Let’s first talk about what 311nm and 308nm here mean. 311 and 308 both refer to the therapeutic wavelength output by the phototherapy equipment, in nm. They are all in the part of the ultraviolet band that has special therapeutic effects (296 ~ 313nm), and they are all classified into the category of narrow-band mid-wave ultraviolet (NB-UVB) for clinical use.
In 1981, Parrish and Jaenike et al. found that UVB with a wavelength of 311 to 313 nm not only had a rapid onset of effect in the treatment of psoriasis, but also had an efficacy equal to or even better than that of photochemotherapy and had fewer adverse reactions. Since 1984, it has been widely used in the clinical treatment of various skin diseases such as psoriasis, vitiligo and atopic dermatitis.
After years of use and continuous improvement, there are many models and varieties of home phototherapy devices, with irradiation areas ranging from several square centimeters to full-body irradiation types, which can be suitable for the treatment of skin lesions on any part of the body.
308nm phototherapy equipment has three light sources, namely 308 excimer laser, 308 excimer light and LED. 308 excimer laser was first invented in the United States. In 2000, the US FDA approved it for use in the field of dermatology treatment; in 2005, the 308 excimer laser entered China through the State Food and Drug Administration. The 308 phototherapy device has strong power and takes a short time to reach the cumulative dose; the light spot is small and only irradiates the skin lesions. It is targeted phototherapy and is more suitable for the treatment of small areas of skin lesions; but the price is relatively high.
Correctly choosing a home phototherapy device is an important step in home phototherapy. It is also an important measure to improve the efficacy and reduce adverse reactions. It is indeed a practical issue that every home phototherapy patient faces, but there is no need to get entangled. NB-UVB with peaks at 311nm and 308nm can effectively treat vitiligo. When the cumulative dose is reached, there is no significant difference in efficacy; vitiligo is a chronic disease that requires comprehensive treatment, and phototherapy is only one of the treatment measures.
Regarding whether to choose 311nm or 308nm home phototherapy equipment, a rigid comparison cannot be made. Patients need to analyze specific issues based on their own situation and market products. It is generally recommended to consider comprehensively based on the size, location, and economic conditions of the skin lesion. But no matter what, you must purchase a phototherapy device approved by sFDA, with a "Medical Device Registration Certificate of the People's Republic of China" and the object of use in the registration certificate clearly marked "for patients' own use".
