Preservatives are added to some eye lubricants and treatments in order to prevent harmful bacteria growing inside the medicine bottle once opened
. The addition of these preservatives allows for multi-dose packaging and while these preservatives are very effective against pathogens, they were not specifically designed to be friendly to the eye
. Some of the over-the-counter (OTC) eye treatments available in your pharmacy will contain preservatives, others will make a point of clearly stating they are preservative-free, but do your customers, and your pharmacy team, always understand their significance?
Why can preservatives be an important consideration when recommending eye treatments?
In a patient with mild dry eyes, preserved drops are often well tolerated when used 4–6 times a day or less
. However, preservatives tend to consist of harsh chemicals to stop bacterial growth, which can also be harmful to the corneal and conjunctival epithelial cells
. Therefore, preservatives used in large quantities or over a prolonged period of time — months or years — can damage the delicate surface of the eye
. They can also trigger changes in the tear film causing eye dryness and patient discomfort
. A preservative that’s commonly associated with eye irritation is benzalkonium chloride and if customers have more than one eye condition for which they are using eye treatments, their potential exposure to such preservatives is increased
. In addition, preservatives in eye drops can attach themselves to contact lenses which can lead to eye damage and irritation
, potentially affecting the 4.2 million people in the UK who wear them
When to recommend preservative-free products
Preservative-free products can be a key consideration:
- When a customer’s symptoms mean that they need to use eye drops more than 6 times a day
, as preservative-free drops may help prevent exacerbation of symptoms
- For a customer regularly wearing soft or hybrid contact lenses
- If a customer has a chronic eye disease, or is on multiple preserved topical medications
- If a customer has a preservative allergy
- If a customer has ocular surface disease or inflammation
- If there is evidence of toxicity — demonstrated by persistent red eyes — as there are some preservatives which act like a detergent and can make the eyes go red
Preservative-free formulations are often available in single-dose units. However, there are now some products available that offer the benefits of multi-dose packaging
|Dry and tired eyes||Itchy and watery eyes|
|Product||Double Action Drops for dry and tired eyes — works with the eyes to help restore moisture. Always read the label.||Double Action Drops for itchy and watery eyes — designed to soothe itchy eyes due to environmental allergens such as pollen. Always read the label.|
|Contains||Boric acid, sodium chloride, hydroxypropyl, methylcellulose, sodium hyaluronate, sodium borate, WFI||Sorbitol, sodium hydroxide, carbomer, sodium chloride, WFI|
|Use||Lasts for up to three months after opening.||Lasts for up to three months after opening.|
|Contact lens suitable|
* Up to four hours.
â€ Compared to all other Optrex drops for dry eye.
â€¡ Allow an interval of 30 minutes with other drops.
 Review of Opthamology. The pros and cons of preservatives. 2015. Available at: https://www.reviewofophthalmology.com/article/the-pros-and-cons-of-preservatives (accessed December 2018)
 All Wales Medicines Strategy Group. Dry eye syndrome guidance. 2016. Available at: www.awmsg.org/docs/awmsg/medman/Dry%20Eye%20Syndrome%20Guidance.pdf (accessed December 2018)
 Pharmacy Service Negotiating Community. Opening Pandora’s box - topical medications, toxicity and compliance. 2015. Available at: https://psnc.org.uk/nottinghamshire-lpc/wp-content/uploads/sites/21/2014/07/MM-PRESERVATIVES-AND-TOXICITY-HANDOUT-v1-20150319.pdf (accessed December 2018)
 Association of British Dispensing Opticians. ACLM 2016 contact lens statistics. 2017. Available at: https://www.abdo.org.uk/news/aclm-2016-contact-lens-statistics/ (accessed December 2018)
 Pharmaceutical Journal. Dry eye disease: preservative versus preservative-free products. 2017. Available at: https://www.pharmaceutical-journal.com/20203769.article (accessed November 2018)
 NHS. Position Statement on the prescribing of Preservative Free Eye Drops. 2016. Available at: http://www.dorsetccg.nhs.uk/Downloads/aboutus/medicines-management/Other%20Guidelines/Position%20Statement%20on%20the%20prescribing%20of%20Preservative%20Free%20Eye%20Drops.pdf (accessed November 2018)