Assessment of the Blue Light Ocular Hazard by Solar Measurements and the Impact of Selected Sunglasses Based upon the Limits of the International Commission on Non-Ionizing Radiation Protection Guideline.

ABSTRACT: A quantitative assessment of the blue light hazard for the human eye related to direct solar irradiation is presented. For six radiation situations, missing eye protection was compared to protection by nine different commercial sunglasses with and without an optimized blue light filter. Measurements of the solar irradiance were performed on Earth's surface as well as at an elevation of 12 km in the cockpit of an airliner. An irradiation time limit was calculated from the measurement data, within which the maximum blue light dose of 100 J m -2 , recommended by the International Commission on Non-Ionizing Radiation Protection and mandatory for the safe operation of lamps according to the norm ICE 62471, is reached. The results suggest that the blue light dose limit is violated within less than 3 s when looking without eye protection directly into the sun. For Category 3 sunglasses without the optimized blue light filter, time limits of 10 to 25 s on Earth's surface and 7 to 8 s at 12 km altitude were observed. The investigated Category 3 sunglasses with optimized blue light protection and suited for traffic use allow a time limit of more than 40 s on Earth's surface and 18 to 95 s in the airliner's cockpit. The outcome of the study is that the eye protection against blue light hazard related to solar radiation can be quantified using existing limits and that the choice of sunglasses is relevant: Traffic-worthy sunglasses optimized for protection against blue light hazard offer a better protection than non-optimized sunglasses.

Electron, Photon, and Neutron Dose Conversion Coefficients of Lens and Non-Lens Tissues Using a Multi-Tissue Eye Model to Assess Risk of Cataracts and Retinitis.

Previous publications describe the estimation of the dose from ionizing radiation to the whole lens or parts of it but have not considered other eye tissues that are implicated in cataract development; this is especially critical for low-dose, low-ionizing-density exposures. A recent review of the biological mechanisms of radiation-induced cataracts showed that lenticular oxidative stress can be increased by inflammation and vascular damage to non-lens tissues in the eye. Also, the radiation oxygen effect indicates different radiosensitivities for the vascular retina and the severely hypoxic lens. Therefore, this study uses the Monte Carlo N-Particle simulations to quantify dose conversion coefficients for several eye tissues for incident antero-posterior exposure to electrons, photons, and neutrons (and the tertiary electron component of neutron exposure). A stylized, multi-tissue eye model was developed by modifying a model by Behrens etal. (2009) to include the retina, uvea, sclera, and lens epithelial cell populations. Electron exposures were simulated as a single eye, whereas photon and neutron exposures were simulated employing two eyes embedded in the ADAM-EVA phantom. For electrons and photons, dose conversion coefficients are highest for either anterior tissues for low-energy incident particles or posterior tissues for high-energy incident particles. Neutron dose conversion coefficients generally increase with increasing incident energy for all tissues. The ratio of the absorbed dose delivered to each tissue to the absorbed dose delivered to the whole lens demonstrated the considerable deviation of non-lens tissue doses from lens doses, depending on particle type and its energy. These simulations demonstrate that there are large variations in the dose to various ocular tissues depending on the incident radiation dose coefficients; this large variation will potentially impact cataract development.

Hydrogen nanobubbles: A novel approach toward radio-sensitization agents.

BACKGROUND: Ocular melanoma is a rare kind of eye malignancy that threatens the patient's eyesight. Radiotherapy and surgical removal are the most commonly used therapeutic modalities, and nanomedicine has lately entered this field. Brachytherapy using Ruthenium-106 (106 Ru) ophthalmic plaques has been used for decades to treat ocular melanoma, with the applicator placed on the patient's eyes until the prescribed dose reaches the tumor apex. PURPOSE: To investigate the efficiency of hydrogen nanobubbles (H2 -NBs) employment during intraocular melanoma brachytherapy using a 106 Ru electron emitter plaque. METHODS: The Monte Carlo (MC) simulation and experimental investigation using a 3D-designed phantom and thermoluminescence dosimetry (TLD) were employed. Various concentrations of H2 -NBs with a diameter of 100 nm were simulated inside tumor tissue. The results were presented as deposited energy and dose enhancement factor (DEF). An equivalent Resin phantom of the human eyeball was made using AutoCAD and 3D-Printer technologies. The glass-bead TLDs dosimeter were employed and placed inside the phantom. RESULTS: Using a 1% concentration of H2 -NBs, a DEF of 93% and 98% were achieved at the tumor apex of 10 mm from the experimental setup and MC simulation, respectively. For simulated concentrations of 0.1%, 0.3%, 0.5%, 1%, and 4% H2 -NBs, a maximum dose enhancement of 154%, 174%, 188%, 200%, and 300% were achieved, respectively, and a dose reduction was seen at about 3 mm from the plaque surface. CONCLUSION: H2 -NBs can be used as an absorbed dose enhancer in 106 Ru eye brachytherapy because of their unique physical characteristics. Reducing plaque implantation time on the patient's eye, reducing sclera absorbed dose, and decreasing the risk of patients' healthy organs irradiation are reported as some of the potential benefits of using H2-NBs.

