Rats in the experimental group were exposed to harmful blue light derived from a light-emitting diode (LED) with a wavelength of 450 nm and an intensity of 1000 lux for 28 days, 12 hours a day, while the control group of rats were exposed to white light with an intensity of 400 lux for the same period of time.
Long-term exposure to harmful blue light led to a decrease in tear film stability
In the experiment, the TBUT (tear film breakup time) parameter was analysed, which evaluates the stability of the tear film and is used in the diagnosis of dry eye. After 28 days, the group exposed to blue light had a significantly shorter TBUT than at the onset; the control group also reported the shortening of the TBUT, but the blue group’s score was significantly worse.
Exposure to both blue and white light caused changes on the surface of the eye and in the corneal epithelium
Changes on the ocular surface were assessed by fluorescein stain in the cornea, which reveals epithelial disruption. In the group exposed to blue light the stain score was already higher on day 14, and this trend continued until the last day 28. The control group only showed increased staining after 28 days. These results suggest significantly greater damage to the corneal epithelium with prolonged exposure to blue light. The blue group also reported increased secretion of pro-inflammatory markers.
