Suppressive effects of violet light transmission on myopia progression in a mouse model of lens-induced myopia.

The prevalence of myopia has been steadily increasing for several decades, and this condition can cause extensive medical and economic issues in society. Exposure to violet light (VL), a short wavelength (360-400 nm) of visible light from sunlight, has been suggested as an effective preventive and suppressive treatments for the development and progression of myopia. However, the clinical application of VL remains unclear. In this study, we aimed to investigate the preventive and suppressive effects of VL on myopia progression. Various transmittances of VL (40%, 70%, and 100%) were tested in C57BL/6J mice with lens-induced myopia (LIM). Changes in the refractive error, axial length, and choroid thickness during the 3-week LIM were measured. The myopic shift in refractive error and difference in axial length between the 0 and -30 diopter lens was lessened in a transmission-dependent manner. Choroidal thinning, which was observed in myopic conditions, was suppressed by VL exposure and affected by its transmission. The results suggest that myopia progression can be managed using VL transmittance. Therefore, these factors should be considered for the prevention and treatment of myopia.

Short-Term Exposure to Violet Light Emitted from Eyeglass Frames in Myopic Children: A Randomized Pilot Clinical Trial.

Violet light (VL), 360−400 nm wavelength, is contained in the sunlight and is an effective element for myopia suppression. This study is to investigate the safety and efficacy of novel eyeglasses that emit VL from the frames. This is a double-masked, randomized, pilot clinical trial conducted in a clinic in Japan. Forty-three children with myopia were enrolled. Participants were randomly assigned to two groups, wearing VL-emitting eyeglass frames (VLf) that emitted VL of 310 µW/cm2 (VLf group, n = 22) or pseudo-placebo eyeglass frames with a minimal emission of VL (<10 µW/cm2) (control group, n = 21). The exposure time was 3 h per day. The primary outcomes were visual acuity, tear film break-up time, corneal endothelial cell density, and the slit-lamp/fundus examinations. The secondary outcome was the 6-month changes in the axial lengths and cycloplegic refractions. Forty-one (95%) participants were included; twenty-one in the VLf group and twenty in the control group. No significant differences were seen in any safety evaluation. Significant changes were seen in axial elongation, choroidal thickness, and cycloplegic refractions in the subgroup analysis of 8- to 10-year-old children (p < 0.05), but otherwise no significant differences were seen. The VLf showed short-term safety and effectiveness against myopia progression.

Photobiological Neuromodulation of Resting-State EEG and Steady-State Visual-Evoked Potentials by 40 Hz Violet Light Optical Stimulation in Healthy Individuals.

Photobiological neuromodulation and its clinical application has been investigated in recent years. The response of the gamma-oscillation to human visual stimuli is known to be both burst and resonant in nature, and the coupling between alpha and gamma oscillations may play a functional role in visual processing. To date, there is no study that examined the effects of gamma-frequency violet light (VL) stimulation on human electroencephalography (EEG). In this study, we investigated the neurophysiological changes induced by light stimulation using EEG. The purpose of this study was to evaluate the specific effects of 40 Hz gamma-frequency VL stimulation on EEG activity by comparing the effects of white light (WL) with the same condition. Twenty healthy participants (10 females: 37.5 ± 14.3 years; 10 males: 38.0 ± 13.3 years) participated in this study and the following results were observed. First, when compared with the power spectrum density (PSD) of baseline EEG, 40 Hz-WL induced significant increase of PSD in theta band. Second, compared the PSDs between EEG with 40 Hz-VL and EEG with 40 Hz-WL, 40 Hz-VL induced significantly lower enhancement in delta and theta bands than 40 Hz-WL. Third, when focused on the occipital area, negative peak of VEP with 40 Hz-VL was smaller than that of 40 Hz-WL. Fourth, 40 Hz-VL induced an increase of alpha-gamma coupling during the VEP at the F5 electrode site as well as post-EEG at the C4 electrode site, compared with baseline EEG. Thus, the present study suggested that 40 Hz-VL stimulation may induce unique photobiological neuromodulations on human EEG activity.