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C (UV-C) Damage.

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational health hazard. Here, we demonstrate the exposure of primary stem cells from the mouse ocular surface to UV-C radiation. Reactive oxygen species (ROS) formation is the readout of the extent of oxidative stress/damage. In an experimental in vitro setting, it is also essential to assess the percentage of dead cells generated due to oxidative stress. In this article, we will demonstrate the 2',7'-Dichlorofluoresceindiacetate (DCFDA) staining of UV-C exposed mouse primary ocular surface stem cells and their quantification based on the fluorescent images of DCFDA staining. DCFDA staining directly corresponds to ROS generation. We also demonstrate the quantification of dead and live cells by simultaneous staining with propidium iodide (PI) and Hoechst 3332 respectively and the percentage of DCFDA (ROS positive) and PI positive cells.

Investigation of gold nanoparticle effects in brachytherapy by an electron emitter ophthalmic plaque.

Background: During decades, all improvements and developments in radiation therapy technologies have been focused on its main goal: maximize the dose in the tumor and minimize it in surrounding normal tissues. Recently, scientists have some approaches to nanoparticles, especially gold nanoparticles (GNPs), for dose localization. Purpose: Herein, the effect of GNPs in combination with electron brachytherapy in a model of eye tumor has been investigated. Materials and methods: Monte Carlo simulation was utilized and a complete anatomical model of the eye, a tumor with 5 mm thick, and a type of Ruthenium-106 beta emitter ophthalmic plaque were simulated. Simulation results have been validated by a Plexiglas eye phantom and film dosimetry, experimentally. Results: The results showed using GNPs causes the dose amplification in 2 mm from the plaque surface which the higher concentration has the higher enhancement. At more distances, Dose Enhancement Factors (DEFs) have the negative amounts, so that total delivered dose to the tumor has decreased with increasing of Au concentrations and the dose of organ at risk like sclera has increased. Conclusion: Therefore, using of GNPs along with a 106Ru/106Rh ocular plaque, as an electron emitter source, is a good choice only for superficial lesions, and it is not recommended for deeper tumors due to the parameters of radiation treatment and delivered dose to the tissues.

Dosimetric dependence of ocular structures on eye size and shape for external radiation fields of electrons, photons, and neutrons.

The dosimetric dependence of ocular structures on eye size and shape was investigated within the standard ICRP Publication 116 irradiation geometries. A realistic transport geometry was constructed by inserting a scalable and deformable stylised eye model developed in our previous study within the head of the ICRP Publication 110 adult male reference computational phantom. Beam irradiations of external electrons, photons, and neutrons on this phantom were simulated using the Monte Carlo radiation transport code PHITS in the geometries of AP, RLAT, PA and ROT. Absorbed doses in ocular structures such as ciliary body, retina, and optic nerves were computed as well as that in lens. A clear dosimetric dependence of ocular structures on eye size and shape was observed for external electrons while only a small dependence was seen for external photons and neutrons. Difference of the tendency was attributed to their depth-dose distributions where spread dose distributions were created by photons and neutrons while more concentrated distributions were created by external electrons.

Construction and evaluation of a real-time personal dosemeter based on a Si sensor for eye-dose measurement.

