Comparison of Conjunctival Antimicrobial Activity and Patient Comfort Between Topical Hypochlorous Acid (Avenova) and Betadine

About two percent of the population have an iodine allergy 1. A percentage of this population will also have a reaction to iodine-containing agents, including povidone iodine (PI) (Betadine®), which is the current standard of care for anti-septic preparation for conjunctival procedures. Despite being known to have a toxic effect on the cornea 2 and causing allergic reactions in some individuals, povidone Iodine (PI) (Betadine®) is still the most commonly used antiseptic agent for surgical scrub. Currently, there are no equivalent alternative prep agents available, although chlorhexidine has occasionally served as an alternative to povidone iodine (PI) (Betadine®) with variable results 2. Some studies have reported significantly less pain in patients prepped with chlorhexidine compared to povidone iodine (PI) (Betadine®) 2, and other studies have demonstrated that chlorhexidine has equal efficacy to povidone iodine (PI)(Betadine®) in decreasing the colony forming units of microbes both in vitro and in vivo 3. Although there have been no known reported allergies to chlorhexidine, it is known to be toxic to the cornea (leading to severe keratitis) and has proven to be less effective against methicillin-resistant Staphylococcus aureus(MRSA) 4.

The use of 0.01% hypochlorous acid (HOCl) in saline solution as an antiseptic agent has been gaining popularity as a possible alternative to povidone iodine (PI) (Betadine®). Hypochlorous acid (HOCl) is produced in vivo by neutrophils and causes oxidation of microbial nucleotides and inactivation of microbial enzymes, leading to cell death. Hypochlorous acid (HOCl) has a faster optimal kill-time for flora common to the eye 4, and has proven to be non-cytotoxic and well tolerated for continuous use 4,5,6. In vitro studies of 0.01% hypochlorous acid (HOCl) were found to have equal or more efficacious antiseptic properties compared with povidone iodine (PI) (Betadine®) and other potential antiseptic agents including chlorohexidine and isopropyl alcohol 4.

Currently, two concentrations of HOCl are available for commercial use: AvenovaTM with Neutrox™ (0.01% HOCl) and an over the counter product (0.02% HOCl). Both concentrations are used to treat blepharitis. Debabov et al5 presented toxicity data concluding that 0.01% hypochlorous acid (HOCl) (Avenova™ with Neutrox™) proved to be non-cytotoxic in comparison to the 0.02% hypochlorous acid (HOCl) product which was cytotoxic thus supporting the potential benefit of HOCl.

Stroman et al6 2017 concludes that hypochlorous acid (HOCl)in saline solution reduced bacterial colony load significantly without altering the variation of remaining bacterial species. Additionally, hypochlorous acid (HOCl) has been shown to reduce the population of bacterial and fungal species common to the lids and lashes by ≥ 99.9% 7. Despite the use of hypochlorous acid (HOCl) as a topical antiseptic on the eyelid, there have been no reports of its use as an antiseptic agent for conjunctival procedures. Many studies have confirmed that flora of the eyelid and eyelash only differ in their concentrations 8. Since hypochlorous acid (HOCl) has been found to be effective in reducing colony forming units and since the flora species of the conjunctiva, eyelid and eyelashes are equivalent, we propose that hypochlorous acid (HOCl) may serve as an alternative to povidone iodine (PI) (Betadine®) as a conjunctival procedure prep agent. Considering there were no reported negative side effects of hypochlorous acid (HOCl) contact with the eye, hypochlorous acid (HOCl) may prove to be a non-inferior alternative to povidone iodine (PI) (Betadine®). This may result in lower irritation and toxicity compared to povidone iodine (PI) (Betadine®)