Impact of Ocular Compression on Ocular Surface Bacterial Contamination

doi:10.4236/ijcm.2013.49067

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International Journal of Clinical Medicine, 2013, 4, 375-377

http://dx.doi.org/10.4236/ijcm.2013.49067 Published Online September 2013 (http://www.scirp.org/journal/ijcm) 375

Impact of Ocular Compression on Ocular Surface

Bacterial Contamination

Amir Reza Daneshmand Eslami1*, Nikolai M. Sergienko1, Ivan P. Bilko2

1Department of Ophthalmology, National Medical Academy of Postgraduate Education, Kiev, Ukraine; 2Department of Microbiol-

ogy and Epidemiology, National Medical Academy of Postgraduate Education, Kiev, Ukraine.

Email: *[email protected]

Received June 12th, 2013; revised July 16th, 2013; accepted August 5th, 2013

tribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is prop-

erly cited.

ABSTRACT

Background: To study the impact of preoperativ e ocular compression on bacterial contamination of the lid margin and

conjunctival sac. Methods: This study evaluated 106 eyes from 106 patients undergoing cataract surgery. Preopera-

tively, all of the patients received one drop of 0.5% levofloxacin eye drops 5 times per day for 4 days. The patients were

divided into 2 groups after receiving retrobulbar anaesthesia. The study group (75 eyes) received 15 ± 2 minutes of

ocular compression, and the control group (31 eyes) remained with their eyes closed for 15 ± 2 minutes without the ap-

plication of ocular compression or digital massage. Following the device removal (study group only) and the opening of

the eyes, bacterial cultures were taken from the lid margin and conjunctival sac. Results: The lid margin was positive

for bacteria in 23 eyes (30.7%) in the study group vs. 3 eyes (9.7%) in the control group (P = 0.0223), and the con junc-

tival sac was positive for bacteria in 16 eyes (21.3%) in the study group vs. 5 eyes (16.1%) in the control group (P =

0.5409). Conclusion: Preoperative ocular compression is associated with the release of meibomian gland secretions and

bacterial contamination of the eyelid edges.

Keywords: Bacteria; Conjunctival Sac; Endophthalmitis; Lid Margin; Ocular Compression

1. Introduction

Postoperative endophthalmitis (POE) remains a rare but

severe complication in modern cataract surgery [1]. The

most common sites of ocular bacterial contamination

leading to POE include the eyelids, skin and conjunctiva

[2,3]. The lid margins, which carry bacterial flora to the

skin surface, and meibomian gland secretions also play

an important role in POE development. However, it

remains unclear whether preoperative ocular compres-

sion (OC), which is performed to reduce intraocular pres-

sure (IOP), can promote bacterial contamination of the

eyelids and conjunctiva. Although in recent years OC has

become less popular, this technique is still commonly

performed. Pressure delivered via the modified Honan’s

balloon is realised not on ly on the eyeball but also on the

lid margin and may provoke the release of meibomian

gland secretions that contain bacteria.

The aim of this study was to determine the impact of

preoperative ocular compression on bacterial contamina-

tion in the lid margin and the conjunctival sac.

2. Materials and Methods

2.1. Study Sample

This study evaluated 106 eyes from 106 patients under-

going cataract surgery. The exclusion criteria included

systemic or local infection, con junctivitis, b lepharitis, da-

cryocystitis, meibomian gland dysfunction and diabetes

mellitus. Preoperatively, all of the patients received one

drop of 0.5% levofloxacin ophthalmic solution (Ofta-

quix®, Santen Oy, Niittyhaankatu 20, 33720 Tampere,

Finland) 5 times per day for 4 days.

The patients were placed in the supine position prior to

treatment and remained undisturbed throughout the test

period. Retrobulbar anaesthesia was administered with a

single injection of 0.5% bupivacaine hydrochloride, 2%

lidocaine hydrochloride, and 0.5% hyaluronidase (3.75

IU/ml). The volume of the block ranged from 3.5 to 5.5

ml, depending on the patient’s weight.

The patients were divided into two groups. The study

group (75 eyes of 75 patients) received retrobulbar

anaesthesia in addition to the preoperative application of

*Corresponding a uthor.

Impact of Ocular Compression on Ocular Surface Bacterial Contaminat i on

376

OC (approximately 30 mm Hg) for 15 ± 2 minutes using

a modified Honan’s balloon, and the control group (31

eyes of 31 patients) received retrobulbar anaesthesia

without the preoperative application of OC or digital

massage. In the control group, the patients’ eyes re-

mained closed for 15 ± 2 minutes after the anaesthesia

administration. Approval for accessing the patient health

records was obtained from the local research ethics

committee. Informed consent was obtained from each

patient. The study protocol and the safety and efficacy of

the intervention s were explained to all of the participants

prior to their enrolment.

2.2. Bacteriological Investigation

After the specified period of 15 ± 2 minutes and follow-

ing the device removal (study group only), the eyes were

opened, and bacterial cultures from the conjunctival sac

and lid margin were immediately initiated using sterile

cotton swabs moistened with sterile saline solution. In

addition, swabbing was performed for the lower lid

margin by rolling the swab from the lateral canthus up to

the lacrimal point. The samples from each eye were

placed in separate tubes containing thioglycolate broth

and incubated at 37˚C for 24 h. The bacterial isolation

and identification were performed using standard me-

thods, as described elsewhere [4].

