Eye Drop Review Part 5: Strong Attractions to Cationorm
DRY EYE DROPS
Welcome back!
Previously, we have looked at two very popular drops targeting evaporative dry eyes. This time, we will look at a relatively new entrant in the market that also targets evaporative dry eyes.
It is called Cationorm. Honestly, I thought the name was really weird the first time I heard it, but after reading this article, you'll probably understand why it's named this way. Furthermore, how does it compare to the other drops we have looked at, specifically NovaTears (or EvoTears in Europe and Miebo in the US) and Systane Complete?
Product Information
Key Ingredients: Mineral oils, glycerol, tyloxapol, poloxamer 188, tris-hydrochloride, tromethamine, cetalkonium chloride, and purified water.
Target Patients: Suitable for a wide range of dry eye sufferers, from mild to severe, including those with symptoms caused by prolonged contact lens use or environmental conditions.
Preservative: Preservative-free, available in multi-dose bottles and single-use vials
Unlike Systane Complete and NovaTears. Cationorm is suitable for contact lens wear.
How Cationorm Works:
Similar to Systane Complete, Cationorm is a nanoemulsion where tiny oil droplets are mixed in an aqueous, or water-based solution. It's unique, however, in that the nanodroplets are positively charged. It is believed that because the surface of the eye is negatively charged, the electrostatic attraction between the positively charged oil nanodroplets and the negatively charged ocular surface manifests itself as improved spreading and retention time.
Think of it like magnets; opposite charges attract, and like charges repel.
However, I personally find this mechanism raises more questions than it answers. Like, how strong is this electrostatic force, and is it significant enough to make a difference? How are the oil droplets directly attracted to the mucin layer when there is a relatively large water layer in between? How does the nanodrop interact with other molecules and lipids in the tear film?
This has led me to do further research. From the Dry Eye Workshop, they have said the following:
"It appears that anionic [negatively charged] phospholipids have a greater ability to increase lipid layer thickness than zwitterionic [neutrally charged] compounds. A possible reason is that negatively charged phospholipids contribute to a stable interface between non-polar lipids at the surface of the hydrophilic aqueous layer. This supports a suggestion that polar phos-pholipids help to form a stable multi-molecular lipid film."
An anionic phospholipid is what Systane Complete and Systane Balance use in their formulation, and it seems that having negatively charged phospholipids is better at maintaining a stable tear film than neutrally charged phospholipids. Obviously, this doesn't translate directly to Cationorm, but as far as I know, there's no evidence to say that it performs better than Systane Complete/Systane Balance in clinical trials.
Our Verdict:
I personally prefer NovaTears and Systane Complete to Cationorm. And I prefer NovaTears over Systane Complete. But Cationorm can be used with contact lens wear, so this could be a deciding factor for you.
The reason I prefer NovaTears more is that it is the only drop that has been shown to modify the oil in the meibomian glands themselves. All other eye drops are temporary in nature and are masking the underlying problem.
A Note from the Author
P.S. Not many research evidence studies exist that compare these three drops. The closest one I can find is a recent study done in 2021 to compare EvoTears with Cationorm and Systane Balance in patients with mild dry eyes. And essentially, they didn't find much difference, in terms of tear break-up time, lipid layer thickness, etc. Evotears did relieve subjects' symptoms more, but since the study wasn't double masked, we don't know if there's bias or not. Another study found that Cationorm were more effective in reducing inflammation after a corneal wound was induced in rats, compared to Systane Balance and Optive and Vismed (Hyaluronate), but did not speed up the rate of healing. This suggests that Cationorm is better for post-surgical patients.
Thank you for taking the time to read my review. As an optometrist based in Australia, I aim to provide practical and well-researched information.
It is important to note that clinical studies around eyedrops are often funded by the company that makes them. Therefore, I encourage you to consider the findings with a discerning eye. More importantly, what works for one person might not work for another, and what doesn't work for you might work for someone else. Such is the nature of dry eye treatments.
This website is currently a work in progress, and I plan to add more visuals, including pictures and videos, and links to purchase these eyedrops in the future. Please keep in mind that product names and availability may vary in your country.
Reference:
Seqirus (Australia) Pty Ltd. (n.d.). Cationorm. Retrieved from https://www.cationorm.com.au/
Daull, P., Feraille, L., Elena, P. P., & Garrigue, J. S. (2016). Comparison of the Anti-Inflammatory Effects of Artificial Tears in a Rat Model of Corneal Scraping. Journal of ocular pharmacology and therapeutics : the official journal of the Association for Ocular Pharmacology and Therapeutics, 32(2), 109–118. https://doi.org/10.1089/jop.2015.0054
Groß, D., & Kaercher, T. (2021). Comparison of the Clinical Efficacy of Three Different Eye Drops for the Treatment of Dry Eye. EC Ophthalmology, 12(6), 32-44. Accessed from https://ecronicon.net/assets/ecop/pdf/ECOP-12-00775.pdf
Korb, D. R., Greiner, J. V., & Glonek, T. (2002). The effects of anionic and zwitterionic phospholipids on the tear film lipid layer. Advances in experimental medicine and biology, 506(Pt A), 495–499. https://doi.org/10.1007/978-1-4615-0717-8_69
Tear Film and Ocular Surface Society Dry Eye Workshop II (TFOS DEWS II) Management and Therapy Report. (2017). The Ocular Surface, 15(3), 323–352. https://doi.org/10.1016/j.jtos.2017.05.006