The objective was to design a thin, flex card based personal dosemeter with low angular and energy dependence. It is based on silicon diodes that can measure the personal dose equivalent. Anisotropic conducting adhesive was used to connect the Si sensor to the flex card. Its intended use is for interventional radiology and after nuclear or radiological accidents, as it provides immediate detailed information about the dose rate to the wearer during shorter periods and integrates the dose rate during hours. It can be freely placed all over the body. By placing the dosemeter close to the eyes, it may be possible to estimate the personal dose equivalent as well as the dose at the lens of the eye.

LEDs for photons, physiology and food.

Lighting based on light-emitting diodes (LEDs) not only is more energy efficient than traditional lighting, but also enables improved performance and control. The colour, intensity and distribution of light can now be controlled with unprecedented precision, enabling light to be used both as a signal for specific physiological responses in humans and plants, and as an efficient fuel for fresh food production. Here we show how a broad and improved understanding of the physiological responses to light will facilitate greater energy savings and provide health and productivity benefits that have not previously been associated with lighting.

Dosimetric comparison between realistic ocular model and other models for COMS plaque brachytherapy with 103Pd, 131Cs, and 125I radioisotopes.

Nowadays, Monte Carlo calculations are commonly used for the evaluation of dose distributions and dose volume histograms in eye brachytherapy. However, currently available eye models have simple geometries, and main substructures of the eye are either not defined in details or not distinguished at all. In this work absorbed doses of eye substructures have been estimated for eye plaque brachytherapy using the most realistic eye model available, and compared with absorbed doses obtained with other available eye models. For this, a medium-sized tumour on the left sides of the right eye was considered. Dosimetry calculations were performed for four different eye models developed based on a literature review, and using a 12 mm Collaborative Ocular Melanoma Study plaque containing 131Cs, 103Pd, and 125I sources. Obtained results illustrate that the estimated doses received by different eye substructures strongly depend on the model used to represent the eye. It is shown here that using a non-realistic eye model leads to a wrong estimation of doses for some eye substructures. For example, dose differences of up to 35% were observed between the models proposed by Nogueira and co-workers and Yoriyaz and co-workers, while doses obtained by use of the models proposed by Lesperance and co-workers, and Behrens and co-workers differed up to 100 and 63% as compared to the situation when a realistic model was used, respectively. Moreover, comparing different radionuclides showed that the most uniform dose distribution in the considered tumour region was that from 131Cs, with a coefficient of variation of 33%. In addition, considering the realistic eye model, it was found that the radiosensitive region of the lens received more than the threshold dose of cataract induction (0.5 Gy), for all investigated radionuclides.

Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I-125 seeds.

PURPOSE: To investigate the dose calculation accuracy of the Advanced Collapsed cone Engine (ACE) algorithm for ocular brachytherapy using a COMS plaque loaded with I-125 seeds for two heterogeneous patient tissue scenarios. METHODS: The Oncura model 6711 I-125 seed and 16 mm COMS plaque were added to a research version (v4.6) of the Oncentra® Brachy (OcB) treatment planning system (TPS) for dose calculations using ACE. Treatment plans were created for two heterogeneous cases: (a) a voxelized eye phantom comprising realistic eye materials and densities and (b) a patient CT dataset with variable densities throughout the dataset. ACE dose calculations were performed using a high accuracy mode, high-resolution calculation grid matching the imported CT datasets (0.5 × 0.5 × 0.5 mm3 ), and a user-defined CT calibration curve. The accuracy of ACE was evaluated by replicating the plan geometries and comparing to Monte Carlo (MC) calculated doses obtained using MCNP6. The effects of the heterogeneous patient tissues on the dose distributions were also evaluated by performing the ACE and MCNP6 calculations for the same scenarios but setting all tissues and air to water. RESULTS: Average local percent dose differences between ACE and MC within contoured structures and at points of interest for both scenarios ranged from 1.2% to 20.9%, and along the plaque central axis (CAX) from 0.7% to 7.8%. The largest differences occurred in the plaque penumbra (up to 17%), and at contoured structure interfaces (up to 20%). Other regions in the eye agreed more closely, within the uncertainties of ACE dose calculations (~5%). Compared to that, dose differences between water-based and fully heterogeneous tissue simulations were up to 27%. CONCLUSIONS: Overall, ACE dosimetry agreed well with MC in the tumor volume and along the plaque CAX for the two heterogeneous tissue scenarios, indicating that ACE could potentially be used for clinical ocular brachytherapy dosimetry. In general, ACE data matched the fully heterogeneous MC data more closely than water-based data, even in regions where the ACE accuracy was relatively low. However, depending on the plaque position, doses to critical structures near the plaque penumbra or at tissue interfaces were less accurate, indicating that improvements may be necessary. More extensive knowledge of eye tissue compositions is still required.

