Retinal Protection from LED-Backlit Screen Lights by Short Wavelength Absorption Filters.

(1) Background: Ocular exposure to intense light or long-time exposure to low-intensity short-wavelength lights may cause eye injury. Excessive levels of blue light induce photochemical damage to the retinal pigment and degeneration of photoreceptors of the outer segments. Currently, people spend a lot of time watching LED screens that emit high proportions of blue light. This study aims to assess the effects of light emitted by LED tablet screens on pigmented rat retinas with and without optical filters. (2) Methods: Commercially available tablets were used for exposure experiments on three groups of rats. One was exposed to tablet screens, the other was exposed to the tablet screens with a selective filter and the other was a control group. Structure, gene expression (including life/death, extracellular matrix degradation, growth factors, and oxidative stress related genes), and immunohistochemistry in the retina were compared among groups. (3) Results: There was a reduction of the thickness of the external nuclear layer and changes in the genes involved in cell survival and death, extracellular matrix turnover, growth factors, inflammation, and oxidative stress, leading decrease in cell density and retinal damage in the first group. Modulation of gene changes was observed when the LED light of screens was modified with an optical filter. (4) Conclusions: The use of short-wavelength selective filters on the screens contribute to reduce LED light-induced damage in the rat retina.

Development of a Method to Potentially Substitute Direct Evaluation of Mesopic Visual Acuity in Drivers.

(1) Background: In mesopic lighting conditions, or under adverse environmental circumstances, visual information is reduced, which increases the risk of traffic accidents. This effect could be reduced with a precise evaluation of the visual function under mesopic conditions, but it is difficult to replicate in clinics. This study aims to develop an easy-to-adopt method to evaluate mesopic visual acuity (VA) in drivers. (2) Methods: Prospective and observational study in drivers. logMAR mesopic VA was compared with photopic VA measured under different combinations of contrast charts and filters to find the combination that responds best to mesopic conditions. (3) Results: Fifty-six drivers were examined. The best correlation was found with an 80% density filter and a Weber contrast chart of 20%. The logMAR VA for this combination was 0.01 ± 0.11, which was close to the mesopic VA values (0.01 ± 0.12). The difference between both logMAR VA was 0.00 ± 0.06 (R = 0.86; p ≤ 0.001; ICC = 0.86). (4) Conclusions: The use of 20% contrast optotypes and the interposition of an 80% filter under photopic conditions provide VA values similar to those measured under mesopic lighting conditions, making this simple system a good predictor of mesopic VA values.

Mesopic pupillary reflex in patients treated with fluoxetine.

INTRODUCTION: currently the treatment of mental illness by antidepressants is very frequent. Selective serotonin reuptake inhibitors are the most prescribed antidepressants worldwide and have been associated with alterations in accommodation or pupil. The objective of this study is to evaluate the effects of fluoxetine on the pupillary reflex and the accommodation in young population. METHODOLOGY: The study group included seven patients diagnosed with depression and treated with fluoxetine; 22 subjects were included as a control group. The pupillary reflexes and the accommodative state were evaluated using the Power Refractor II pupilometer. Five phases of 3 seconds each were measured. In phase 2 there was a glare with a white light. RESULTS: For the pupil diameter, maximum and minimum values were obtained in the group of patients treated with fluoxetine than in the control in all the measurement phases. For the control group, a maximum pupillary contraction is observed in the glare phase, however, in the study group it is observed in the phase after glare. As for the accommodation, there are no significant differences between the two groups. CONCLUSIONS: In patients treated with fluoxetine there are pupillary alterations like a bigger pupillary diameters and slower pupillary contraction. The lack of conclusive results in terms of accommodation does not mean that there are no changes related to it, whose detection requires future studies with different methodologies and with a larger sample size.

Clinical application of bicylindric intraocular lens power calculation method.

Purpose: To analyze the reliability of the refractive results prediction obtained in intraocular lens (IOL) calculation using bicylindric power calculation method, with the use of steep and flat keratometry readings compared with the classical mean keratometry calculation method. Methods: Fifty-seven eyes of 57 subjects who underwent cataract surgery were included in this prospective study. Optical biometry was performed with IOLMaster 700 and IOL power calculation was performed using both keratometry readings and the surgically induced astigmatism. Four weeks after surgery, subjective refraction was done. Finally, results obtained with both IOL calculation methods were compared. Results: Mean spherical equivalent using bicylindric IOL power calculation method was -0.082 ± 0.296D, and achieved mean spherical equivalent using classical IOL power method with Haigis formula was -0.088 ± 0.405D. Achieved mean spherical equivalent obtained in subjective refraction after surgery was -0.101 ± 0.265D. Linear correlation between bicylindric method spherical equivalent calculation and achieved spherical equivalent was statistically significant (r = 0.761, P < 0.001), also correlation between Haigis spherical equivalent calculation and achieved spherical equivalent was statistically significant (r = 0.339, P = 0.010). Emmetropia was achieved in 49 of 57 (85.86%) subjects and bicylindric method calculated that 49 of 57 (85.86%) of subjects would get emmetropia (P = 1.000). Classical IOL power calculation estimated that 38/57 subjects would get emmetropia (66.67%) (P = 0.026). Conclusion: The IOL power calculation including both keratometry readings and surgically induced astigmatism seems to be more accurate and provides more precision in refractive prediction than classical calculation method.

