Background | In the Clinic | In the Operating Theatre
| Surgical Procedures on the Posterior Eye | Ocular Tissue Transplantation
| Action if exposure to contamination takes place | Patient Risk Groups
with classical (sporadic) CJD are predominantly in their 60s and as such
may come into contact with ophthalmologists because of cataract, glaucoma
and macular degeneration, or because of visual symptoms caused by their
condition1. Although there is no clear evidence of the transmission
of spongiform encephalopathy from one patient to another by ophthalmic
surgery other than through corneal transplantation2, it has
been accepted for many years that instruments used on patients with known
or suspected CJD undergoing any surgical procedure, should be destroyed3.
number of individuals in the UK who may develop variant CJD (vCJD), believed
to be the human form of BSE, is unknown but may yet number tens of thousands
who may be infectious before their symptoms develop. The Department of
Health (DH) has identified ophthalmology as an area of risk second only
to neurosurgery, though other forms of surgery, e.g. on the gut and tonsils,
could also lead to contamination of instruments by prions which routine
decontamination does not eradicate. Research is in progress to establish
the efficacy of current and improved methods of decontamination in removing
only certain way to avoid the as yet unquantifiable risks of ophthalmic
devices and instruments being vectors of transmissible prions would be
for them all to be disposable, though this is currently impossible without
severely compromising patient care. In 1999, the Medical Devices Agency
issued Advice Notes on contact lenses4 and on devices5
that touch the eye, though their full implementation at that time was not
feasible. The College of Optometrists and the Association of British Dispensing
Opticians have since agreed the case with the DH for a more pragmatic approach
and have published practical guidance6 which was circulated to their members
in October 2001.
are, however, situations where improved awareness and changes in clinical
practice can be implemented without compromising other standards or necessarily
increasing costs, in order to minimise the risk of transmission of prion
In the Clinic
A significant proportion of patients with classical CJD present with visual
disturbance. Key features3 which should raise suspicion are:
Unexplained visual loss in the middle-aged and elderly.
For any patient, including those being pre-operatively assessed for surgery,
the possible onset of either form of CJD should be considered. The features
of vCJD to date have not included visual symptoms until the late stages,
though it should be noted that this form of disease occurs in much younger
people (median age 29)7. Suspicion should be raised in any patient
under the age of 50 years who, in the preceding year, has experienced new
psychiatric or neurological symptoms sufficient to warrant referral to
a psychiatrist or neurologist8.
Homonymous hemianopia in the absence of evidence of space-occupying lesion
or CVA on MRI scan.
Tonometry: disposable tonometer heads9, tonometer shields10
or Tonopens are essential for the patient who is known to have or is under
suspicion of having CJD (see Table
1). One or more of these devices should be available in all departments11.
Re-usable tonometer heads: tonometer prisms should not be moved between
clinical workstations, clinics and departments, to facilitate tracing and
so that their life may be more readily determined for the purpose of regular
replacement. Current methods of hygiene are acceptable, but it should be
noted that the manufacturer Haag-Streit AG has determined12
that Goldmann tonometer prisms may be re-used 100 times following immediate
cleaning and subsequent disinfection in sodium hypochlorite solution of
(in Haag-Streit's own example, greater than) 2% for one hour at room temperature.
If this method is used, tonometer heads should then be rinsed thoroughly
in sterile saline or boiled water and wiped dry.
Soft and rigid contact lenses: ideally all contact lenses should be for
the use of one individual only. Nowadays most contact lens wearers use
disposable soft lenses. These, and some other soft and rigid lenses, can
be fitted empirically and will never need to be re-used on other wearers.
Exceptions have to be made for 'special complex diagnostic contact lenses6'
in fitting sets and it has been established that these lenses (both corneal
and scleral) may be decontaminated without damage using 20,000 ppm available
chlorine from sodium hypochlorite solution (e.g. 2% Milton Sterilising
Fluid) for 1 hour6 after which they must be thoroughly rinsed
in sterile saline (e.g. 3 full rinses in a 10ml contact lens case is adequate
to dilute residual chlorine to a safe level of 1 ppm) and then disinfected
in the normal way, e.g. dry storage or disinfectant solution storage.
