Transcutaneous Auricular Vagus Nerve Stimulation in Dry Eye Disease With Meibomian Gland Dysfunction

"taVNS device (Elmmedicare, EC100, Shenzhen, China) was used to apply stimulation for patients. Stimulation parameters comprised an electrical current of 1 mA at a frequency of 20 Hz, with a waveform width of 1 ms. Repurposed off-the-shelf devices were utilized for this purpose, with the stimulator generating single square-wave pulses lasting 1 ms each. Enhancing conductivity was achieved by wiping the ear with tap water.~The electrodes were placed on the cymba conchae and concha around the affected ear, which is the region of rich vagus nerve branch distribution. Patients in control group were applied using the same stimulator, stimulation parameters and same sessions. However, the electrodes were placed on the antihelix around the affected ear, which is the region of few vagus nerve branch distribution."

Participants in both groups received hyaluronic acid eye drops (HYLO COMOD® eye drops, Ursapharm, Ltd., Germany) with the treatment of 3 times a day.