Reflejo pupilar mesópico en pacientes tratados con fluoxetina / Mesopic pupillary reflex in patients treated with fluoxetine

INTRODUCCIÓN: Actualmente el tratamiento de enfermedades mentales mediante antidepresivos es muy frecuente. Los inhibidores selectivos de la recaptación de serotonina son los antidepresivos más prescritos a nivel mundial y han sido asociados con alteraciones en la acomodación o la pupila. El objetivo de este estudio es evaluar los efectos de la fluoxetina sobre el reflejo pupilar y la acomodación en población joven. METODOLOGÍA: El grupo de estudio contó con siete pacientes diagnosticados de depresión y tratados con fluoxetina; como grupo control se incluyeron 22 sujetos. Se evaluaron los reflejos pupilares y el estado acomodativo mediante el pupilómetro Power Refractor II. Se midieron 5 fases de 3 segundos cada una. En la fase 2 se produjo un deslumbramiento con una luz blanca. RESULTADOS: Para el diámetro pupilar se han obtenido valores máximos y mínimos mayores en el grupo de pacientes tratados con fluoxetina que en el control en todas las fases de medida. Para el grupo control se observa una contracción pupilar máxima en la fase de deslumbramiento, sin embargo, en el grupo de estudio se observa en la fase tras el deslumbramiento. En cuanto a la acomodación no se obtuvieron diferencias significativas entre ambos grupos. CONCLUSIONES: En pacientes tratados con fluoxetina existen alteraciones pupilares observándose diámetros pupilares mayores y menor velocidad de contracción pupilar. La falta de resultados concluyentes en cuanto a la acomodación no significa que no existan cambios relacionados con esta, cuya detección requerirá de futuros estudios utilizando diferentes metodologías y con un tamaño muestral mayor

INTRODUCTION: currently the treatment of mental illness by antidepressants is very frequent. Selective serotonin re-uptake inhibitors are the most prescribed antidepressants worldwide and have been associated with alterations in accommodation or pupil. The objective of this study is to evaluate the effects of fluoxetine on the pupillary reflex and the accommodation in young population. METHODOLOGY: The study group included seven patients diagnosed with depression and treated with fluoxetine; 22 subjects were included as a control group. The pupillary reflexes and the accommodative state were evaluated using the Power Refractor II pupilometer. Five phases of 3 seconds each were measured. In phase 2 there was a glare with a white light. RESULTS: For the pupil diameter, maximum and minimum values were obtained in the group of patients treated with fluoxetine than in the control in all the measurement phases. For the control group, a maximum pupillary contraction is observed in the glare phase, however, in the study group it is observed in the phase after glare. As for the accommodation, there are no significant differences between the two groups. CONCLUSIONS: In patients treated with fluoxetine there are pupillary alterations like a bigger pupillary diameters and slower pupillary contraction. The lack of conclusive results in terms of accommodation does not mean that there are no changes related to it, whose detection requires future studies with different methodologies and with a larger sample size

Visual Discrimination Increase by Yellow Filters in Retinitis Pigmentosa.

PURPOSE: The objective of this study was to evaluate, by halometry and under low illumination conditions, the effects of short-wavelength light absorbance filters on visual discrimination capacity in retinitis pigmentosa patients. METHODS: This was an observational, prospective, analytic, and transversal study on 109 eyes of 57 retinitis pigmentosa patients with visual acuity better than 1.25 logMAR. Visual disturbance index (VDI) was determined using the software Halo 1.0, with and without the interposition of filters which absorb (totally or partially) short-wavelength light between 380 and 500 nm. RESULTS: A statistically significant reduction in the VDI values determined using filters which absorb short-wavelength light was observed (p < 0.0001). The established VDIs in patients with VA logMAR <0.4 were 0.30 ± 0.05 (95% CI, 0.26-0.36) for the lens alone, 0.20 ± 0.04 (95% CI, 0.16-0.24) with the filter that completely absorbs wavelengths shorter than 450 nm, and 0.24 ± 0.04 (95% CI, 0.20-0.28) with the filter that partially absorbs wavelengths shorter than 450 nm, which implies a 20 to 33% visual discrimination capacity increase. In addition, a decrease of VDI in at least one eye was observed in more than 90% of patients when using a filter. CONCLUSIONS: Short-wavelength light absorbance filters increase visual discrimination capacity under low illumination conditions in retinitis pigmentosa patients. Use of such filters constitutes a suitable method to improve visual quality related to intraocular light visual disturbances under low illumination conditions in this group of patients.

Pupillary behavior in relation to wavelength and age.

