The multifactorial pathogenesis and interrelationship of
blepharitis,
meibomian gland dysfunction and
dry eye disease poses challenges to any therapeutic approach. Current treatments are mostly palliative, with success limited by perceived inefficacy and poor patient compliance.
Castor oil, a natural derivative of the Ricinus communis plant, is widely used as an
emollient in
cosmetics and
personal care products, drug delivery systems and
wound dressings.
Castor oil is deemed safe and tolerable, with strong anti-microbial, anti-inflammatory, anti-nociceptive,
analgesic,
antioxidant, wound healing and vaso-constrictive properties. Its main constituent,
ricinoleic acid, has a bipolar molecular structure that promotes the formation of
esters,
amides and
polymers. These can supplement deficient physiological tear film
lipids, enabling enhanced
lipid spreading characteristics and reducing aqueous tear evaporation. Studies reveal that
castor oil applied topically to the ocular surface has a prolonged residence time, facilitating increased tear film
lipid layer thickness, stability, improved ocular surface staining and symptoms. This review summarises the properties, current uses of, and therapeutic potential of
castor oil in managing ocular surface disease. The biochemical, medicinal actions of
castor oil are explored from the perspective of ocular surface pathology, and include microbial and demodectic over-colonisation, inflammatory and oxidative processes, as well as clinical signs and symptoms of dryness and discomfort.