Many over-the-counter products for dry eye disease contain preservatives. These can help make products last longer once opened and mean products can be available in multi-dose packaging.
However, preservatives can worsen symptoms for some patients with dry eye disease, particularly if they are applying treatments more than six times throughout the day. This is because some commonly used preservatives, including benzalkonium chloride, can disrupt the tear film further.
- Advise patients using eye drops more than six times throughout the day to use a preservative-free formulation. This may help to prevent exacerbation of symptoms;
- If a patient presents with symptoms of dry eye disease that are worse in one eye, it could be because they are using preservative-containing drops more often in that eye. If a patient presents with these symptoms, enquire about what treatment they are currently using and how often in each eye. If they are using a multi-dose formulation containing a preservative, advise that they try a single-dose or preservative-free formulation.
Preservative-free formulations are often available in single-dose units. However, there are some products available in multi-dose packaging that contain ‘vanishing preservatives’, such as sodium perborate or sodium chlorite. These may not be tolerated well in some patients.
Example: Advising a patient about preservatives
Mr Black approaches the pharmacy counter. You recommended some artificial tears for him approximately a fortnight ago.
Pharmacy technician: Hi, Mr Black. How are you getting on with the drops?
Mr Black: Hi there. Well, to be honest, they really helped for the first few days. Really helped to make my eyes feel more comfortable, you know. I was using them about once an hour all day.
Pharmacy technician: You said for the first few days?
Mr Black: Yes. Over the past few days, they have stopped helping and my eyes feel a bit sore and irritated.
Pharmacy technician: I’m sorry to hear that. It is possible you are having a slight reaction to the preservatives in these drops. It can affect some people, especially if they are using the drops very often to help relieve symptoms, as you have been.
Mr Black: Oh dear. Is there something I can use instead?
Pharmacy technician: Yes, there is something else we can try. These are single-unit drops, so you use the whole dose at once. They do not contain preservatives, so you shouldn’t have the same reaction. These drops are also a little thicker, so you should not need to apply them so regularly. If you are still having problems, or your symptoms get worse, please make an appointment with your optician.
Mr Black: Thank you for the recommendation. I will let you know how I get on with these new drops.