Low-level light therapy (LLLT), also known as photobiomodulation, has recently become more widely accessible as a treatment for dry eye disease (DED) in New Zealand. LLLT is believed to work by triggering conformational changes in the cellular cytochrome-c oxidase enzyme, leading to enhanced mitochondrial function, increasing adenosine triphosphate (ATP) production¹. ATP production is important as it improves cellular function of treated tissues, such as those involved in the lacrimal functional unit. Other reported therapeutic benefits from LLLT in dry eye disease include heat delivery to treatment area²-⁴, reduction of oxidative stress⁵ and reduced inflammation⁶.
Light wavelengths between 390–600nm are used to treat superficial tissue with a possible antimicrobial effect, whereas wavelengths between 630–1,000nm can reach deeper tissues⁷,⁸. Wavelengths of around 633nm are recommended in the treatment of DED. While the treatment protocol can vary, recent studies have tended to opt for 15-minute treatments, delivered with varying frequency and spacing between treatment sessions, within the manufacturer’s guidelines, tailored to suit individual patients.
A randomised controlled trial (RCT) was conducted in South Korea in 2022 comparing LLLT treatment to sham treatment in a cohort of 40 participants with DED. Treatment was provided twice a week for three weeks with follow-up measurements taken at four weeks from baseline. The active LLLT group experienced significant improvements in corneal and conjunctival staining, Schirmer test and upper lid meibography, compared with the sham treatment group. However, since the study authors did not report a significant change from baseline to week four in either group, the extent of improvement is difficult to ascertain in the LLLT group⁸.