It is recommended that between patients examination (diagnostic) contact
lenses (e.g. gonio, 3-mirror and fundus lenses) are wiped clean whilst
moist before the face of the lens is immersed in the disinfection fluid
normally used. At the end of each session they should be cleaned with detergent,
rinsed thoroughly in sterile saline and then wiped dry. Work on the compatibility
of such devices with sodium hypochlorite 2% solution is not yet complete.
Diagnostic contact lenses should not be moved between clinics and departments.
In the Operating Theatre
All instruments and devices marketed as being disposable must be disposed
of after single use13.
By March 2002, all personnel involved with any operation in any surgical
discipline, including Ophthalmology, and the instrument trays, must be
identifiable and traceable13.
The cleaning of surgical instruments is now recognised to be even more
important than autoclaving in removing prion protein. Instruments should
be cleaned in washer disinfectors of a modern and high standard14.
If a patient is known to be suffering from, or is at risk of either form
of CJD (see Table
1), all instruments and devices must be segregated and destroyed by
incineration after use3.
If a patient is suspected to be suffering from any form of CJD, consideration
may be given to deferring surgery in order to allow clinical signs to be
observed or for a further opinion to be sought. If surgery is deemed urgent,
then consideration should be given to the operation, if possible, being
carried out entirely with single-use instruments. If this is not possible,
at the end of the procedure:
Re-usable instruments should be placed in an impervious plastic container
with a close-fitting lid and sealed with heavy-duty tape. The box must
be labelled with the patient's identification details, the surgical procedure
for which the instruments were used and the name of the responsible person
Surgical Procedures on the posterior eye
The box must be stored indefinitely in a designated place until the results
of further investigations are known.
If the patient is confirmed as suffering from any form of CJD, the sealed
box and its contents must remain undisturbed and be incinerated.
If an alternative and confirmed diagnosis is established, the instruments
may be removed from the box by the responsible person and be sent to CSSD
for processing in the normal way. The CSSD must be informed of this decision
before the instruments are transported.
Recent evidence from studies on the eyes of patients who have died from
classical or vCJD show that prion protein is present in the retina and
optic nerve, but not elsewhere in the eye, using the methods of Western
blotting and peroxidase staining15.
Ocular Tissue Transplantation
All instruments that penetrate the optic nerve sheath, e.g. enucleation
snares or scissors, and evisceration spoons, should be traceable to individual
patients, or preferably disposed of after single use.
Some instruments used in vitreoretinal surgery are already for single use,
and efforts are continuing to develop alternatives to those that are not
For each essential non-disposable instrument that enters the vitreous cavity
or comes close to or touches the retina, e.g. membrane scissors, the patient
on whom they are used should be identifiable.
Guidelines on donor exclusion criteria and the retrieval of human ocular
tissue for transplantation and research are already available16
are regularly revised and are carefully utilised by eye banks. Currently
the only way to exclude donors known or suspected to have CJD is through
the medical and behavioural history.
Suggested information for transplant recipients that specifically mentions
remote risk of disease transmission is also available16.
Eye retrieval is now possible and recommended using disposable instruments17.
Eye Banks are advised that disposable instruments are now also available
for all stages of processing17.
During corneal transplantation, all trephines and trephine blocks should
be disposed of after single use.
Eye banks in the UK will continue to provide sclera on request, though
the proximity of the sclera to the retina and optic nerve, where prion
proteins may be present15, suggests that if alternative methods
and materials are available, and that these should be given due consideration
It is essential that records of all ocular donor tissue are kept by eye
banks; details of surgery should be recorded on the Royal College/UKT Transplant
Record Form (or similar), and returned to the UK Transplant Information
The ability to trace all recipients of ocular tissue transplants and to
monitor outcome are key components of a surgeon's responsibility. Completion
of the Royal College/UKT Follow-up Forms is strongly encouraged for at
least 5 years following corneal transplantation for penetrating and lamellar
Surgeons should, through their Hospital Manager, ensure that hospital records
of transplant recipients should be kept for at least 8 years after the
patient has died or been lost to follow-up.
