Short-Term Results of Photobiomodulation Using Light-Emitting Diode Light of 670 nm in Eyes with Age-Related Macular Degeneration

Optimal Timing of Photobiomodulation Therapy for Retinal Diseases: Leveraging Circadian Mitochondrial Rhythms

Age-related retinal degeneration is associated with mitochondrial dysfunction. Emerging evidence suggests that photobiomodulation therapy (PBMT) using near-infrared light may improve mitochondrial function and visual performance, but its efficacy is critically time-dependent. This article explores how daily biological rhythms and mitochondrial function interact, focusing on the potential of timed PMBT for age-related eye diseases. Further research is needed to determine optimal treatment times and individual responses to maximize this therapy's benefits.

Molecular Mechanisms of Vitamin E in Ocular Neurodegenerative Disorders: An Update on the Emerging Evidence and Therapeutic Implications

Vitamin E is renowned for its potent antioxidant properties, crucial for shielding cells against oxidative stress and damage. Deficiency in this vitamin can lead to various health issues, including neurodegenerative diseases, due to its pivotal role in preserving cell membrane integrity and combating cellular oxidative damage. While its importance for overall health, including neurodegeneration, is acknowledged, the specific correlation between vitamin E deficiency and distinct ocular neurodegenerative disorders need to be further explored. This review delves into the molecular mechanisms of vitamin E in ocular neurodegenerative disorders; diabetic retinopathy, age-related macular degeneration, glaucoma, and cataracts, and emphasising the therapeutic implications drawn from existing evidence. Relationship between vitamin E and ocular neurodegenerative disorders is widely researched on, with its primary protective mechanisms attributed to its antioxidant and anti-inflammatory properties. However, studies on the supplementation of vitamin E among human subjects present mixed results, suggesting its complexities and variability depending on factors such as the specific disorder, disease stage, genetic differences, and form of vitamin E utilized. In conclusion, while vitamin E holds promise in mitigating ocular neurodegeneration through its antioxidant and anti-inflammatory properties, its supplementation's efficacy remains nuanced and context dependent. More research works are essential to elucidate its precise role and therapeutic potential in combating various ocular neurodegenerative disorders.

Short-Term Results of Multiwavelength Photobiomodulation in Retinitis Pigmentosa

Objective

To assess the short-term effects of Multiwavelength Photobiomodulation (LumiThera Valeda Light Delivery System) on retinal functional behavior in patients with retinitis pigmentosa (RP).

Materials and Methods

Twelve RP patients (24 eyes) underwent treatment involving nine photobiomodulation (PBM) sessions using the Valeda system, which emits three distinct wavelengths within the yellow (590 nm; 4 mW/cm2), red (660 nm; 65 mW/cm2), and near-infrared (NIR) (850 nm; 0.6 mW/cm2) spectrum. All evaluations were conducted four weeks post-therapy. The treated eye was compared with baseline (pre-therapy). Following nine PBM sessions, assessments included best-corrected visual acuity (BCVA), retinal sensitivity, and characteristics of the correction area via fundus automated perimetry using the Compass system. Additionally, a functional and structural assessment of the retina was performed using multifocal electroretinography (ERG), optical coherence tomography (OCT), fluorescence retinography (FR), and autofluorescence (AF). Statistical analysis employed the Student's t-test for paired samples at a 95% confidence level (p-value ≤ 0.05).

Results

LogMAR-based visual acuity assessment demonstrated an improvement in mean value from 0.62 to 0.53 logMAR, with a statistically significant p-value of 0.001. Visual field examination, based on mean deviation (MD), pattern standard deviation (PSD), and fundal perimeter deviation index (FPDI) parameters, showed improvement from -19.87 dB to -19.45 dB, 9.77 dB to 9.76 dB, and 37% to 39%, respectively, although with non-significant p-values of 0.366, 0.446, and 0.245, respectively. No adverse effects or abnormalities in optical coherence tomography (OCT) and electroretinogram (ERG) were observed during the follow-up period.

Conclusion

In this short-term study, PBM appeared to have the potential to enhance BCVA and fundus automated perimeter in RP patients without causing significant adverse events. However, further assessment with a larger patient cohort and longer follow-up is warranted to ascertain the efficacy of this technique in these patients.

