Following a successful pilot study, researchers at the University of Auckland are conducting a clinical trial of castor oil as a potentially safe and natural treatment for dry eye conditions.

It is estimated that dry-eye illness affects approximately 58 per cent of the population aged 50 and up in Australia.

Some risk factors for developing dry eye disease include advanced age, menopause, increased screen time, and contact lens wear. Blepharitis is the leading cause of dry eye illness, accounting for more than 80 per cent of cases. It is a chronic disease with no known cure.

"Currently, patients are left grappling with symptoms of dryness, grittiness and, in some cases, watery eyes that feel uncomfortable impacting on their quality of life and work productivity," says doctoral candidate and lead clinical investigator.

Current treatments, such as antibacterials and anti-inflammatories, are generally unsuitable for long-term use, due to significant side effects and the potential for antimicrobial resistance.

"Often patients are left feeling helpless when attempting to manage a chronic condition," the clinical investigator said. The current trial is of a product containing cold-pressed castor oil enhanced with manuka and kanuka oils applied using a rollerball attached to a small glass bottle.

"The previous pilot study, conducted by our research team, was unique in its use of castor oil in such an application on the eyelids, with the product not known to be used anywhere else in the world for treating blepharitis," said a clinical investigator.

Castor oil comes from a flowering tropical or subtropical shrub from the species Riccinus communis. It has been used therapeutically for millennia, including more recently in eye cosmetics and eye makeup removers.

In the pilot study, 26 patients with blepharitis were treated with cold-pressed castor oil over four weeks. They had measurable improvements in symptoms, such as reduced redness of the lid margin, decreased thickening of the eyelid, and a decline in bacterial profusion, as well as reduced eyelash crusting.

Building on the success of the pilot study, the research team is now engaged in a more extensive double-blinded, randomised and placebo-controlled study. They are aiming to recruit 92 participants and generate robust scientific evidence for clinicians.

The ultimate goal is to sustainably improve the quality of life for this large group of patients using a natural, safe and effective product, the principal investigator said.

"Castor oil has been proposed as a natural product that could offer a safe, effective and easy-to-use alternative to existing therapies," the principal investigator said.

"My hope is this study will produce evidence-based guidance for clinicians about offering castor oil as a possible management option for patients suffering from blepharitis, so they continue to enjoy a great quality of life, read the books they love, be productive in their work environment and enjoy other visual hobbies."