Absorbed dose distributions from ophthalmic 106 Ru/106 Rh plaques measured in water with radiochromic film.

PURPOSE: Brachytherapy with 106 Ru/106 Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of 106 Ru/106 Rh plaques used solid phantoms. This work aims to develop a practical method for measuring the absorbed dose distribution in water produced by 106 Ru/106 Rh plaques using EBT3 radiochromic film. METHODS: Experimental setups were developed to determine the dose distribution at a plane perpendicular to the symmetry axis of the plaque and at a plane containing the symmetry axis. One CCA and two CCX plaques were studied. The dose maps were obtained with the FilmQA Pro 2015 software, using the triple-channel dosimetry method. The measured dose distributions were compared to published Monte Carlo simulation and experimental data. RESULTS: A good agreement was found between measurements and simulations, improving upon published data. Measured reference dose rates agreed within the experimental uncertainty with data obtained by the manufacturer using a scintillation detector, with typical differences below 5%. The attained experimental uncertainty was 4.1% (k = 1) for the perpendicular setup, and 7.9% (k = 1) for the parallel setup. These values are similar or smaller than those obtained by the manufacturer and other authors, without the need of solid phantoms that are not available to most users. CONCLUSIONS: The proposed method may be useful to the users to perform quality assurance preclinical tests of 106 Ru/106 Rh plaques.

IMAGING OF PROTON BRAGG PEAKS IN LiF.

Lithium fluoride (LiF) is one of the most common thermoluminescent phosphors routinely used in radiation protection services. Another advantageous property of LiF is radiophotoluminescence, whose occurs after its irradiation due to the creation of color centers. Excitation of LiF samples with a blue light causes the emission of photoluminescence, which spectrum consists of two peaks at ~520 and ~670 nm. The work was focused on imaging of Bragg peaks of proton beams routinely applied at the proton eye radiotherapy facility operating at the Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN) in Krakow by the measurement of the fluorescence light in LiF crystals excited with a 445 nm blue light after their previous irradiation with the proton beams of energies of 28, 30, 40 and 50 MeV. The range of proton beams in LiF crystals for different energies was calculated by Monte Carlo simulations.

Technical Note: Dosimetric characteristics of the ocular beam line and commissioning data for an ocular proton therapy planning system at the Proton Therapy Center Houston.

PURPOSE: To systematically analyze and present the properties of a small-field, double-scattering proton beam line intended to be used for the treatment of ocular cancer, and to provide configuration data for commission of the Eclipse Ocular Proton Planning System. METHODS: Measurements were made using ionization chambers, diodes, and films to determine dose profiles and output factors of the proton beams of the beam line at the Proton Therapy Center Houston. In parallel, Monte Carlo simulations were performed to validate the measured data and to provide additional insight into detailed beam parameters that are hard to measure, such as field size factors and a comparison of output factors as a function of circular and rectangular fields. RESULTS: The presented data comprise depth dose profiles, including distal and proximal profiles used to configure the Eclipse Ocular Proton Planning system, distal fall-off widths, lateral profiles and penumbrae sizes, as well as output factors as a function of field size, SOBP width, range shifter thickness, snout position, and source-to-surface distance. CONCLUSIONS: We have completed a comprehensive characterization of the beam line. The data will be useful to characterize proton beams in clinical and experimental small-field applications.

Monte Carlo Simulation Used to Calculate Energy Correction Factor for Thermoluminescent Dosimeters Used by Occupational Workers on Pediatric Exams.

The main objective of this work is to simulate the X-ray scattered spectra by different pediatric phantoms (simulation of children subjected to barium meal procedures) to calculate an energy correction factor (ECF) to the reading of thermoluminescent dosimeters (TLDs). To perform this evaluation, the TLDs were positioned over three areas in two occupational workers: eyes, thyroid and hands. The Geant4 toolkit was used to define the spectra collected by TLDs, making possible to calculate the ECF. This work was developed in two stages: (1) evaluation of scattered spectra by different standard phantoms (newborn, 1, 5 and 10 years old); (2) definition of the ECF to the absorbed energy by each TLD. Geant4 shows to be a good toolkit to calculate the ECF and among the different characteristics evaluated, in this work, the TLD position and acceleration voltages are the most significant parameters that may influence the ECF calculated.

