Protective effects of blue light-blocking shades on phototoxicity in human ocular surface cells

Abstract

ObjectiveBlue light hazards for retina and ocular surface have been repeatedly described and many protective methods are introduced for retina; however, no study has been conducted on ocular surface protection. The purpose of this in vitro study was to examine phototoxicity and shade protection after blue light irradiation in primary human cells of corneal surface origin.Methods and analysisPrimary human cells of corneal surface origin were obtained from eye bank eyes. After blue light irradiation (405 nm) of these cells for 3 min, and a further 24 hours’ incubation, surviving viable cells were assessed by the methyl thiazolyl tetrazolium assay. Simultaneously, cell viability was determined in wells covered by ultraviolet and blue light shades.ResultsUnder subconfluent conditions, viable cells decreased by around 50% after blue light irradiation, compared with control cells without irradiation. The blue light phototoxicity was not blocked by the control shade, but the ultraviolet-blocking and blue light-blocking shades protected the cells from phototoxicity, producing a 30%–40% reduction (ultraviolet) and 15%–30% reduction (blue light) in viable cells.ConclusionThese results indicate that blue light injures ocular surface cells and the cells are protected from damage by a shade. We recommend blue light protection to maintain ocular health, especially in high-risk populations, such as people with dry eye, contact lens users, the malnourished and the elderly.

Loss of Concentration May Occur by Blink Inhibition in DED Simulation Models

“…The KANSEI analyzer successfully captured the difference in the state of mind between spontaneous blinking and suppressed blinking. According to previous investigations, there may be local and central events involved in blinking and three possible roles of blinking could be involved in our observations: (1) keeping a healthy ocular surface for optical performance [32][33][34][35]; (2) relieving eye fatigue by filtering blue light irradiation into the eye [36][37][38][39][40][41]; and (3) vision suppression [42][43][44]. In the first role, blinking keeps the ocular surface wet and smooth by interrupting evaporation and wiping the ocular surface to spread tear components.…”

“…Secondly, blinking and eye closures function as photoprotection for preventing ocular surface [36,37] and retinal [38] damage, and relieving eye fatigue [39][40][41] by reducing ultraviolet and blue light irradiation into the eye. We previously proposed a hypothesis [40] that trigeminal activation might occur in conditions where photophobia/photoallodynia is a presenting symptom of eye fatigue, involving systems that alter melanopsin-based signaling from intrinsically photosensitive retinal ganglion cells [41].…”

Comparative Efficiency of Lutein and Astaxanthin in the Protection of Human Corneal Epithelial Cells In Vitro from Blue-Violet Light Photo-Oxidative Damage

“…Besides, the eye surface may also suffer from photo-oxidative damage, and a battery of enzymatic and non-enzymatic antioxidants are present in the anterior segment of the eye to protect its structure from such damage [46]. Human corneal epithelial cells in vitro are damaged and lose viability after exposure to blue light, and such damage could be attenuated by blue light-filtering lenses [47]. Along the same line, Marek and colleagues demonstrated that photooxidative damage was worsened in presence of hyperosmolar stress (as it happens in dry eye patients), thus resulting in increased inflammation and disturbed mitochondrial membrane potential, finally turning on the cell antioxidant response based on the glutathione system.…”

Corneal Opacity Induced by Light in a Mouse Model of Gelatinous Drop-Like Corneal Dystrophy

“…First, light-damaged corneal epithelial cells undergo mitosis and there may be a consequent change in their proliferative activity. 30,31 Second, light-induced oxidative stress in the cornea provokes a strong inflammatory reaction. 32 More experiments using this mouse will be needed to clarify the exact mechanism, and these experiments will hopefully lead to the development of a new method for preventing disease progression.…”