Hypochlorous acid (HOCl) is a powerful, broad-spectrum disinfectant used widely in hygiene and cosmetic products for skin, wound, and surface sanitation. Due to its efficacy, many people use HOCl-based products for ocular hygiene, raising questions about its safety near the delicate eye surface. This article explores the science behind hypochlorous acid and clarifies its role as a safe and effective option for eye care when used correctly.
Understanding Hypochlorous Acid
Hypochlorous acid (HOCl) is a weak acid and a potent oxidizing agent. It is naturally produced by white blood cells (neutrophils) as a primary defense mechanism against invading pathogens like bacteria, viruses, and fungi.
For commercial use, HOCl is manufactured through the electrolysis of a saline solution, creating a stable liquid. This natural origin makes it an appealing alternative to harsher chemical disinfectants. HOCl’s antimicrobial strength is maximized when the solution’s pH is between 3 and 6.
Ocular Safety Profile
When formulated specifically for ocular use, hypochlorous acid is safe for application to the eyelids and lashes. Its safety profile depends entirely on the product’s concentration and pH level.
Ophthalmic-grade solutions are manufactured at very low concentrations (typically 0.01% to 0.02%), making them non-toxic to human cells. These specialized products are pH-neutral, balanced to match the eye’s natural tear film pH (7.0 to 7.3). Maintaining this neutral pH prevents irritation or stinging.
This careful formulation ensures the product is non-cytotoxic—it does not damage the delicate cells of the ocular surface—and is non-sensitizing for long-term daily use. Industrial-grade HOCl formulations are not suitable for use near the eyes.
How HOCl Works in Eye Care
The effectiveness of hypochlorous acid in eye care relies on its dual mechanism: targeting microbial overgrowth and inflammation. As a powerful antimicrobial agent, HOCl rapidly neutralizes pathogens by disrupting their cell walls and oxidizing necessary proteins.
This action is effective against common eyelid bacteria, such as Staphylococcus species, which contribute to eye surface diseases. HOCl can reduce the bacterial load on the eyelids and lashes by over 90% within minutes. Importantly, it achieves this without significantly disrupting the natural ocular microbiome, unlike some antibiotics.
HOCl also possesses anti-inflammatory capabilities. It neutralizes toxins released by bacteria and modulates the body’s inflammatory response, helping to soothe the chronic irritation and redness associated with eye surface conditions.
Practical Application and Usage Guidelines
Eye care professionals commonly recommend hypochlorous acid as a foundational component of eyelid hygiene, especially for managing chronic conditions. It is frequently used to treat blepharitis (eyelid inflammation) and meibomian gland dysfunction (MGD), a condition affecting the oil-producing glands. Regular use helps reduce the bacterial biofilm that often triggers these chronic issues.
HOCl is typically available as a sterile spray or saturated wipe. Users are instructed to spray the solution directly onto closed eyelids or apply it with a cotton pad, gently wiping the eyelid margins and lashes. The cleansing action is rapid, and rinsing is unnecessary. Always use commercially prepared, ophthalmic-grade HOCl products to ensure the correct concentration, purity, and pH balance for the delicate eye area.