Audit of decontamination procedures for specialist ophthalmic equipment

Journal of Hospital Infection (1995) 29, 297-300

SHORT

Audit

REPORTS

of decontamination ophthalmic C. R. Dart,

Department

procedures equipment

S. V. Goddard

for specialist

and R. P. D. Cooke

of Medical Microbiology and Infection Control, Hospital, Eastbourne, East Sussex, UK Accepted for publication

25 January

District

General

1995

Summary:

A survey of ophthalmic decontamination protocols in eight district hospitals was undertaken. Procedures differed widely. A literature search revealed only four publications on the subject, all of which dealt with tonometer head disinfection only. After discussion with several manufacturers, whose advice was restricted largely to acrylic lens disinfection and which varied considerably, a local policy for ophthalmic decontamination was established. Nationally agreed disinfection guidelines for high risk ophthalmic instruments are needed. Keywords:

Eye; disinfection;

tonometer;

acrylic

lens

Introduction

Specialist ophthalmic instruments are expensive, complex in design and prone to damage either from mishandling or the use of inappropriate disinfectants. If they are inadequately decontaminated, nosocomial outHowever, recently published disinfection guidance breaks may result.’ refers only to tonometer heads.2 The purpose of this report is to compare current decontamination procedures in a number of ophthalmic departments and to provide recommendations for future practice. Methods

A questionnaire was sent to eight departments of ophthalmology based in district hospitals (three teaching and five general) throughout England. Decontamination protocols for tonometer heads, ‘A’ scan probes, slit lamps, forceps and acrylic lenses were requested specifically. A 12 year Medline Correspondence Kings

Drive,

to: C. R. Dart,

Eastbourne

0195%6701/95/040297+04

BN21

Department 2UD,

of Medical East Sussex, UK.

$08.00/O

Microbiology,

District

General

0 1995 The Hospital

297

Hospital,

Infectron

Society

C. R. Dart et al.

298 Table

I. Analysis

of questionnaire

responses on hospital

ophthalmic

decontamination

Hospital type

Tonometer head

‘A’ scan probe

Acrylic

lenses

Slit lamp

DGH

Alcohol

wipe

Alcohol

wipe

Alcohol

wipe

DGH*

3% H,O, for 5 min 3% H,Oz

Alcohol

wipe

Alcohol

wipe

DGH*

Hypochlorite

Hypochlorite or alcohol

Alcohol

wipe

DGH*

0.02% chlorhexidine acetate Hypochlorite Hypochlorite 1000 ppm for 5 min ‘Pantasept’ Hypochlorite

Alcohol

3% HzOl(‘Hibiscrub’ if anti-reflective coating) Alcohol wipe (hypochlorite if soiled) 0.02% chlorhexidine acetate Hypochlorite Hypochlorite 1000 ppm for 5 min ‘Pantasept’ Alcohol or hypochlorite

DGH* TH

TH* TH*

wipe

Hypochlorite Hypochlorite 1000 ppm for 5 min ‘Pantasept’ Not stated

procedures

Forceps

0.02% chlorhexidine acetate Soap and water Hypochlorite 1000 ppm for 5 min ‘Pantasept’ Hypochlorite

Alcohol wipe or autoclave Autoclave

Hypochlorite or autoclave Autoclave

Autoclave Autoclave

‘Pantasept’ Autoclave

* Hospital did not state concentration of disinfectant, duration of disinfection or both. DGH, District General Hospital; TH, Teaching Hospital; HzOz, Hydrogen peroxide. ‘Hibiscrub’=chlorhexidine gluconate 4% (ICI, Macclesfield, UK); ppm, parts per million.

literature search on ophthalmic instrument disinfection was performed also. manufacturers were asked to submit their own reIn addition, commendations for the decontamination of their ophthalmic instruments. Results

All eight questionnaires were returned. Hospital decontamination procedures differed widely (Table I). Four types of disinfectants were used of which two, ‘Pantasept’ (an aldehyde solution) and 0.02% chlorhexidine acetate, are no longer commercially available in the UK. The literature search revealed only four publications on the subject all of which dealt with tonometer head disinfection only.3-6. Manufacturers, contacted through their UK suppliers, gave differing disinfection advice for acrylic lenses: 1. Ocular Instruments, Washington, US: ‘Glutaraldehyde (2% aqueous solution) for 10-20 min depending on lens type, or ethylene oxide sterilization’. 2. Nikon Tokyo, Japan: ‘Disinfect in pure alcohol and allow to air dry. For further sterilization, place the lens in dry heat at 150°C for 2-3 h’. 3. Goldmann, Kuniz, Switzerland: Use ‘an aqueous solution of disinfectant which does not affect organic glass or metal. Immerse for 5-10 min, on no account longer than 2 h’.