Comparison between beta radiation dose distribution due to LDR and HDR ocular brachytherapy applicators using GATE Monte Carlo platform.

Eye applicators with 90Sr/90Y and 106Ru/106Rh beta-ray sources are generally used in brachytherapy for the treatment of eye diseases as uveal melanoma. Whenever, radiation is used in treatment, dosimetry is essential. However, knowledge of the exact dose distribution is a critical decision-making to the outcome of the treatment. The Monte Carlo technique provides a powerful tool for calculation of the dose and dose distributions which helps to predict and determine the doses from different shapes of various types of eye applicators more accurately. The aim of this work consisted in using the Monte Carlo GATE platform to calculate the 3D dose distribution on a mathematical model of the human eye according to international recommendations. Mathematical models were developed for four ophthalmic applicators, two HDR 90Sr applicators SIA.20 and SIA.6, and two LDR 106Ru applicators, a concave CCB model and a flat CCB model. In present work, considering a heterogeneous eye phantom and the chosen tumor, obtained results with the use of GATE for mean doses distributions in a phantom and according to international recommendations show a discrepancy with respect to those specified by the manufacturers. The QC of dosimetric parameters shows that contrarily to the other applicators, the SIA.20 applicator is consistent with recommendations. The GATE platform show that the SIA.20 applicator present better results, namely the dose delivered to critical structures were lower compared to those obtained for the other applicators, and the SIA.6 applicator, simulated with MCNPX generates higher lens doses than those generated by GATE.

Kilovoltage radiosurgery with gold nanoparticles for neovascular age-related macular degeneration (AMD): a Monte Carlo evaluation.

This work uses Monte Carlo radiation transport simulation to assess the potential benefits of gold nanoparticles (AuNP) in the treatment of neovascular age-related macular degeneration with stereotactic radiosurgery. Clinically, a 100 kVp x-ray beam of 4 mm diameter is aimed at the macula to deliver an ablative dose in a single fraction. In the transport model, AuNP accumulated at the bottom of the macula are targeted with a source representative of the clinical beam in order to provide enhanced dose to the diseased macular endothelial cells. It is observed that, because of the AuNP, the dose to the endothelial cells can be significantly enhanced, allowing for greater sparing of optic nerve, retina and other neighboring healthy tissue. For 20 nm diameter AuNP concentration of 32 mg g(-1), which has been shown to be achievable in vivo, a dose enhancement ratio (DER) of 1.97 was found to be possible, which could potentially be increased through appropriate optimization of beam quality and/or AuNP targeting. A significant enhancement in dose is seen in the vicinity of the AuNP layer within 30 µm, peaked at the AuNP-tissue interface. Different angular tilting of the 4 mm beam results in a similar enhancement. The DER inside and in the penumbra of the 4 mm irradiation-field are almost the same while the actual delivered dose is more than one order of magnitude lower outside the field leading to normal tissue sparing. The prescribed dose to macular endothelial cells can be delivered using almost half of the radiation allowing reduction of dose to the neighboring organs such as retina/optic nerve by 49% when compared to a treatment without AuNP.

Experimental depth dose curves of a 67.5 MeV proton beam for benchmarking and validation of Monte Carlo simulation.

