Re-using contact lenses and ophthalmic devices
B66
There is a remote theoretical risk, identified by the Department of Health (DH), of transmitting prion proteins, which are associated with transmissible spongiform encephalopathies (TSEs) and are implicated in Creutzfeldt-Jakob Disease (CJD) and variant CJD (vCJD), through re-useable ophthalmic devices and trial contact lenses. However, there is no evidence that this has occurred,203 and this risk has been questioned.204 The anterior eye has been designated as low risk.
B67
You should follow the advice of your local infection control team if available. If this is not available:
- You should use single patient use lenses and devices that contact the surface of the eye where practicable.
- You should not re-use a lens or device that is intended by the manufacturer for single use.
- When single use lenses and devices are not practicable, you should:
- balance the benefits that patients receive from contact lenses and ophthalmic devices against the transmission of disease
- apply appropriate disinfection procedures. These should include the use of sodium hypochlorite solution where possible, see section on Levels of decontamination.
Definitions of contact lenses
B68
You should note these definitions of contact lenses:
- trial contact lens: a lens that is used to assess fitting following which it is either disposed of by the clinician or dispensed to the patient. The majority of contact lens patients are currently fitted with single patient use lenses of various types
- special complex lens: a lens used by the clinician to assess performance of the design on the eye. This may be necessary where there is disease or abnormality of the lid, cornea or ocular surface. These lenses may be re-used.
B69
The above definitions can apply to the following categories of lenses:
- hydrogel lenses
- silicone hydrogel lenses
- hybrid lenses
- rigid lenses, including:
- corneal
- sclera
- scleral shells
- ocular prostheses.
B70
Special complex lenses may be of any type. If you use these lenses you must carry out appropriate disinfection.
Definitions of ophthalmic devices
B71
An ophthalmic device is any instrument which comes into contact with the ocular surface, including:
- tonometer
- contact pachymeter
- gonioscope
- other lens to aid diagnosis of disease.
B72
Where it is practicable, you should use single use devices, such as disposable tonometer heads or tips.
B73
Some devices are not able to withstand certain forms of disinfection. In these cases, you should use your professional judgement, bearing in mind that undetected disease may have sight- or life-threatening consequences.
B74
You must explain to the patient the risks and benefits of re-using a device.
How to disinfect equipment
B75
The following advice reduces the potential risk of iatrogenic transmission of CJD/vCJD via contact devices.
B76
You should not use alcohol wipes alone to disinfect contact devices as they are ineffective against many organisms, and may fix prion proteins to the surface of the instrument.
B77
Prion proteins adhere strongly to materials including smooth surfaces. You should ensure that the device is thoroughly cleaned to remove adhered debris as the potential for the transmission of cellular and proteinaceous debris via tonometer prisms has been demonstrated.205, 206
B78
You should not use agents or procedures capable of binding proteins to surfaces e.g. isopropyl alcohol, glutaraldehyde or autoclaving, unless you decontaminate devices first, following the process outlined in paragraphs below.
B79
You should use 1% sodium hypochlorite solution to disinfect equipment. This concentration is:
- appropriate for inactivating infectious agents such as bacteria and viruses
- less harmful to the eye than stronger concentrations, should it accidentally come into contact with it.
B80
You need the following equipment for disinfecting of contact lenses or ophthalmic devices:
- water for irrigation BP, or sterile normal saline
- cleaning solution, such as liquid soap or detergent
- sodium hypochlorite solution 1% (10,000 ppm of available chlorine).
B81
You should follow this process to disinfect contact lenses or an ophthalmic device:
| Step | ACDP TSE WG, 2011 recommendation203 | Notes |
|---|---|---|
| Timing | immediately after use | immediately disinfect the item, and if this is not possible, keep it in a container of water for irrigation BP or sterile normal saline, until it can be disinfected. |
| Do not dry | do not allow to dry | |
| Rinse | in water for irrigation BP/sterile normal saline for at least 30 sec | |
| Clean | rubbing with liquid soap or detergent | thoroughly clean the item (including by rubbing) to remove cellular debris and adherent protein |
| Disinfect | using sodium hypochlorite 1% (10,000 ppm of available chlorine) for 10 min |
disinfect it by using sodium hypochlorite |
| Rinse | in water for irrigation BP/sterile normal saline for at least 10 min with 3 changes of water/saline | thoroughly rinse off the sodium hypochlorite, which is toxic to the eye, before re-use |
| Dry | shake off excess, dry with tissue, re-use immediately or store dry | return the item to its dedicated case, if it has one |
| Further steps | if necessary, since hypochlorite is not effective against all spores or cysts | follow with conventional disinfection |
References
203 Managing CJD/vCJD risk in ophthalmology Annex L In: Department of Health. Advisory Committee on Dangerous Pathogens Transmissible Spongiform Encephalopathy (ACDP TSE) Risk Management Subgroup (2011) Guidance on prevention of CJD and vCJD [Accessed 20 Oct 2023]204 Buckley R (2010) Decontamination. Optometry in Practice 11(1), 25-29 [Accessed 20 Oct 2023]
205 For cellular debris: Lim R, Dhillon B, Kurian KM et al (2003) Retention of corneal epithelial cells following Goldmann tonometry: implications for CJD risk. British Journal of Ophthalmology 87(5), 583-586
206 For proteinaceous debris: Amin SZ, Smith L, Luthert PJ et al (2003) Minimising the risk of prion transmission by contact tonometry. British Journal of Ophthalmology 87(11), 1360-1362