Clinical outcomes of KeraVio using violet light: emitting glasses and riboflavin drops for corneal ectasia: a pilot study.

BACKGROUND/AIMS: We developed a novel technology consisting of violet light (VL)-emitting glasses and defined the combination of VL irradiation and riboflavin treatment as KeraVio. Our goal was to evaluate the clinical results of KeraVio in patients with progressive corneal ectasia. METHODS: Eyes were exposed to VL (375 nm, irradiance 310 µW/cm2)-emitting glasses for 3 hours daily for 6 months, and a riboflavin solution was administered onto the corneal epithelium six times during each 3-hour VL irradiation. The primary end point was a change in the maximum keratometry (Kmax) value over 6 months compared with that over the 1 year before baseline. RESULTS: The efficacy of KeraVio was evaluated in 20 eyes with severe progression, and its safety was evaluated in all 40 eyes. The mean changes in Kmax over the 1 year before baseline and during the 6-month observation period were 6.03±3.41 dioptres (D) and -0.81±3.34 D, respectively (p=0.002). At 6 months, the Kmax value decreased by more than 2 D in 4 eyes (20%), remained within 2 D in 13 eyes (65%), and increased by 2 D or more in 3 eyes (15%). The corneal stromal demarcation line was identified in 16 eyes (80%), and its depth was 206.3±54.9 µm at 1 month. No significant decrease in endothelial cell density, lenticular opacity or transient corneal haze was noted. CONCLUSION: Based on our 6-month results, daily treatment of progressive corneal ectasia with KeraVio can halt disease progression without any safety concerns. CLINICAL TRIAL REGISTRATION NUMBER: jRCTs032180217.

Current Prevalence of Myopia and Association of Myopia With Environmental Factors Among Schoolchildren in Japan.

IMPORTANCE: Given the estimates of increasing prevalence of myopia, especially in Asia, it is important to determine the current prevalence of myopia among populations of schoolchildren in Japan. OBJECTIVE: To investigate the current prevalence rate of myopia and the association between environmental factors and myopia in Japanese schoolchildren. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study assessed 1478 participants, including 726 elementary school students and 752 junior high school students, at 2 schools in Tokyo, Japan, who underwent eye examinations from April 1 to May 31, 2017, that included measurement of the refractive errors by autorefractometry with noncycloplegic refraction and ocular biometric factors. After excluding those who had been treated with atropine or orthokeratology (n = 11), had a history of eye disease (n = 2), had no parental consent (n = 41), and were absent (n = 8), 1416 schoolchildren were analyzed. MAIN OUTCOMES AND MEASURES: The primary outcome was the prevalence of myopia and high myopia. Secondary outcomes were environmental factors that were associated with myopia. RESULTS: A total of 1416 schoolchildren (mean [SD] age, 10.8 [2.7] years; 792 [55.9%] male) were studied. The prevalence rates of myopia (spherical equivalent ≤-0.5 diopters [D]) were 76.5% (95% CI, 73.4%-79.7%) among the elementary school students and 94.9% (95% CI, 93.3%-96.5%) among the junior high school students. The prevalence rates of high myopia (spherical equivalent ≤-6.0 D) were 4.0% (95% CI, 2.5%-5.4%) among the elementary school students and 11.3% (95% CI, 8.8%-13.7%) among the junior high school students. The prevalence rates of high myopia classified based on axial length of 26.0 mm or longer were 1.2% (95% CI, 0.4%-2.0%) among elementary school students and 15.2% (95% CI, 12.5%-17.8%) among junior high school students. Multiple regression analysis showed that higher-order aberrations and dry eye disease were associated with refractive error in elementary school students (spherical aberration: ß = 6.152; 95% CI, 3.161-9.143; P < .001; dry eye disease: ß = -0.626; 95% CI, -1.189 to -0.063; P = .03) and with axial length in junior high school students (spherical-like aberration: ß = 26.546; 95% CI, 18.708-34.385; P < .001; dry eye disease: ß = 0.354; 95% CI, 0.131-0.578; P < .002). CONCLUSIONS AND RELEVANCE: Although the use of noncycloplegic autorefraction with a cutoff of -0.50 D could lead to overestimation of results, these findings suggest that the current prevalence rates of myopia among elementary and junior high school students in Asia are high, especially if the results from these 2 schools are generalizable to all schoolchildren in Japan and Asia.