Pupil light reflex can be used as a non-invasive ocular predictor of cephalic autonomic nervous system integrity. Spectral sensitivity of the pupil's response to light has, for some time, been an interesting issue. It has generally, however, only been investigated with the use of white light and studies with monochromatic wavelengths are scarce. This study investigates the effects of wavelength and age within three parameters of the pupil light reflex (amplitude of response, latency, and velocity of constriction) in a large sample of younger and older adults (N = 97), in mesopic conditions. Subjects were exposed to a single light stimulus at four different wavelengths: white (5600°K), blue (450 nm), green (510 nm), and red (600 nm). Data was analyzed appropriately, and, when applicable, using the General Linear Model (GLM), Randomized Complete Block Design (RCBD), Student's t-test and/or ANCOVA. Across all subjects, pupillary response to light had the greatest amplitude and shortest latency in white and green light conditions. In regards to age, older subjects (46-78 years) showed an increased latency in white light and decreased velocity of constriction in green light compared to younger subjects (18-45 years old). This study provides data patterns on parameters of wavelength-dependent pupil reflexes to light in adults and it contributes to the large body of pupillometric research. It is hoped that this study will add to the overall evaluation of cephalic autonomic nervous system integrity.

[Utility of dynamic pupillometry in alcohol testing on drivers]. / Utilidad de la pupilometría dinámica en el control de alcoholemia de los conductores.

Pupillometry is becoming a relevant tool in Vision Sciences. So far, only a few studies have explored the relationship between pupil reflex measures and drug consumption. The aim of this study was to assess the applicability of dynamic mesopic pupillometry as an objective measurement method for the detection of blood alcohol levels above the legal limit. In a quasiexperimental design, 19 volunteers were asked to participate in two conditions (before and after alcohol intake). In session with alcohol intake, participants were asked to consume 27.5 ml of alcohol in 60 minute intervals for four hours. Pupillometry records were conducted by means of the Power Refractor II, using four types of light stimulation: white (5600 K), blue (450 nm), green (510 nm) and red (600 nm). The basal diameter of the pupil increased significantly for alcohol concentrations equal to or greater than 0.25 mg/l in exhaled breath. Moreover, the value of the amplitude for red light constriction also provided significant differences between the two conditions. These results are promising in the search for new methods to detect illegal alcohol levels among drivers. This study demonstrates that basal pupil diameter increase and amplitude response could be used as an alcohol consumption level indicator. However, further studies are necessary to validate this and other diagnose methods complementary to breathalyzer and other drugs tests.

Utilidad de la pupilometría dinámica en el control de alcoholemia de los conductores / Utility of dynamic pupillometry in alcohol testing on drivers

La pupilometría se ha convertido en una herramienta de gran interés en las Ciencias de la Visión. Hasta el momento, solo unos pocos estudios han explorado la relación entre el reflejo pupilar y el consumo de drogas. El objetivo de este estudio fue evaluar la aplicabilidad de la pupilometría dinámica mesópica como método objetivo para la detección de niveles de alcoholemia por encima del límite legal. Se utilizó un diseño de carácter cuasi-experimental, con 19 voluntarios participando en dos condiciones (pre y post ingesta de alcohol). En la sesión con alcohol, los participantes consumieron 27.5 ml de alcohol en intervalos de 60 minutos durante 4 horas. Se llevaron a cabo registros de pupilometría mediante el Power Refractor II, utilizándose cuatro tipos de estimulación lumínica: blanca (5600 K), azul (450 nm), verde (510 nm) y roja (600 nm). El diámetro basal aumentó significativamente a partir de concentraciones de alcohol en aire espirado iguales o mayores de 0.25 mg/l. Además, el valor de la amplitud de constricción para la luz roja también ofreció diferencias significativas entre las dos condiciones. Estos resultados resultan prometedores en la búsqueda de nuevos métodos de detección de niveles de alcoholemia no permitidos al volante. En este estudio se demuestra que el incremento del diámetro basal y la amplitud pupilar pueden ser utilizados como indicador del nivel de consumo de alcohol. Son necesarios más estudios para validar éste y otros métodos de diagnóstico complementarios a las actuales pruebas de alcoholemia y de consumo de sustancias psicotropas (AU)

Pupillometry is becoming a relevant tool in Vision Sciences. So far, only a few studies have explored the relationship between pupil reflex measures and drug consumption. The aim of this study was to assess the applicability of dynamic mesopic pupillometry as an objective measurement method for the detection of blood alcohol levels above the legal limit. In a quasiexperimental design, 19 volunteers were asked to participate in two conditions (before and after alcohol intake). In session with alcohol intake, participants were asked to consume 27.5 ml of alcohol in 60 minute intervals for four hours. Pupillometry records were conducted by means of the Power Refractor II, using four types of light stimulation: white (5600 K), blue (450 nm), green (510 nm) and red (600 nm). The basal diameter of the pupil increased significantly for alcohol concentrations equal to or greater than 0.25 mg/l in exhaled breath. Moreover, the value of the amplitude for red light constriction also provided significant differences between the two conditions. These results are promising in the search for new methods to detect illegal alcohol levels among drivers. This study demonstrates that basal pupil diameter increase and amplitude response could be used as an alcohol consumption level indicator. However, further studies are necessary to validate this and other diagnose methods complementary to breathalyzer and other drugs tests (AU)

Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro.

Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.