (T2), but this was not statistically significant (p=0.1). At

the conclusion of surgery (T3), the study group had signifi-

cantly fewer positive cultures compared to the control group

(p=0.03); specifically, a fourfold difference (4% versus 16%).

For the inpatient group, the study group had a higher initial(T1) positive culture result compared to the control group,

86% versus 69%, respectively (p=0.01). However, following

the application of PVI, the study group had a significantly

lower positive culture rate compared to the control group

(12% versus 28%) (p=0.01). The patients in the study group

continue to have a lower culture-positive rate at the conclu-

sion of surgery, 1% versus 10% (p=0.03). Table I and Fig-

ures 2 and 3 summarize the results. Table II shows the p

value comparing different patient groups.

Bacteria isolated from the conjunctiva prior to PVI applica-

tion, in decreasing frequency, were coagulase-negative

otics; T2, following all the different applications of PVI, just pri-

or to surgery; T3, at the conclusion of surgery. All specimens

were obtained by the surgeon in masked fashion. The speci-

mens were inoculated and incubated in thioglycolate broth at

37C for 5 days. The microbiologist who interpreted the cul-

ture results was masked with regard to the patient group. In

all positive cultures, bacteria were isolated (first on blood agar

[Columbia agar with 5% sheep blood], MacConkey agar, and

on agar chromID-CPS3 agar), identified and tested for antibi-

otic susceptibility with Vitek2 Compact System (all materialswere obtained from bioMerieux, Marcy lEtoile, France), and

the results compared between the groups. Cross tab analysis

using chi-square test (SPSS for Windows, SPSS Inc., Chi-

cago, Illinois, USA) was performed to determine statistically

significant differences between the groups.

RESULTS

In all patients, there was significant reduction (p

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endophthalmitis. Table III demonstrates the distribution of

bacteria in the 2 patient groups at the different timepoints.

There was no obvious intraoperative and postoperative

toxicity from PVI, but the current study was not designed

to assess toxicity of PVI.

Staphylococcus 101/147 (68.7%), followed by Propioni-

bacterium acnes 26/147 (17.7%), -hemolytic Streptococ-

cus 7/147 (4.8%), Staphylococcus aureus 6/147 (4.1%),

Enterococcus faecalis 4/147 (2.6%), Micrococcus sp

1/147 (0.7%), -hemolytic Streptococcus 1/147 (0.7%),

andAerococcus urinae 1/147 (0.7%). There was no case of

TABLE II - p VALUES (CHI-SQUARE TEST)

Outpatients Inpatients

Control group Study group Control group Study group

T1 vs T2

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Nentwich et al

Despite all efforts to minimize the preoperative conjunctival

bacterial load, surgical instruments and aspirates of aque-

ous humor continue to show bacterial contamination. Ten

out of 39 (26%) microsurgical knives used for paracentesis

in cataract surgery were contaminated, while needles used

in strabismus surgery were contaminated in 15.1% and

19% according to 2 other studies (17-19).

A previously published study on 39 patients showed no differ-

ence between preoperative periorbital disinfection with 10%

PVI for 5 minutes and 5% PVI for 1 minute (10). In contrast,

our study suggest that the topical application of 3 additional

drops of 10% PVI directly into the conjunctival sac results in

a statistically significant greater reduction in the conjunctival

contamination rate than irrigation with 1% PVI alone.

The baseline cultures (T1) were similar between the control

group and the study group for the outpatient group but dif-

ferent for the inpatient group. The reason for this difference is

unclear as patients were randomized to the control and study

groups. We found no difference in the dosing of preoperative

antibiotics between the control and study groups (data not

shown). Despite an initially higher positive culture rate for the

study group at T1, the additional drops of 10% PVI resulted in

a greater reduction of conjunctival bacterial flora at T2 and T3,

as demonstrated by a significantly lower positive culture rate

for the study group compared to the control group.There are several limitations to our study. First of all, this

study provides only qualitative data (percentage of posi-

tive cultures), and therefore, no conclusions on the number

of colony-forming units can be drawn. Second, conjunctival

cultures were not obtained prior to the administration of anti-

biotics. However, since patients were randomized, we would

not expect a difference in the patient population between

the control and study group. Finally, as with many published

studies, ours focused on the conjunctival bacterial flora as a

surrogate marker for the risk for endophthalmitis. No studies

have proven a correlation between conjunctival contamina-tion and endophthalmitis and therefore, we cannot conclude

from our results regarding the actual risk of endophthalmitis.

Despite the limitations of our study, our results suggest

that additional drops of 10% PVI to the conjunctival sac

reduced the conjunctival contamination rate in patients un-

dergoing cataract surgery. This reduction is in addition to

the known efficacy of 10% PVI periorbital scrub and 1%

PVI irrigation of the conjunctiva. Further studies could be

considered to quantify the effects of 10% PVI drops on the

conjunctival bacterial flora relative to the risk of postopera-

tive endophthalmitis.

