Public health and animal studies have shown that LED exposure, even at typical indoor lighting levels, can induce photochemical injury, contributing to retinal toxicity and increasing the risk of degenerative diseases like age-related macular degeneration (AMD). Protecting the retina from such damage is crucial for maintaining visual health [[1], [2], [3]].

Recently, full-spectrum LED technology has garnered significant attention. It combines ultraviolet LEDs with red, green, and blue phosphors to achieve a higher color rendering index [4]. This allows the light spectrum to more closely mimic natural sunlight, resulting in superior lighting quality [5]. Our team [6] had confirmed that full-spectrum LEDs could mitigate the light-induced retinal degeneration(LIRD) by modulating endoplasmic reticulum stress. Muralidharan et al. [7] also found full-spectrum LEDs can accelerate the recovery of chickens from form-deprivation myopia.

Theoretical calculations suggested that the more blue light hazard would occur with the rise in correlated color temperature [8]. The overall viability of rMC-1 cells, ARPE-19 cells, and R28 cells decreased as correlated color temperature increased [9]. Chen et al. [10] demonstrated that retinal damage in mice occurs in a correlated color temperature dependent manner. However, the impact of LED exposure with different spectra and correlated color temperature on retinal health remains to be further studied.

Neohesperidin(NHP; IUPAC name: (2S)-7-[(2S,3R,4S,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)-3-[(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxyoxan-2-yl]oxy-5-hydroxy-2-(3-hydroxy-4-methoxyphenyl)-2,3-dihydrochromen-4-one; CAS No. 13241–33-3), a flavanone glycoside composed of the flavanone hesperetin and the disaccharide neohesperidose, is a flavonoid compound found in citrus fruits, such as oranges and grapefruits [11,12]. It is an important active ingredient in traditional Chinese medicines like dried tangerine peel [13], with well-documented anti-inflammatory, antioxidant, and anti-apoptotic properties [[14], [15], [16], [17]]. Notably, oxidative stress and mitochondrial dysfunction are central mechanisms underlying photochemical retinal damage, as excessive blue light exposure generates reactive oxygen species (ROS), disrupts mitochondrial membrane potential, and triggers apoptosis. NHP's antioxidant capacity has been demonstrated to directly scavenge ROS and enhance cellular defense systems by promoting AMPK activity and PGC-1α expression, which activates downstream antioxidant pathways (e.g., SOD, CAT) and improves mitochondrial homeostasis [18]. Therefore, we hypothesize that NHP could attenuate LED-induced ROS overproduction, stabilize mitochondrial membrane potential, and inhibit apoptosis in retinal cells, thereby preserving photoreceptor viability.

In this study, we established in vivo and in vitro LED exposure models. In detail, four different lights would be applied: 2700K conventional LEDs (CL-2700K), 2700K full-spectrum LEDs (FL-2700K), 5000K conventional LEDs (CL-5000K), and 5000K full-spectrum LEDs (FL-5000K). We compared the effects of spectra and correlated color temperature on rodents and 661W cells, and evaluated the therapeutic effects of NHP on light-induced damage. Our results indicate that 2700K full-spectrum LED is least toxic lighting solution to retinal health. It also found that NHP can induce mitochondrial autophagy to mitigate photochemical damage.