Blue Light-Induced Retinal Neuronal Injury and Amelioration by Commercially Available Blue Light-Blocking Lenses

Abstract

Blue light exposure-induced retinal damage has been extensively studied. Although many in vitro studies have shown the benefits of blue light-blocking lenses (BBL) there have been few comprehensive in vivo studies to assess the effects of BBL. We investigated the influence of blue light exposure using light-emitting diodes on retinal histology and visual cortex neurons in rodents. We also considered whether retinal and cortical changes induced by blue light could be ameliorated with blue light-blocking lenses. A total of n = 24 (n = 6 in each group; control, light exposure without lenses, two different BBLs)) male Wistar rats were subjected to blue light exposure (LEDs, 450–500 lux) without or with BBLs (400–490 nm) for 28 days on a 12:12 h light–dark cycle. Histological analysis of retinae revealed apoptosis and necrosis of the retinal pigment epithelium (RPE), photoreceptors, and inner retina in the light exposure (LE) group, along with increase caspase-3 immunostaining in the ganglion cell layer (p < 0.001). BBL groups showed less caspase-3 immunostaining compared with the LE group (p < 0.001). V1-L5PNs (primary visual cortex layer 5 pyramidal neurons) demonstrated reduced branching and intersections points for apical (p < 0.001) and basal (p < 0.05) dendrites following blue light exposure. Blue light-blocking lenses significantly improved the number of basal branching points compared with the LE group. Our study shows that prolonged exposure to high levels of blue light pose a significant hazard to the visual system resulting in damage to the retina with the associated remodeling of visual cortex neurons. BBL may offer moderate protection against exposure to high levels of blue light.

Blue-Light-Blocking Lenses Ameliorate Structural Alterations in the Rodent Hippocampus

“…In a previous study employing the same light exposure protocol, the retina was thinned and neurons in layer 5 of the visual cortex were negatively impacted, particularly with reductions in basal dendrites [31,45]. The current data show that similar changes were also present in the hippocampus.…”

“…Ours and other studies have shown that the retina is severely damaged by prolonged exposure to short-wavelength light [14,31,50]. Even after the degeneration of photoreceptors, there was evidence of ongoing apoptotic activity, as indicated by caspase 3 staining of the inner retinal and retinal ganglion cells [31]. It is likely that such injury would result in altered input into the hippocampus from ipRGCs.…”

“…Commercially available BBLs, in the form of spectacle lenses or intraocular lenses (IOLs), have been claimed to reduce eyestrain, enhance sleep quality, prevent retinal toxicity, and slow the progression of age-related macular degeneration (AMD) [30]. In a previous study using a rodent model, BBLs provided protection for visual cortex pyramidal neurons against chronic exposure to high levels of short-wavelength light from LEDs [31]. However, to the best of our knowledge, the impact of short-wavelength light exposure on animal behavior and hippocampal neuron morphology is yet to be examined.…”

Light Pollution and Oxidative Stress: Effects on Retina and Human Health

“…In the interim, it is crucial to minimize excessive light exposure. Several measures have been proposed to achieve this [ 13 , 168 , 169 , 170 ]. Exposure to morning sunlight is recommended to help maintain synchronized rhythms, along with the use of blue light cutting glasses and blue light cutting base makeup.…”

Effect of Light Emitting Diodes (LED) Exposure on Vitreous Metabolites-Rodent Study

“…The white and blue LEDs have high energetic characteristics compared with other traditional light sources, so the potential ocular and general risks of these LEDs are widely explored [ 4 , 19 , 21 , 22 , 23 , 24 , 25 ]. The short-term (28 days) exposure to moderate blue light causes nebulous metabolites in the vitreous [ 26 ] and changes in retinal tissues and cortical neurons [ 27 , 28 ]. Inference from these studies cannot be generalized because few studies have suggested that low levels of blue light for a longer duration (a few months to years) are needed to determine the effects of blue light on the visual system [ 29 ].…”