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.
Randomized trial of topical periocular castor oil treatment for blepharitis
Introduction
Blepharitis is a commonly encountered ophthalmic condition in clinical practice, characterised by chronic inflammation of the eyelid tissues and ocular surface. The condition is recognized to have adverse impacts on ocular comfort, visual function, and quality of life. Blepharitis can involve both the anterior and posterior eyelid lamellae, and the inflammatory processes can spread to the periocular skin, eyelashes, eyelid margin, and Meibomian glands. This is frequently associated with symptoms of ocular surface irritation and dry eye disease, and irreversible sight-threatening corneal damage can occur in the most severe cases.
As a complex multifactorial condition, the pathophysiology of blepharitis remains yet to be fully understood. Abnormally high levels of bacterial load are commonly observed in the eyelid tissues of patients with blepharitis and may predispose towards an overactivation of host immune responses and trigger hypersensitivity reactions. Moreover, lipolytic exoenzymes released by colonising bacterial species can further augment pre-existing inflammatory processes, and lead to tear film destabilisation via the breakdown of lipid layer constituents. In recent years, ocular infestation with Demodex mites has also been increasingly acknowledged to be a significant risk factor for the development of blepharitis.
Management strategies for blepharitis typically involve the administration of topical antimicrobial and anti-inflammatory agents during acute flares, in combination with long term adherence to eyelid hygiene regimens and warm compress therapy for baseline symptomatic control. Nevertheless, the use of antimicrobial and anti-inflammatory agents is associated with concerns surrounding microbial resistance and side effect profiles, while patient adherence to palliative treatments can be adversely impacted by perceptions of therapeutic inefficacy and inconvenience. These issues highlight the ongoing need for the development of novel intervention strategies, which might target the underlying causes of bacterial colonisation, ocular demodicosis, and associated over-activation of host immune and inflammatory responses.
Castor oil, a derivative of the Euphorbiaceae plants, is well known for its anti-inflammatory, antimicrobial, and emollient properties. Emulsion eye drops of castor oil formulations have been previously demonstrated to effect short-term improvements in tear film stability and lipid layer thickness, but the potential efficacy of topical castor oil application to the periocular skin for the management of blepharitis has not yet been investigated. The current four-week, investigator-masked, randomized trial therefore sought to evaluate the effects, on ocular surface and tear film parameters, of topical castor oil application to the eyelids in patients with blepharitis.
Purpose
To evaluate the effects of topical castor oil application to the eyelids on ocular surface and tear film parameters in patients with blepharitis.
Subjects
This four-week, investigator-masked, randomized, paired eye trial conformed to the tenets of the Declaration of Helsinki, was approved by the University of Auckland Human Participants Ethics Committee (UAHPEC 020783), and was registered as a clinical trial (ACTRN12618000856213). Participants were recruited through open advertisement at a single university centre, as well as via referrals from local optometric practices. Eligibility required participants to be 18 years or older,
Methods
Twenty-six participants (14 females, 12 males; mean ± SD age, 38 ± 21 years) were enrolled in a prospective, investigator-masked, randomized, paired-eye trial. All eyes in the treatment and control groups demonstrated clinical signs of anterior blepharitis and Meibomian gland dysfunction at baseline. Corneal infiltrates were not present in any of the eyes in either group. A 100% cold pressed castor oil formulation was applied to the eyelids of one eye (randomized), twice daily for 4 weeks. Ocular surface characteristics, symptoms, and tear film parameters were assessed at baseline and day 28.
Results
Baseline measurements did not differ between treated and control eyes (all p > 0.05). A significant reduction in OSDI symptomology score was observed following the four-week treatment period (p = 0.001). Clinical improvements in eyelid margin thickening, telangiectasia, eyelash matting, madarosis, cylindrical dandruff, and lid wiper epitheliopathy were limited to treated eyes (all p < 0.01), while greater decreases in staphylococcal and seborrheic eyelash crusting were observed in treated than control eyes (both p < 0.05). No adverse events were reported during the treatment period.
Conclusions
In conclusion, the results of the study demonstrate that clinical improvements in ocular surface signs and symptoms were visible in patients with blepharitis, following a four-week treatment period with twice daily topical application of the castor oil formulation to the eyelids. A significant decrease in the OSDI and DEQ-5 symptomology scores was reported on day 28, and greater reductions in eyelid margin thickening, telangiectasia, eyelash matting, madarosis, cylindrical dandruff, staphylococcal and seborrheic eyelash crusting, and lid wiper epitheliopathy.
The favourable therapeutic profile would suggest that topical castor oil application effected significant improvements in ocular surface signs and symptoms in patients with blepharitis and demonstrates promise as a potential treatment for blepharitis and support the conduct of further efficacy trials with longer follow up.
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