2.3. Statistical Analysis

The chi-squared test was used to compare the studied

variables. A P value less than 0.05 was considered statis-

tically significant.

3. Results

The results of this study are summarised in Tables 1 and

2 Coagulase-negative staphylococci were the most com-

monly cultured bacteria identified on both the lid margin

and the conjunctiva sac. In the study group, approxi-

mately 3 times as many organisms were isolated from the

lid margin compared to the control group (P = 0.0223).

There was no statistically significant difference between

the groups in the total positive culture from the conjunc-

tival sac (P = 0.5409).

4. Discussion

An analysis of the bacteria present at the edge of the eye-

lids and the conjunctiva (Tables 1 and 2) demonstrated

that increased bacterial contamination levels were sub-

stantially more pronounced at the edge of the eyelids

after the ocular compression.

This finding indicates that the probable source of con-

tamination was the lid margin, specifically the mei-

bomian gland ducts. The impact of pressure on the eye-

Table 1. Characteristic changes in the lid margin bacterial

flora after preoperative ocular compression.

Lid margin

Isolated bacteria Study group

(n = 75) Control group

(n = 31)

Coagulase-negative

staphylococci 12 (16%) 2 (2.8%)

Staphylococcus aureus 2 (2.8%) 1 (3.2%)

Streptococcus viridans 2 (2.8%) 0 (0%)

Gram-positive bacilli 7 (9.3%) 0 (0%)

Total positive culture 23 (30.7%)* 3 (9.7%)

*P = 0.0223 compared with control.

Table 2. Characteristic changes in the conjunctival sac bac-

terial flora after preoperative ocular compression.

Conjunctival sac

Isolated bacteria Stu dy group

(n = 75) Control group

(n = 31)

Coagulase-negative

staphylococci 7 (9.3%) 5 (16.1%)

Staphylococcus aureus 2 (2.8%) 0 (0%)

Streptococcus viridans 2 (2.8%) 0 (0%)

Gram-posi t iv e bacilli 6 (8.5%) 0 (0%)

Total positive culture 16 (21.3%)* 5 (16.1%)

*In one cas e, 2 strains were isolated.

ball indirectly triggers an increase in the meibomian

gland secretion; multiple studies have demonstrated an

increased frequency of meibomitis in patients undergoing

cataract surgery [5,6]. Meibomitis has a bacterial origin,

which likely exp lains the contamination o f the lid margin

after the compression. In addition, there was less time for

the released secretion to move into the conjunctival sac

during the evaluated procedure, which likely explains

why less significant levels of bacterial contamination

were observed in the conjunctival sac. Although all of

the patients received a 0.5% levofloxacin ophthalmic

solution preoperatively, this administration could not

prevent contamination in the lid margin after the com-

pression, which is likely explained by the fact that the

bacteria reside deep within the meibomian glands. In

addition, the meibomian gland secretions contain a large

proportion of fat, which makes the lid margin hydropho-

bic and thus impenetrable by the 0.5% levofloxacin oph-

thalmic solution.

It is well known that the eyelid edges can negatively

impact eye wounds, which is why eyelids are often

covered with an adhesive film. Although this technique is

beneficial and has become the modern standard in

ophthalmic surgery, we believe the use of this adhesive

film could be improved. For example, the eyelids are

covered in a fatty substance; therefore, the film does not

Impact of Ocular Compression on Ocular Surface Bacterial Contaminat i o n

377

reliably adhere to the eyelid s. Moreover, the liquid filling

the conjunctive sac washes the free edge of the eyelids

and transfers bacteria from the lids to the surgical wound.

We studied the effect of ocular compression using the

modified Honan’s balloon, although the use of an eyelid

speculum may have a similar but less dramatic effect.

Presumably, the factors that contribute to the release of

meibomian gland secretions may be related to the ma-

nipulations performed during retrobulbar or peribulbar

anaesthesia. Theoretically, even eye movements during

surgery and immediately after surgery (performed while

the patient is under topical anaesthesia) could place

pressure on the meibomian glands. Improperly applying

antibiotics on the first postoperative day might also result

in negative consequences. Garcia-Arumi further reported

that the POE rate was higher following the administra-

tion of local anaesthesia compared to retrobulbar anaes-

thesia [7].

The most effective method of suppressing bacterial

surface contamination may be via the isolation of the lid

margin during surgery. We initiated this type of study

and evaluated the effects of covering the lid edges with

textile napkins impreg nated with 0.02% aqueous so lution

of chlorhex idine. The results indicated that the continued

presence of a strong antiseptic intraoperatively reduced

the POE rate [8].

5. Conclusion

Preoperative ocular compression performed with the goal

of reducing IOP was associated with the release of mei-

bomian gland secretions and bacterial contamination of

the eyelids. Thus, reliable intraoperative isolation of the

eyelids and the postoperative application of antibiotics

are required for effective POE prophylactic measures.

6. Acknowledgements

The authors thank the individuals who participate in this

study. None of the authors had financial or personal con-

flict of interest with regard to this study. This paper was

derived from a PhD thesis.

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