DISCUSSION

We performed this study in order to evaluate whether the

additional application of 3 drops of 10% PVI directly into

the conjunctival sac would reduce the conjunctival bacte-

rial contamination rate to a greater extent than the scrub-

bing of the eyelids and periorbital area with 10% PVI and

irrigation with 1% PVI. Our study of 263 eyes demonstrat-

ed that the addition of 3 drops of 10% PVI to the conjunc-

tival sac further reduced the rate of conjunctival cultures in

the perioperative period compared to 10% PVI periorbital

scrub and 1% PVI irrigation of the conjunctiva. This reduc-

tion was statistically significant at the conclusion of surgery

for the outpatient group. For the inpatient group, the study

group had significantly lower conjunctiva culture rate than

the control group following the application of PVI just prior

to surgery and at the conclusion of surgery. The incubation

time of PVI was identical in both groups to avoid any con-

founding factor in this respect. The safety of 10% PVI used

in the periorbital area has been described previously as

well as the use of 5% PVI on the ocular surface itself (7-12).

The bacteria identified at T1, which is after preoperative

antibiotic prophylaxis and before PVI disinfection, were

part of the normal conjunctival flora and similar to previ-

ously published studies of patients undergoing ocular sur-gery (13, 14). It is thought that the major source of post-

operative infections is the bacteria from the conjunctival

and eyelid flora of patients undergoing intraocular surgery.

Therefore, the preoperative reduction of the conjunctival

bacterial load may reduce the risk of postoperative endo-

phthalmitis. Povidone-iodine has been shown to be an ef-

fective and well-tolerated antiseptic in ophthalmic surgery

(7, 15). Apt et al demonstrated a reduction in numbers of

colonies by 91% and a decrease in the number of species

of 50% following the application of one drop 5% PVI in the

cul-de-sac (15). In a prospective study, Mio de Kaspar etal showed that irrigation of the fornices with 5% povidone-

iodine was associated with significantly fewer positive

conjunctival cultures at the time of surgery compared with

the application of 2 drops on the conjunctiva. This sug-

gests that irrigation of the conjunctival sac may be supe-

rior in reducing the conjunctival bacterial load (11). While

prospective studies have shown that topical antibiotics

in combination with PVI significantly reduce conjunctival

bacterial load, no study has been able to demonstrate that

the additional application of topical antibiotics reduces the

risk of postoperative endophthalmitis (16).

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comparative evaluation of povidone-iodine (10% for 5 min-

utes versus 5% for 1 minute) as prophylaxis for ophthalmic

surgery. J Cataract Refract Surg 2008; 34: 171-2.

11. Mio de Kaspar H, Chang RT, Singh K, Egbert PR, Blumen-

kranz MS, Ta CN. Prospective randomized comparison of

2 different methods of 5% povidone-iodine applications for

anterior segment intraocular surgery. Arch Ophthalmol 2005;

123: 161-5.

12. Trinavarat A, Atchaneeyasakul LO, Nopmaneejumruslers C,

Inson K. Reduction of endophthalmitis rate after cataract

surgery with preoperative 5% povidone-iodine. Dermatology

2006; 212(Suppl 1): S35-40.

13. Ta CN, Chang RT, Singh K, et al. Antibiotic resistance pat-

terns of ocular bacterial flora: a prospective study of patients

undergoing anterior segment surgery. Ophthalmology 2003;

110: 1946-51.

14. Park SH, Lim JA, Choi JS, Kim KA, Joo CK. The resistance

patterns of normal ocular bacterial flora to 4 fluoroquinolone

antibiotics. Cornea 2009; 28: 68-72.

15. Apt L, Isenberg S, Yoshimori R, Paez JH. Chemical prepa-

ration of the eye in ophthalmic surgery. III. Effect of po-vidone-iodine on the conjunctiva. Arch Ophthalmol 1984;

102: 728-9.

16. Ou JI, Ta CN. Endophthalmitis prophylaxis. Ophthalmol Clin

North Am 2006; 19: 449-56.

17. De Kaspar HM, Chang RT, Shriver EM, et al. Three-day ap-

plication of topical ofloxacin reduces the contamination rate

of microsurgical knives in cataract surgery: a prospective

randomized study. Ophthalmology 2004; 111: 1352-5.

18. Carothers TS, Coats DK, McCreery KM, et al. Quantification

of incidental needle and suture contamination during stra-

bismus surgery. Binocul Vis Strabismus Q 2003; 18: 75-9.

19. Olitsky SE, Vilardo M, Awner S, Reynolds JD. Needle sterility

during strabismus surgery. J AAPOS 1998; 2: 151-2.

Address for correspondence:

Dr. Martin M. Nentwich

Ludwig-Maximilians-UniversityDepartment of Ophthalmology

Klinikum der Universitt Mnchen

Campus Innenstadt

Mathildenstrasse 8

80336 Munich

Germany

[email protected]

ACKNOWLEDGEMENTS

Supported in part by Georg and Hannelore Zimmermann

Foundation, Germany.

The authors report no proprietary interest.

The data were presented in part at the 107th meeting of the German

Ophthalmological Society (DOG), Leipzig, Germany, September 24-

27, 2009.

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