Combinatorial lutein, zeaxanthin, and spearmint extract attenuated intense LED-induced intraocular pressure elevation and oxidative stress in the retina and anterior segment

Prolonged exposure to high-intensity light-emitting diode (LED) illumination can provoke retinal dysfunction accompanied by intraocular pressure elevation. We evaluated whether an oral formulation containing lutein, zeaxanthin, and spearmint extract attenuated the impairing effects caused by intense LED exposure in mice, using topical latanoprost as a pharmacological benchmark for lowering intraocular pressure. Female ICR mice (6 weeks) were assigned to control, LED damage, combined lutein-zeaxanthin-spearmint (0.25× or 1.0×), lutein-zeaxanthin, spearmint extract, or latanoprost groups. All supplements were administered daily by oral gavage, and latanoprost was instilled daily (days 1–37). LED exposure (5000 lx, 24 h/day) was applied on days 17–37. Intraocular pressure was measured on days 15, 22, 29, and 36; scotopic electroretinography (ERG) was measured on days 16, 23, 30, and 37. Whole-eye sections were analyzed for retinal thickness and immunostaining for RPE65, 8-OHdG, and 4-HNE. Cornea, iris, ciliary body, and trabecular meshwork were assessed for 8-OHdG, 4-HNE, AQP1, and AQP4. The results showed that LED exposure reduced ERG a- and b-wave amplitudes and retinal thickness, particularly in the outer nuclear layer, which none of the treatment regimens prevented. However, the combined lutein-zeaxanthin-spearmint attenuated LED-induced retinal 8-OHdG and 4-HNE upregulation and mitigated RPE65 loss. LED exposure elevated intraocular pressure on days 29 and 36, which the combined lutein-zeaxanthin-spearmint attenuated. The combined lutein-zeaxanthin-spearmint also reduced oxidative injury in the cornea, iris, ciliary body, and trabecular meshwork but did not prevent LED-associated AQP1 and AQP4 downregulation in the ciliary body. Collectively, the combined formulation attenuated oxidative injury in the retina and anterior segment and partially stabilized intraocular pressure under intense LED exposure, but did not rescue retinal dysfunction or thinning.