Anterior blepharitis is an inflammation of the lid margin that is mainly microbial in origin and frequently drives consultations to eyecare professionals (ECPs) (Lemp et al, 2009). While guidelines from organizations such as the American Academy of Ophthalmology (Amescua et al, 2019) and the American Optometric Association (AOA, 2019) exist, the recommendations lack standardization and are not universally adopted in clinical practice.

The clinical presentation of anterior blepharitis often includes eye irritation and debris on the eyelashes, the location and appearance of which can provide clues as to the causative factor (bacterial, fungal, or parasitic) (Bernardes and Bonfioli, 2010; Kanski and Bowling, 2011). Although ECPs have access to a plethora of options for blepharitis management, only recently have lid hygiene products become available with antimicrobial properties, such as tea tree oil and hypochlorous acid (HOCl). While the mechanical action of using a lid hygiene cleanser can dislodge some of the debris (Benitez-del-Castillo, 2012), it does not address the cause of the blepharitis. Adding an antimicrobial ingredient to lid hygiene products should reduce the bioburden contributing to the eyelid inflammation and, consequently, help reduce symptoms.

HOCl is a molecule naturally produced by neutrophils during our immune system’s innate response (Chen et al, 2012). The released HOCl protects the healthy tissue against phagocytosed pathogens and reacts with lipids, proteins, and DNA to accelerate apoptosis (programmed cell death) of the damaged cell (Chen et al, 2012).

HOCl in Wound Care

Originally known as Dakin’s solution, HOCl has been used for decades as an antimicrobial agent (Wang et al, 2007) and successfully treated soldiers’ acute wounds in World War I (Najafi-Tagol, 2014). However, this solution was not chemically stable and contained impurities. It was not until the late 1990s that chemist Dr. Ron Najafi refined the technique to remove impurities and created pure HOCl for topical use. Later, studies were conducted for its potential use in eye care (Najafi-Tagol, 2014), which led to the first commercially available product.

HOCl is stable in solution at a pH between 3.5 and 5; however, when it comes in contact with organic tissue, such as a wound, it neutralizes automatically, making it safe for direct application to the skin (Wang et al, 2007; Del Rosso and Bhatia, 2018). Additionally, HOCl is void of preservatives, as it is in a solution of normal saline 0.9%, which makes it non-irritating and ideal for wound care (Wang et al, 2007).

HOCl has been successful in managing both traumatic and chronic wounds (i.e., diabetic ulcers) (Kramer et al, 2018). When compared to other products for skin antisepsis such as povidone iodine 5%, chlorhexidine gluconate 4%, and isopropyl alcohol 70%, HOCl has demonstrated equal or superior bactericidal efficacy (Anagnostopoulos et al, 2018). It is also effective against antibiotic-resistant bacteria including vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) (Wang et al, 2007).

HOCl in Eye Care

HOCl’s anti-inflammatory and antimicrobial activities are ideal for use in dry eye disease (DED) in which the core mechanism is inflammation. For instance, incomplete blinking allows for the accumulation of bacteria on the ocular surface, which can affect tear film stability and tissue integrity (Zhang X et al, 2017). This can disrupt the homeostasis of the ocular surface and initiate the inflammatory cycle inherent to the pathophysiology of DED (Baudouin et al, 2016). Reducing the microbial overgrowth present in blepharitis should help curb the signs and symptoms associated with DED.

HOCl Use in Lens Wear

Studies have shown that contact lens (CL) wearers have an altered ocular microbiota when compared to non-CL wearers (Shin et al, 2016; Zhang H et al, 2017). Indeed, their conjunctiva has a flora that is more similar to that of the skin (Boost et al, 2017). This alteration in the normal eye flora may have a causal link to eyelid infections; however, additional research is needed to establish this clearly (Shin et al, 2016). Nevertheless, CL wear is a known risk factor for conditions such as keratitis and DED (Craig et al, 2017; Nichols et al, 2013). An even more common effect of CL wear is CL discomfort (CLD). It has been noted that up to half of wearers experience CLD, and this can directly lead to CL discontinuation (Nichols et al, 2013). According to the TFOS DEWS II report, CLD is often associated with patient symptoms of dry eye (Nichols et al, 2013). Thus, managing DED efficiently improves patient comfort, health, and overall experience with CLs.

Another key property of HOCl is its selective microbicidal activity. While being highly efficient in reducing the overall bacterial load on the eyelid, it has minimal effect on the normal eye flora (Romanowski et al, 2018). This may prove to be particularly beneficial for CL wearers.

Managing Blepharitis

Several HOCl products are available commercially in spray formulation at concentrations ranging from 0.0085% to 0.2%. Products are either sprayed directly on the eyelid or applied to a cotton pad prior to lid margin rubbing. Currently, there are no studies linking the HOCl concentration and the severity of blepharitis; thus, product choice is at the ECPs’ discretion.

HOCl becomes unstable if exposed to ultraviolet light, direct sunlight, air, or extreme temperatures (< 10°C or > 25°C) (Ishihara et al, 2017), so patient education is key.

HOCl has proven to be an efficient anti-inflammatory and anti-bacterial agent. Its unique characteristics offer multiple advantages to ECPs in their choice of management options for anterior blepharitis. CLS

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