## 1 Introduction  
Glaucoma is an ophthalmic disease that affects around 1% of people aged over 40 years, 5% of people aged 70 years and older, and 10% of those older than 80 years [1], and it can lead to irreversible blindness. The studies on the glaucoma diffusion in the next years show that 112 million of people are expected to loose their vision by 2040 [1, 2].  
The open-angle glaucoma is the most widespread type of this disease, and it is related to the ocular hypertension which causes an impairment of retinal ganglion axons cells [3, 4, 5, 6, 7], which make up the optical nerve, resulting in a progressive loss of retinal ganglion cells [8, 9, 10]. At present, the clinical treatments are aimed at lowering the intraocular pressure with the intent of increasing the duration of patients vision. However, vision is not only related to eyes. Indeed, it is the result of a complex information processing that occurs in the brain. Thus, to treat damage to it, a holistic approach is needed to support the actual treatments [11], improving the reduced information flow that reaches the brain [12, 13, 14], optimising the entire process.  
Recently, a thermodynamic approach to glaucoma and a thermophysical model the optic nerve behaviour have been developed [15]: the thermodynamic analysis pointed out the possible modification of the behaviour of the optical nerve by changing in the membrane electric potential.  
Moreover, the thermophysical results highlighted also that a control of the membrane electric potential could produce regeneration, because the supply of energy generates ion fluxes, with a consequent change in the membrane electric potential.  
Consequently, we argued that a possible way to supply energy could be the use of visible light [15], in relation to the recent evidences that photostimulation can promote regeneration and functionality after nerve injury [16; 17; 18], and to the experimental and clinical results of the effect of a non-thermal low dose light emitting diode (LED) array on human cells [19; 20]. Indeed, electrical activity has a fundamental role in stimulating the regrowth potential of the central nervous system neurons [21; 22].  
However, these theoretical results have been only a possible hypothesis of new complementary therapies. So, an experimental approach has been developed, to obtain evidence, in order to design a new visible light complementary therapy for glaucoma. Indeed, photo-stimulation has just been used in neuromodulation [23]: neural stem cells have been shown to express blue/red light-sensitive photoreceptors [24]. Moreover, the proliferation and regulation of neural stem cells to neuronal or glial cells are wavelength-specific; indeed, low-power (300 \(\mu\)W cm\({}^{-1}\)) monochromatic blue light (455 nm wavelength) was shown to increase astrocyte differentiation. The behaviour of the neurones of the central nervous system depends on mitochondrial generated ATP, and four major mitochondrial protein complexes related to the generation of ATP present interaction with light of different wavelengths [25].  
So, in this paper we summarise a first experimental approach to evaluate the use of visible light as a possible support to contrast glaucoma, as the thermophysical model suggests. The results obtained represent a new viewpoint to introduce the visible light as a support to the pharmacological therapies, in order to improve the quality of life of the patients.