Sterilisation vs disinfection: what reusable ophthalmic instruments really need
Real-world dry eye management from Sarah Farrant
In clinical practice, the words cleaning, disinfection and sterilisation are often used as if they mean the same thing.They do not.For optometrists and eye care professionals using reusable ophthalmic instruments, the difference matters. It affects how instruments are cleaned, how they are stored, how they are reused and when they should be replaced.It also helps avoid one of the most common problems in practice: reaching for a product because it sounds suitable, rather than because it is appropriate for the instrument, the procedure and the level of patient contact involved.
Cleaning comes first
Before an instrument can be disinfected or sterilised, it must be clean.Cleaning is the process of removing organic or inorganic debris. In practical terms, this may include visible residue, tear film, proteinaceous material or other contamination left after use.The College of Optometrists is clear that items must be cleaned before progressing to disinfection or sterilisation. That is an important point because disinfection is not a shortcut around cleaning. If debris remains on an instrument, the disinfection process may not be effective in the way the clinician expects.
What is disinfection?
Disinfection reduces viable microorganisms to a safer level. It may be carried out using heat or an appropriate chemical disinfectant, depending on the item and the guidance being followed.In optometric practice, many reusable items require cleaning or disinfection rather than sterilisation.The correct approach depends on how the instrument is used. A trial frame, a chin rest and an instrument that comes into contact with the ocular surface do not all carry the same risk profile.
What is sterilisation?
Sterilisation means killing or removing all microorganisms, including spores.
That sounds like the highest and safest level, but it is not automatically required for every item. The College of Optometrists notes that sterilisation is not normally required in optometric practice. It is required where equipment is introduced into a sterile body area or comes into contact with a break in the skin or mucous membrane.
This is why the question should not be:
“How do I sterilise this?”
It should be:
“What level of decontamination is appropriate for this instrument and this procedure?”
Why wording can be misleading
One of the difficulties in practice is that many everyday products use language such as “sterilising”, “antibacterial” or “medical grade”.
That does not necessarily mean the product is suitable for a reusable ophthalmic instrument.
That distinction matters.
A product may be marketed as a sterilising fluid in a domestic or baby-feeding context, but that does not mean it is suitable for every clinical instrument or material.
Can Milton be used on reusable ophthalmic instruments?
Milton comes up often because many people are familiar with it and because it is described as a disinfecting product on the College of Optometrists. This must never be used on metal as the product’s own guidance stipulates.
What about alcohol wipes or alcohol-based sterilisers?
Alcohol-based products are another common source of confusion.
Alcohol wipes may be suitable for some hard surfaces, such as chin rests, but the College of Optometrists states that 70% isopropyl alcohol is not suitable for medical devices that come into contact with the surface of the eye.
The College also advises that alcohol wipes alone should not be used to disinfect contact devices because they are ineffective against many organisms and may fix prion proteins to the surface of the instrument.
So, although alcohol products have a place in clinical hygiene, they should not be treated as an all-purpose answer for reusable ophthalmic instruments.
n particular, they should not be relied on for instruments that touch the ocular surface unless the manufacturer’s instructions and professional guidance specifically support that use.
How often should reusable instruments be disinfected?
Reusable instruments should be cleaned and disinfected between uses, according to the manufacturer’s instructions, professional guidance and the practice’s infection control policy.
Items that come into contact with the ocular surface, mucous membranes or bodily fluids need particular care because the risk profile is different from non-contact surfaces.
Practices should also have a clear system for storage after disinfection. A reusable instrument that has been correctly cleaned, disinfected and stored may remain suitable for use according to the practice’s infection control process. However, if there is any doubt about storage, handling, contamination or whether the item has remained clean, it should be cleaned and disinfected again before use.
There is not one universal time limit that applies to every reusable instrument. The safest answer is to follow manufacturer instructions, professional guidance and local infection control policy.
What should practices avoid?
A good practical rule is to avoid assumptions.
- Do not assume a product is suitable because it says “sterilising”.
- Do not assume alcohol wipes are suitable because they are widely used on surfaces.
- Do not assume stronger chemicals are automatically safer.
- Do not skip cleaning before disinfection.
- Do not reuse anything marked as single use.
- Do not use a method that conflicts with manufacturer instructions.
- Do not use a method that conflicts with manufacturer instructions.
The College of Optometrists specifically says practitioners should not reuse a lens or device that is intended by the manufacturer for single use.
Reusable does not mean use indefinitely
Reusable instruments can offer practical value in clinical practice. They can support consistency, reduce repeat purchasing and help clinicians work with familiar tools.
However, reusable does not mean indefinite.
Instruments should be inspected regularly and replaced when they reach the end of their recommended working life, or sooner if they become damaged, worn, corroded, difficult to clean or no longer perform as expected.
Many SOS reusable instruments are designed for a practical working life of around 3-6 months, depending on usage, cleaning process, handling and storage.
The practical principle
For reusable ophthalmic instruments, the practical principle is simple:
Clean first. Disinfect appropriately. Sterilise only when required. Replace when needed.
The correct process depends on the instrument, the procedure, manufacturer guidance and the practice’s own infection control policy.Reusable instruments can be a valuable part of everyday clinical practice, but only when they are used, cleaned, stored and replaced responsibly.
Need reusable instruments for clinical procedures?
SOS supplies reusable ophthalmic instruments selected around real clinical procedures, including dry eye, ocular surface management, meibomian gland expression and acute eye care.