Editor’s note: The first part of this article appeared in November 2011 and reviewed normal human floral of the skin. This installment focuses on the ocular area.
As stated in the first part of this article, cosmetics are not expected to be sterile; however, they must be produced under Good Manufacturing Practices (GMP) and be free from microorganism concentrations and types that may cause product spoilage or adversely impact consumer health. Humans are host to an extensive assortment of microorganisms, and while the normal flora play an essential role in health, some may also become pathogenic under certain conditions, e.g., if the microorganisms gain access to deeper tissues as a result of trauma, surface breaks and wounds. The normal flora may also become pathogenic if transferred to immunocompromised persons. Therefore, preservative systems must be effective against flora transmitted from consumer handling and product application.
Like skin flora, the composition of normal eye flora is dynamic and can vary with age, environment, geographic region, exposure to antimicrobial agents, and immunological states. As knowledge of the normal ocular flora grows, the role and composition of personal care products and cosmetics may also diversify. For instance, saturated cleansing pads marketed for eyelid hygiene or cleansing must provide antibacterial efficacy against eyelid bacteria but without causing irritation; thus, while broad-spectrum protection may be warranted, perhaps preservatives may be more tailored to uniquely match the insult challenges of this specific site. Taking all this into consideration, the present article reviews not only the transient and resident microbes of ocular flora, but also considers how cosmetic products may affect and/or be impacted by them.