Blepharitis, simply defined as eyelid inflammation, is one of the common ocular conditions associated with discomfort and irritation. Because blepharitis causes meibomian gland dysfunction and dry eye, this study aimed to confirm the effect of photobiomodulation (PBM) on blepharitis.
A total of 20 rats were randomly assigned to 4 equal groups, including control, blepharitis, PBM, and eye drop. Blepharitis was induced in rats by injecting complete Freund’s adjuvant in the eyelid margins. PBM intervention was given every 3 days after blepharitis induction. Clinical signs including tear volume, tear breakup time (TBUT), meibomian gland swelling, fluorescein, telangiectasia, and meibomian gland secretion scores were measured every week, and the rats were killed for histological analysis after 4 weeks. Immunohistochemistry was performed to compare the level of inflammatory cytokines, interleukin-1β and tumor necrosis factor-α, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining on retina was performed to observe any retinal damage.
Tear volume and TBUT increased with PBM intervention, and with improved eyelid swelling, corneal staining, telangiectasia, and meibomian gland secretion scores increased. Hematoxylin and eosin staining showed no structural abnormalities of meibomian gland caused by blepharitis induction. Immunohistochemistry revealed that the levels of inflammatory cytokines interleukin-1β and tumor necrosis factor-α were lowered with PBM treatment in both eyelid and conjunctiva. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining showed no retinal damage.
Laser PBM at 808 nm was effective in alleviating ocular signs and controlling inflammation in blepharitis rat model. The in vivo results suggest that PBM has the potential to be used in treating blepharitis patients.