Tears help to moisten our eyes and wash away any foreign particles that may have gotten in1. Dry eyes is a condition whereby the eye is unable to maintain a healthy coating of tears, which results in certain symptoms1. There are numerous causes of dry eyes, which normally end up leading to the use of articial tears. The focus of today's topics is on preservatives used in eyedrops, namely its function, examples, and also some important things to note about them.
Preservatives in eyedrops serve to prolong the shelf life of the product by minimising contamination. However, preservatives can irritate and damage the corneal and conjunctival epithelium, particularly if it is already inflamed. In normal cases, tears quickly dilute and remove preservatives, but if tear secretion decreases, the risk of preservative toxicity increases2.
The severity of adverse effects of preservatives depends on the type of preservative used, the concentration of the preservative in the eyedrop, and also the frequency and duration of use. Examples of adverse effects are as follows, in ascending order of severity2:
- Mild irritation (burning or stinging)
- Symptoms of dry eye syndrome
- Severe conjunctivitis
- Rarely, corneal scarring
Some common examples of preservatives used in eyedrops are listed below as it is important to be able to identify them2:
- Benzalkonium chloride (Most irritant preservative)
- Sodium chlorite
- Stabilised oxychloro complex
- Sodium perborate
Here are a few important information about eyedrops and preservatives2:
- Most multi-dose eyedrops contain preservatives to reduce contamination, with the exception of certain brands, such as Hylo-Fresh/Forte
- Single-use units are preservative free
- The use of soft contact lenses are generally not recommended while using eyedrops that contain preservatives
- If eyedrops are used frequently, choose the least irritating preservative or ones that are preservative free
- Preservatives can accumulate in the eye over time, leading to prolonged irritation of the eye even after stopping the eyedrops
I hope this articles has given you some insight into preservatives used in eyedrops. If you found this information helpful, feel free to share it with your friends and families. Thank you for reading.
Created by KW
- Medline Plus. Dry Eye Syndrome [Internet]. Medline Plus [updated 2014 Nov 5; cited 2017 Mar 23]. Available from: https://medlineplus.gov/ency/article/000426.htm
- Australian Medicines Handbook [Internet]. Adelaide SA: Australian Medicines Handbook; [updated 2017; cited 2017 March 23]. Available from: https://amhonline.amh.net.au/chapters/chap-11/gen-principles-topical-eye.t#gen-principles-topical-eye.t14