Photobiomodulation use in ophthalmology - an overview of translational research from bench to bedside

Photobiomodulation (PBM) refers to the process in which wavelengths of light are absorbed by intracellular photoacceptors, resulting in the activation of signaling pathways that culminate in biological changes within the cell. PBM is the result of low-intensity light-induced reactions in the cell in contrast to thermal photoablation produced by high-intensity lasers. PBM has been effectively used in the clinic to enhance wound healing and mitigate pain and inflammation in musculoskeletal conditions, sports injury, and dental applications for many decades. In the past 20 years, experimental evidence has shown the benefit of PBM in increasing numbers of retinal and ophthalmic conditions. More recently, preclinical findings in ocular models have been translated to the clinic with promising results. This review discusses the preclinical and clinical evidence of the effects of PBM in ophthalmology and provides recommendations of the clinical use of PBM in the management of ocular conditions.

Light stimulation of mitochondria reduces blood glucose levels

Mitochondria regulate metabolism, but solar light influences its rate. Photobiomodulation (PBM) with red light (670 nm) increases mitochondrial membrane potentials and adenosine triphosphate production and may increase glucose demand. Here we show, with a glucose tolerance test, that PBM of normal subjects significantly reduces blood sugar levels. A 15 min exposure to 670 nm light reduced the degree of blood glucose elevation following glucose intake by 27.7%, integrated over 2 h after the glucose challenge. Maximum glucose spiking was reduced by 7.5%. Consequently, PBM with 670 nm light can be used to reduce blood glucose spikes following meals. This intervention may reduce damaging fluctuations of blood glucose on the body.

Photobiomodulation Using Light-Emitting Diode (LED) for Treatment of Retinal Diseases

Photobiomodulation (PBM) is a type of phototherapy that employs light-emitting diodes (LEDs) or low-power lasers to selectively administer specific wavelengths of visible light, ranging from 500 to 1000 nm, including near-infrared (NIR) wavelengths. LEDs are advantageous compared to lasers due to their ability to treat large areas at a lower cost, lack of tissue damage potential in humans, and reduced risk of eye-related accidents. The ophthalmology community has recently taken interest in PBM as a promising novel approach for managing various retinal conditions such as age-related macular degeneration, retinopathy of prematurity, retinitis pigmentosa, diabetic retinopathy, Leber's hereditary optic neuropathy, amblyopia, methanol-induced retinal damage, and potentially others. This review critically assesses the existing body of research on PBM applications in the retina, focusing on elucidating the underlying mechanisms of action and evaluating the clinical outcomes associated with this therapeutic modality.

Considerations for the Use of Photobiomodulation in the Treatment of Retinal Diseases

Photobiomodulation (PBM) refers to the beneficial effect produced from low-energy light irradiation on target cells or tissues. Increasing evidence in the literature suggests that PBM plays a positive role in the treatment of retinal diseases. However, there is great variation in the light sources and illumination parameters used in different studies, resulting in significantly different conclusions regarding PBM's therapeutic effects. In addition, the mechanism by which PBM improves retinal function has not been fully elucidated. In this study, we conducted a narrative review of the published literature on PBM for treating retinal diseases and summarized the key illumination parameters used in PBM. Furthermore, we explored the potential molecular mechanisms of PBM at the retinal cellular level with the goal of providing evidence for the improved utilization of PBM in the treatment of retinal diseases.

Systemic glucose levels are modulated by specific wavelengths in the solar light spectrum that shift mitochondrial metabolism

Systemic glucose levels can be modulated with specific solar wavelengths that influence mitochondrial metabolism. Mitochondrial respiration can be modulated using light that shifts ATP production with exceptional conservation of effect across species, from insects to humans. Known wavelengths have opposing effects of photobiomodulation, with longer wavelengths (660–900 nm red/infrared) increasing ATP production, and 420 nm (blue) light suppressing metabolism. Increasing mitochondrial respiration should result in a greater demand for glucose, and a decrease should result in a reduced demand for glucose. Here we have tested the hypothesis that these wavelengths alter circulating glucose concentration. We first established an oral glucose tolerance test curve in a bumblebee model, which showed sustained increase in systemic glucose beyond that seen in mammals, with a gradual normalisation over eight hours. This extended period of increased systemic glucose provided a stable model for glucose manipulation. Bees were starved overnight and given a glucose load in the morning. In the first group glucose levels were examined at hourly intervals. In the second group, bees were additionally exposed to either 670 nm or 420 nm light and their blood glucose examined. Increasing mitochondrial activity with 670 nm light at the peak of circulating glucose, resulted in a significant 50% reduction in concentration measured. Exposure to 420nm light that retards mitochondrial respiration elevated systemic glucose levels by over 50%. The impact of 670 nm and 420 nm on mitochondria is highly conserved. Hence, different wavelengths of visible light may be used to modulate systemic metabolism bidirectionally and may prove an effective agent in mammals.