Audit

of decontamination

procedures

299

The only other advice came from Goldmann which commented on ‘A’ scan probe disinfection, recommending an alcohol wipe. Manufacturer guidance on the decontamination of other types of ophthalmic instruments was not forthcoming. Discussion

The eye is particularly susceptible to infection with Gram-negative bacilli, adenoviruses, Herpes simplex and fungi* all of which may be transferred by contaminated ophthalmic instruments. Transmission of HIV and hepatitis B virus is also of concern though no cases of infection have been reported by this route. Tonometer heads used for measuring intraocular pressure, ‘A’ scan probes used for determining the strength of lens implants and acrylic lenses, used for laser treatments, all come into direct contact with the cornea and so pose a high risk of cross-infection. Conversely, slit lamps and forceps are low risk items. Apart from tonometer heads, our literature search revealed no publications on how to disinfect high risk ophthalmic equipment. Ophthalmic outpatient departments are therefore placed in a particularly difficult position since high risk equipment is commonly used for the diagnosis and treatment of a wide variety of eye conditions. Because the contact element is made of a heat-labile plastic polymer, tonometer heads and acrylic lenses cannot be autoclaved unlike materials made of glass. Views on tonometer head disinfection vary. Nagington et al. compared three methods of disinfection and concluded that sodium hypochlorite at 500 ppm available chlorine destroyedH. simplex, adenovirus and enterovirus within 10 min exposure.3 However, Pepose et al. considered that alcohol wipe and air dry was best for HIV.4 Lingel and Coffey found that disinfection with sodium hypochlorite resulted in a distorted ‘dulling pattern image’ whilst alcohol rendered tonometer tips unusable in less than five days. They suggested that soaking in 3% hydrogen peroxide (H,O,) for S-10 min resulted in adequate disinfection with only minimal damage to the head.’ Disposable latex covers have been suggested as an alternative to chemical disinfection.6 Discussion with manufacturers also revealed a variety of disinfection strategies particularly for acrylic lenses. Glutaraldehyde is a toxic and irritant substance the use of which must be strictly controlled under the Control of Substances Hazardous to Health (COSHH) Regulations.7 Furthermore, an alternative to glutaraldehyde, ‘Sporicidin’ (2% glutaraldehyde, 7% phenol, 1.2% phenate), has been banned recently by the US government for not meeting ‘sterilization criteria’ (personal communication, Keeler Ltd, UK). Alcohol is flammable and must also be closely controlled under COSHH. The damage caused by H,OZ to lenses is only a risk with long-term disinfection. In practice, lenses are more frequently replaced due to breakage or scratching rather than damage caused by disinfectants

C. R. Dart et al.

300 Table

II

Local recommendations fey decontamination of ophthalmic instruments Risk assessment

Recommended

Hieh

risk

‘A’ scan probe

High

risk

Acrylic

High

risk

Slit lamp

Low

risk

Forceps

Low

risk

Soak in 3% H?O? for 10 min. Rinse in sterile water and dry with -a paper tissue Wipe with 70% isopropyl alcohol swab and allow to air dry. Rinse in sterile water and dry with a paper tissue Soak the cornea1 contact element in 3% HZ02 for 10 min. Rinse in sterile water and dry with a paper tissue. Wipe the end handled by the operator with 70% isopropyl alcohol swab to remove fingerprints Wipe with 70% isopropyl alcohol at start and finish of each session and after an ‘infected’ patient. Replace chin paper after each patient Autoclave

Instrument Tonometer

heads

lenses

decontamination

method

(personal communication, Coherant UK Ltd). Hence HzOz is a practical ‘A’ scan probes cannot be immersed option for acrylic lens disinfection. because of the electrical nature of the instrument so disinfection with a 70% isopropyl alcohol wipe is recommended. Since there is a lack of publications on this complex subject, it is not surprising that hospital protocols for decontaminating ophthalmic instruments differ widely. As a result of this study we have prepared a local decontamination policy (Table II). However, nationally agreed guidelines for the disinfection of high risk ophthalmic instruments need to be established.

We thank Mr D. G. Garlick

and Senior

Sister M. Tutt

for their comments

on the manuscript.

References 1.

2. 3. 4. 5. 6. 7.

Stephens JL, Peacock JE. Uncommon infections: eye and central nervous system. In: RP Wenzel, Ed. Prevention and Control of Nosocomial Infections, 2nd edn. Baltimore: Williams and Wilkins 1993; 747-757. Ayliffe GAJ, Lowbury EJL, Williams JD, Geddes AM. Control of Hospital Infection: A Practical Handbook, 3rd edn. London: Chapman and Hall Medical 1992; 100. Nagington J, Sutehall GM, Whipp P. Tonometer disinfection and viruses. Br J Ophthalmol 1983; 67: 674-676. Pepose JS, Linette G, Lee SF, MacRee S. Disinfection of Goldmann tonometer against Human Immunodeficiency Virus Type 1. Arch Ophthalmol 1989; 107: 983-985. Lingel NJ, Coffey B. Effects of disinfecting solutions recommended by the Centers for Disease Control on Goldmann tonometer biprisms. J Am Optom Assoc 1992; 63: 43-48. Hodkin MK, Pavilack MA, Musch DC. Pneumotonometry using sterile single-use tonometry covers. Ophthalmology 1992; 99: 688-695. Health and Safety Executive. Control of Substances Hazardous to Health. Approved Code of Practice. London: HMSO 1988.