PURPOSE: To measure depth dose curves for a 67.5 ± 0.1 MeV proton beam for benchmarking and validation of Monte Carlo simulation. METHODS: Depth dose curves were measured in 2 beam lines. Protons in the raw beam line traversed a Ta scattering foil, 0.1016 or 0.381 mm thick, a secondary emission monitor comprised of thin Al foils, and a thin Kapton exit window. The beam energy and peak width and the composition and density of material traversed by the beam were known with sufficient accuracy to permit benchmark quality measurements. Diodes for charged particle dosimetry from two different manufacturers were used to scan the depth dose curves with 0.003 mm depth reproducibility in a water tank placed 300 mm from the exit window. Depth in water was determined with an uncertainty of 0.15 mm, including the uncertainty in the water equivalent depth of the sensitive volume of the detector. Parallel-plate chambers were used to verify the accuracy of the shape of the Bragg peak and the peak-to-plateau ratio measured with the diodes. The uncertainty in the measured peak-to-plateau ratio was 4%. Depth dose curves were also measured with a diode for a Bragg curve and treatment beam spread out Bragg peak (SOBP) on the beam line used for eye treatment. The measurements were compared to Monte Carlo simulation done with geant4 using topas. RESULTS: The 80% dose at the distal side of the Bragg peak for the thinner foil was at 37.47 ± 0.11 mm (average of measurement with diodes from two different manufacturers), compared to the simulated value of 37.20 mm. The 80% dose for the thicker foil was at 35.08 ± 0.15 mm, compared to the simulated value of 34.90 mm. The measured peak-to-plateau ratio was within one standard deviation experimental uncertainty of the simulated result for the thinnest foil and two standard deviations for the thickest foil. It was necessary to include the collimation in the simulation, which had a more pronounced effect on the peak-to-plateau ratio for the thicker foil. The treatment beam, being unfocussed, had a broader Bragg peak than the raw beam. A 1.3 ± 0.1 MeV FWHM peak width in the energy distribution was used in the simulation to match the Bragg peak width. An additional 1.3-2.24 mm of water in the water column was required over the nominal values to match the measured depth penetration. CONCLUSIONS: The proton Bragg curve measured for the 0.1016 mm thick Ta foil provided the most accurate benchmark, having a low contribution of proton scatter from upstream of the water tank. The accuracy was 0.15% in measured beam energy and 0.3% in measured depth penetration at the Bragg peak. The depth of the distal edge of the Bragg peak in the simulation fell short of measurement, suggesting that the mean ionization potential of water is 2-5 eV higher than the 78 eV used in the stopping power calculation for the simulation. The eye treatment beam line depth dose curves provide validation of Monte Carlo simulation of a Bragg curve and SOBP with 4%/2 mm accuracy.

Assessment of 8-methosypsoralen, lomefloxacin, sparfloxacin, and Pirfenidone phototoxicity in Long-Evans rats.

Phototoxicity has a strong impact on drug development. Although several animal models have been developed to quantitatively assess human risks, none have been validated for standardized use. In this study, we validated an in vivo phototoxicity model using Long-Evans (LE) rats treated with 4 well-known phototoxic drugs, namely 8-methoxypsoralen, lomefloxacin, sparfloxacin, and pirfenidone. Daily macroscopic observations of skin and eyes, ophthalmological examinations 4 days after dosing, and blood sampling for toxicokinetics (TKs) were performed after exposure of treated animals to ultraviolet, and dose-dependent eye and/or skin reactions were noted for all compounds. Margins of safety were calculated when possible and correlated well with known relative phototoxicity of the 4 compounds. We conclude that the present in vivo phototoxicity assay using LE rats with TK analysis can be used to quantitatively predict the risk of pharmaceutical phototoxicity in humans.

Assessment of the radiological safety of a Genoray portable dental X-ray unit.

OBJECTIVES: The portable dental radiographic systems are generally used in emergency situations (e.g. during natural disasters) for disabled/aged patients and in patient rooms. This study assesses the output exposure of a portable dental radiographic system measured using thermoluminescent dosemeters (TLDs). METHODS: Occupational exposure of the operator was determined when the portable dental unit was used for mandibular and maxillary teeth exposure. RESULTS: The doses of some critical organs of an operator were measured using TLDs implanted within the Rando phantom. CONCLUSIONS: Considering the annual organ dose limits, the eye lens dose limit is the main factor determining the frequency of system application.

Contribution to the radiation protection for sunglasses standards.

Literature establishes safe limits on the exposure of the eyes to ultraviolet radiation, for the range of 180-400 nm, including spectrally weighted and the total ultraviolet radiant exposure. Most standards for sunglasses protection only require ultraviolet protection in the spectral range of 280-380 nm to ensure the limits for effective spectrally weighted radiant exposure. Calculations of these limits were performed for 27 Brazilian state capitals, and they led to a change in the upper UVA limit to 400 nm on the 2013 review of the Brazilian standard. Moreover, because the sunlight irradiance in Brazil is quite high, integration over the 280- to 400-nm range yields an ultraviolet radiant exposure that is an average of 49% greater than that for the 280- to 380-nm range. These conclusions suggest revision on the standards.