Royal College of Ophthalmologists Guidelines |
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Creutzfeldt-Jakob Disease (CJD) and Ophthalmology |
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1. Background Patients 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. The 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 prion protein. The 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. There 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 protein. 2.1 A significant proportion of patients with classical CJD present with visual disturbance. Key features3 which should raise suspicion are: 2.1.1 Unexplained visual loss in the middle-aged and elderly.2.2 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. 2.3 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. 2.4 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. 2.5 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. 2.6 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. 3.1 All instruments and devices marketed as being disposable must be disposed of after single use13. 3.2 By March 2002, all personnel involved with any operation in any surgical discipline, including Ophthalmology, and the instrument trays, must be identifiable and traceable13. 3.3 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. 3.4 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. 3.5 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: 3.5.1 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 (theatre manager).3.6 Surgical Procedures on the posterior eye 
3.6.1 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 staining15.4. Ocular Tissue Transplantation
4.1 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. 4.2 Suggested information for transplant recipients that specifically mentions remote risk of disease transmission is also available16. 4.3 Eye retrieval is now possible and recommended using disposable instruments17. 4.4 Eye Banks are advised that disposable instruments are now also available for all stages of processing17. 4.5 During corneal transplantation, all trephines and trephine blocks should be disposed of after single use. 4.6 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 by surgeons. 4.7 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 Executive. 4.8 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 keratoplasty. 4.9 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. NB: Ocular tissue transplant recipients are currently not accepted as blood donors. 5.
Action if exposure to contamination takes place The 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:claire.mills@doh.gsi.gov.uk NB: A consultation document from the CJD Panel is accessible on www.doh.gov.uk/cjd/consultation References: 1 Lueck CJ, McIlwaine GC, Zeidler M. CJD and the Eye. II. Ophthalmic and Non-Ophthalmic Features, Eye 2000; 14: 291-301 2 Hogan RN, Brown P, Heck E, Cavanagh HD. Risk of Prion Disease Transmission from Ocular Donor Tissue Transplantation, Cornea 1999; 18: 2-11 3 HSC 1988 1 (Annex 1) 4 MDA AN1999 (03): Single patient use of contact lenses: implications for clinical practice. Medical Devices Agency, October 1999 5 MDA AN 1999 (04): Single patient use of ophthalmic medical devices: implications for clinical practice. Medical Devices Agency, October 1999 6 College of Optometrists and Association of British Dispensing Opticians, September 2001: Guidance on the Re-Use of Contact Lenses and Ophthalmic Devices 7 Will RG, Ironside JW, Zeidler M et al. A New Variant of Creutzfeldt-Jakob Disease in the UK, Lancet 1996; 347: 921-5 8 Will RG et al: Psychiatric features of new variant Creutzfeldt-Jakob Disease, Psychiatric Bulletin 1999: 23; 264-7 9 Clement Clarke International Limited, Edinburgh Way, Harlow, Essex, CM20 2TT (Fax. 01279-635232) 10.
Kestrel Healthcare Ltd, Network House, Basing View, Basingstoke,
11. Desai SP, Sivakumar S, Fryers PT. Evaluation of a disposable prism for tonometry, Eye 2001; 15: 279-282 12. Haag-Streit Dok. Nr. 9202 9200066 01010, 1998: Desinfektion der Haag-Streit Kontacktgläser und Tonometermesskörper 13. MDA DB 2000(04): Single-use Medical Devices: Implications and consequences of reuse 14. HSC 2000/032 Decontamination of Medical Devices 15. 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 16. www.rcophth.ac.uk 17. AMG Medical Products, 48 Church Street, Shipston on Stour, Warwickshire, CV36 4AS (Tel: 01608 662029; Fax 01608 663222). Further
Reading: HSC 1999/178: Variant Creutzfeldt-Jakob disease (vCJD): Minimising the risk of transmission, NHS Executive, August 1999 Transmissible Spongiform Encephalopathy Agents: Safe Working and the Prevention of Infection, Advisory Committee on Dangerous Pathogens, 1998 Tullo AB, Buckley RJ, Painter M. CJD and the Eye, Eye 2000; 14: 259-260 Anderson S, Kaye SB, Tullo AB, Hart CA. CJD and Optometry: What are the risks? Optometry Today 2001
January, 2002 |
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