Ocular tissue transplant recipients are currently not accepted as blood
Action if exposure to contamination takes place
CJD Incidents Panel (established November 2000) has already received several
reports of ophthalmic incidents since September 1999, concerning known
or suspected sporadic CJD, mostly involving cataract surgery. If a patient
undergoing ophthalmic surgery subsequently develops any form of CJD, it
is desirable that all instruments and devices involved should be traceable
and taken out of circulation, and that subsequent patients who may have
inadvertently been put at risk can be identified. For further advice in
such an event contact Dr Philippa Edwards, Department of Health, Skipton
House, 80 House Road, London, SE1 6LH, tel: 0207 - 972 5324, e-mail: mailto:email@example.com
A consultation document from the CJD Panel is accessible on www.doh.gov.uk/cjd/consultation
CJ, McIlwaine GC, Zeidler M. CJD and the Eye. II. Ophthalmic and Non-Ophthalmic
Features, Eye 2000; 14: 291-301
RN, Brown P, Heck E, Cavanagh HD. Risk of Prion Disease Transmission from
Ocular Donor Tissue Transplantation, Cornea 1999; 18: 2-11
1988 1 (Annex 1)
AN1999 (03): Single patient use of contact lenses: implications for clinical
practice. Medical Devices Agency, October 1999
AN 1999 (04): Single patient use of ophthalmic medical devices: implications
for clinical practice. Medical Devices Agency, October 1999
of Optometrists and Association of British Dispensing Opticians, September
2001: Guidance on the Re-Use of Contact Lenses and Ophthalmic Devices
RG, Ironside JW, Zeidler M et al. A New Variant of Creutzfeldt-Jakob Disease
in the UK, Lancet 1996; 347: 921-5
RG et al: Psychiatric features of new variant Creutzfeldt-Jakob Disease,
Psychiatric Bulletin 1999: 23; 264-7
Clarke International Limited, Edinburgh Way, Harlow, Essex, CM20 2TT (Fax.
Kestrel Healthcare Ltd, Network House, Basing View, Basingstoke,
RG21 4HG (Tel. 01256-307580, Fax. 01256-307590)
Desai SP, Sivakumar S, Fryers PT. Evaluation of a disposable prism for
tonometry, Eye 2001; 15: 279-282
Haag-Streit Dok. Nr. 9202 9200066 01010, 1998: Desinfektion der Haag-Streit
Kontacktgläser und Tonometermesskörper
MDA DB 2000(04): Single-use Medical Devices: Implications and consequences
HSC 2000/032 Decontamination of Medical Devices
Wadsworth JDF, Joiner S, Hill AF, et al. Tissue distribution of protease-resistant
prion protein in variant Creutzfeldt-Jakob disease using a highly sensitive
immunoblotting assay, Lancet 2001: 358; 171-80
AMG Medical Products, 48 Church Street, Shipston on Stour, Warwickshire,
CV36 4AS (Tel: 01608 662029; Fax 01608 663222).
1999/178: Variant Creutzfeldt-Jakob disease (vCJD): Minimising the risk
of transmission, NHS Executive, August 1999
Spongiform Encephalopathy Agents: Safe Working and the Prevention of Infection,
Advisory Committee on Dangerous Pathogens, 1998
AB, Buckley RJ, Painter M. CJD and the Eye, Eye 2000; 14: 259-260
S, Kaye SB, Tullo AB, Hart CA. CJD and Optometry: What are the risks? Optometry
or at-risk patients
diagnosed as having CJD or a related disorder*
patients who are potentially at risk of developing CJD or a related disorder,
recipients of hormone derived from human pituitary glands, e.g. growth
recipients of human dura mater grafts;
people with a family history of an inherited form of CJD or related disorder,
i.e. close blood line relatives (parents, brothers, sisters, children,
grandparents and grandchildren); sometimes patients may be uncertain of
the type of CJD of which their relative(s) dies; in such circumstances,
if two or more family members have been diagnosed as CJD patients, this
is a good indication that it is the inherited form of the disease.
suspected of having CJD or a related disorder* i.e. whose clinical symptoms
are suggestive of CJD but where the diagnosis has not yet been confirmed.
i.e. classical sporadic CJD, vCJD, Gerstmann-Sträussler-Scheinker
disease, fatal familial insomnia and kuru