Castor oil may have potential as a natural treatment for dry eye disease

Medical News Today Article By Erika Watts on February 8, 2024 — Fact checked by Hilary Guite, FFPH, MRCGP

Dry eye disease is a common condition that can cause inflammation in the eyes. According to the American Academy of Ophthalmology (AAO), it affects approximately 20 million people in the U.S.

While there are some treatments available for dry eye disease, researchers from the University of Auckland were curious if a natural remedy could be effective. They conducted a pilot study where participants applied castor oil to their eyelids, which proved beneficial for the participants.

The researchers are conducting another study to see if they can enhance those benefits further by mixing castor oil with mānuka and kanuka oils.

Further information about the current trial is available via the University of Auckland.

 

What causes dry eye disease?

 

The National Institutes of Health (NIH) says that dry eye disease can occur for a number of reasons, including disease, environmental factors, and allergies.

A disease called is a common culprit as it causes inflammation that leads to a thickening of the and flaking and crusting of the eyelids. This contributes to developing dry eyes.

Some signs and symptoms of dry eye disease include:

• burning or stinging in the eyes
• watery or teary eyes
• sensitivity to light
• a feeling of grittiness in the eyes

The disease is more common in people ages 50 and older, particularly in women. Women undergoing menopause are more at risk for dry eye disease since the hormone changes can lead to changes in the tear film of the eyes.

Some treatments available for dry eye disease include over-the-counter remedies such as artificial tears and nighttime lubricants. Additionally, research has shown that some people may improve the quality of their tears but not the quantity by taking vitamin A. There may be a role for omega-3 supplements, particularly in those with low dietary intake, but evidence from a systematic review concluded that the results of trials were inconsistent.

Doctors may prescribe eye drops such as cyclosporine (Restasis) or lifitegrast (Xiidra), which have an anti-inflammatory effect.

 

The 4-week trial

 

According to the National Institutes of Health, castor oil can enhance the “smoothness and softening” of the skin and can also promote “an increase in healthy pores and skin tissue through moisturizing, hydrating, and cleansing.”

With those benefits in mind, the study researchers wanted to see whether castor oil could be beneficial for treating dry eye disease.

The scientists recruited 26 people with the disease caused by blepharitis to participate in the trial. In order to be eligible for the study, the participants could not have had ocular surgery in the past three months, they could not wear contacts during the study, and they had to agree to discontinue the use of any lid hygiene products.

At the beginning of the trial, participants completed questionnaires that assessed their symptoms and participated in eye exams. After these assessments, the scientists instructed the participants to apply castor oil to their bottom and top eyelids in the morning and at night for four weeks.

After the 4-week period was over, the researchers assessed the participants again to see whether there were any improvements in their symptoms.

 

Overall improvement in dry eye symptoms with castor oil

 

Using castor oil as a treatment for dry eye disease showed promise during the month-long trial.

By the end of the trial period, participants saw an overall improvement in their dry eye symptoms.

Some benefits the participants experienced included lessened crusting around the eyelashes and improvement in the eyelid thickening.

The latter is especially significant since that is a hallmark of blepharitis. Any reduction in the eyelid thickening will lead to improvement of other symptoms associated with it as well.

Trial participants also did not have as much redness on their eyelids when they completed four weeks of the castor oil treatment.

“Castor oil has been proposed as a natural product that could offer a safe, effective and easy-to-use alternative to existing therapies,” says study investigator Professor Jennifer Craig.

“My hope is this study will produce evidence-based guidance for clinicians with regard to offering castor oil as a possible management option for patients suffering from blepharitis,” continues Prof. Craig.

 

Castor oil: A cheaper treatment alternative

 

Dr. Cory Bovenzi, a facial plastic surgeon at Smith Cosmetic Surgery based in Denver, Colorado, weighed in on the castor oil trial for Medical News Today. Dr. Bovenzi often treats people with dry eye disease, including performing surgery on the eyelids when necessary.

“Castor oil has a number of properties that may make it a good candidate for treating dry eye disease,” Dr. Bovenzi told MNT. “It acts as an emollient (moisturizing agent) that has a long-lasting effect that may have a longer duration than the current eye drops on the market.”

“It also has antimicrobial and anti-inflammatory effects that may help decrease the amount of microbes that can block or inflame the meibomian glands which normally lubricate the eyes,” Dr. Bovenzi continued.

Dr. Bovenzi thinks that castor oil has the potential to be a cheaper alternative to other treatments for dry eye disease.

“Using castor oil to treat dry eye disease may give more long-lasting and substantial relief to patients who suffer from this condition compared to current treatments available,” said Dr. Bovenzi. “It has been shown to be a safe treatment for other medical applications, and it is promising to see these preliminary reports about another potential use for this relatively cheap and safe treatment option.”

Dr. Bovenzi advises people who have dry eye symptoms to consult their doctors since sometimes it can be a result of an autoimmune disease such as Sjogren’s syndrome.

Since Sjogren’s syndrome can cause vision problems and peripheral neuropathy if it is not properly treated, it is best to consult with a healthcare professional before trying natural remedies to avoid causing long-term damage.

Dr. Margaret Wang French also spoke with MNT about the trial. Dr. Wang French is an assistant professor in the Department of Ophthalmology at UT Southwestern Medical Center in Dallas and is board certified in ophthalmology.

“Their initial study of 26 patients did show improvement in blepharitis, a disease that can cause evaporative dry eye disease,” commented Dr. Wang French. “However, this small pilot study was done without controls or randomization, so they are in the process of studying their hypothesis in a randomized controlled trial — a golden standard for meaningful medical research.”

Dr. Wang French also noted that patients should work with their doctors on a treatment plan.

“Each patient should have a tailored regimen, depending on their subjective issues and objective findings with their dry eye specialist,” noted Dr. Wang French. “Consistency and patience with therapy are the two characteristics that have helped my patients the most.”