Effect of Ultrasonic Moisture Glasses on Dry Eye Signs and Symptoms.

PURPOSE: This study was undertaken to evaluate the effect of a novel humidifying eyeglass-shaped device-ultrasonic moisture glasses-on dry eye signs and symptoms. METHODS: A total of 18 subjects with dry eye symptoms underwent a crossover test. A water cartridge was set on each temple of the eyeglass-shaped device. All subjects randomly wore the device twice in different settings, each for 10 minutes. Subjects wore the glasses once with the cartridges filled with water (the intervention group), and once with the cartridges empty (the control group). The order was randomized. We evaluated tear film break-up time (TBUT) and fluorescein staining score just before, immediately after, and 10 minutes after wearing the device. We also assessed functional visual acuity (FVA), blink frequency, and visual analog scale (VAS) score just before and immediately after wearing the device. RESULTS: TBUT, blink frequency, and VAS improved in the intervention group (all P < 0.001) and exhibited significant differences between the intervention and control groups. CONCLUSIONS: Wearing the ultrasonic moisture glasses for 10 minutes improved tear stability and decreased dry eye symptoms in this cohort of subjects. TRANSLATIONAL RELEVANCE: These findings show that the ultrasonic moisture glasses are an effective device for improving dry eye signs and symptoms.

Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression.

Prevalence of myopia is increasing worldwide. Outdoor activity is one of the most important environmental factors for myopia control. Here we show that violet light (VL, 360-400nm wavelength) suppresses myopia progression. First, we confirmed that VL suppressed the axial length (AL) elongation in the chick myopia model. Expression microarray analyses revealed that myopia suppressive gene EGR1 was upregulated by VL exposure. VL exposure induced significantly higher upregulation of EGR1 in chick chorioretinal tissues than blue light under the same conditions. Next, we conducted clinical research retrospectively to compare the AL elongation among myopic children who wore eyeglasses (VL blocked) and two types of contact lenses (partially VL blocked and VL transmitting). The data showed the VL transmitting contact lenses suppressed myopia progression most. These results suggest that VL is one of the important outdoor environmental factors for myopia control. Since VL is apt to be excluded from our modern society due to the excessive UV protection, VL exposure can be a preventive strategy against myopia progression.

Calculation of transition probability for neutralization process of +1 ion based on the Noziéres and Dominicis theory.

We investigate the neutralization probability of a +1 ion moving parallel to a metal surface, mainly using the Noziéres and Dominicis theory (ND theory), which was applied to the edge singularities in x-ray absorption and emission spectra in metals. In particular, we focus on the effects due to the sudden disappearance of the image potential in the neutralization process. From the analysis, we found that the neutralization probability is given by [Formula: see text], where D and Γ are the band width and the gamma function. The factor α = 2δ/π-(δ/π)(2) is given by the phase shift (δ: phase shift on Fermi surface), and the energy difference between the initial and final states, Δ, includes the kinetic energy of the ion and various other phenomenological factors. The singularity caused from the sudden disappearance of the image potential enhances or reduces the neutralization probability depending on the symmetry of atomic orbital of the ion. When the ion velocity is too fast to form an image potential, the neutralization process would proceed without the creation of an image potential, accompanying an excitation of a surface plasmon; as a result of plasmon excitation the ion velocity becomes slower than the plasma frequency because of screening effects. In this paper, we apply the ND theory to the case of slow ion motion and discuss the dynamics.