Researchers say laughter therapy may be just as good as drops for treating dry eyes.

Repeating “Hee hee hee, hah hah hah, cheese cheese cheese, cheek cheek cheek, hah hah hah hah hah hah” a number of times a day over an eight-week period might just reduce the symptoms of dry eyes, a study suggests.

Laughter exercise has been trialled for a number of conditions, so international researchers wanted to assess whether it could help patients with dry eye disease.

Dry eye disease is a common condition which occurs when tears are not able to give the eyes enough lubrication, leading to symptoms including itchy, sore and red eyes.

Experts from China, the US and Queen’s University Belfast examined almost 300 people aged 18 to 45 with dry eye disease.

Over eight weeks, half received sodium hyaluronic acid eye drops – also known as artificial tears – while the other half were given laughter therapy.

Researchers wanted to assess whether there was a meaningful change in participants’ score in a measurement of disease called the ocular surface disease index.

Laughter therapy comprises various interventions designed to provoke laughter, smiling and pleasant feelings, the authors wrote in The BMJ.

The research team adapted and developed a laughter exercise to “optimally engage the ocular muscles of participants”.

People taking part in the laughter exercise branch of the latest study viewed an instructional video and people were requested to vocalise the phrases “Hee hee hee, hah hah hah, cheese cheese cheese, cheek cheek cheek, hah hah hah hah hah hah” 30 times per five-minute session.

They were told to do this around four times every day for an eight-week period.

Meanwhile, the other group was instructed to use eyedrops four times daily for eight weeks.

At the end of the study, researchers found that the decrease in the ocular surface disease index score was statistically significant in both groups.

While they said that the biological mechanism of laughter exercise on dry eye disease is “unclear”, they concluded that “laughter exercise was non-inferior to artificial tears (0.1% sodium hyaluronic acid) in improving dry eye disease symptoms and clinical signs”.

The team added: “Laughter exercise is a safe, environmentally friendly, and low-cost intervention for patients with symptomatic dry eye disease and limited corneal staining.”