Myopia is a common refractive error that has reached near-epidemic proportions globally. Characterized by an elongation of the eyeball, myopia can lead to significant visual impairment and is a leading cause of blindness worldwide. In response to this growing public health concern, researchers have explored various environmental factors that may influence myopia progression, with light therapy emerging as a promising intervention. In this page we will review the current understanding of how different wavelengths of light, including red, violet, and blue light, impact myopia development and can be utilized in clinical practice.

Red Light Therapy: the most effective light for myopia control

Red light therapy, typically involving wavelengths around 650 nm, has been extensively studied for its effects on myopia control. Clinical trials and meta-analyses have consistently shown that red light can significantly slow down the axial length (AL) elongation—a critical marker of myopia progression. The mechanism behind red light's effectiveness is thought to be linked to its ability to penetrate deep into the eye, and possibly influencing biochemical processes involved in eye growth. Red light may enhance mitochondrial efficiency in retinal cells, leading to decreased oxidative stress and improved cellular health. This hypothesis, while promising, underscores the need for further research to fully understand the mechanisms.

Red Light Therapy Devices

Red-light therapy: Several manufacturers offer repeated low-level red light (RLRL) products in this innovative field. However, the light design, user interface, and additional features such as treatment session tracking, parental controls and regulatory approvals can differ. The most commonly-used device is from Eyerising (Suzhou Xuanjia Optoelectronics Technology, China). It emits a wavelength of 650nm at a laser power of 0.29mW and was used in 16 studies in diverse groups, including children with pre-myopia, non-highly myopia and high myopia. It is designed for at-home use, requiring only 3 minutes of use, twice a day, with at least a 4-hour interval between uses.

Other Light Therapies

Violet light therapy (360-400 nm) and cyan light therapy (around 483 nm) have shown promising potential in myopia management. Animal studies suggest that both wavelengths can help inhibit axial elongation, a key indicator of myopia progression, by modulating biochemical processes related to eye growth. While the results from animal models are encouraging, human studies are still in early stages, and further research is needed to confirm the long-term efficacy and safety of violet and cyan light therapies.

Full-spectrum light therapy, which mimics the broad range of wavelengths found in natural sunlight, is also under investigation. Clinical studies have linked increased outdoor sunlight exposure to slower myopia progression in children. This has led to studies exploring whether boosting indoor light intensity can replicate these benefits. However, indoor lighting cannot fully replicate the intensity and spectral composition of natural sunlight, which poses challenges in replicating the effects of outdoor exposure. More research is needed to fully understand the role of full-spectrum light in myopia control.