Blue Light Phototherapy Research Articles

A new targeted blue light phototherapy for the treatment of acne

The effects of blue light phototherapy on inflammatory acne lesions were recently investigated. Many reports have used high-intensity, narrow-band 420 nm UV-free blue light delivery systems. The aim of this study was to evaluate a new blue light system (MultiClear) for targeted blue light phototherapy. Ten Japanese patients with acne on the face or back were treated with targeted blue light once or twice a week. Acne severity was graded according to the acne severity score suggested by Allen and Smith (1982). If the acne was prevalent on the back or chest, the acne severity score of Burton et al. (1971) was adopted. The new targeting blue light system is equipped with a flexible optical light guide as a delivery system and the treatment device is placed directly only on the affected area. Of the 10 patients, eight had a significantly reduced acne severity score without any side effects. Although two patients discontinued the study because of unsatisfactory results, none of the patients showed any harmful side effects from the targeted blue light phototherapy. Targeted blue light phototherapy with MultiClear is effective for the treatment of inflammatory acne lesions. This new irradiation device offers some advantages over previous blue light systems.

The Effect of Blue Light Exposure on the Expression of Circadian Genes: Bmal1 and Cryptochrome 1 in Peripheral Blood Mononuclear Cells of Jaundiced Neonates

The purpose of this study was to investigate the effect of blue light phototherapy on the expression of circadian genes in peripheral blood mononuclear cells (PBMC) and plasma melatonin levels in neonates. Real-time reverse-transcriptase polymerase chain reaction (RT-PCR) was used to determine the expression of Bmal1 and Cry1 in PBMC, and an enzyme-linked immunosorbent assay was used to determine plasma melatonin levels in 32 breast-milk jaundiced neonates before and after phototherapy, compared with 29 control neonates. The results showed that the expression of Bmal1 was decreased and Cry1 increased significantly after phototherapy. Plasma melatonin levels were decreased after phototherapy. There was no statistical difference in Bmal1 and Cry1 gene expression and plasma melatonin levels in the control group. In conclusion, phototherapy does affect the expression of the circadian genes Bmal1 and Cry1 in PBMC and plasma melatonin concentration in jaundiced neonates. Our results suggest that phototherapy should be timed according to circadian rhythms when treating jaundiced neonates.

Phototherapy: Old questions, new answers

Despite its popularity and widespread use, there remains much more to be learned about phototherapy. There is continued debate on whether intermittent phototherapy is more effective than continuous phototherapy; if light of a longer wavelength is more effective than blue light phototherapy; and if phototherapy in the presence of bilirubin is toxic to normal or abnormal red blood cells. Three in vitro studies in this issue of the journal provide answers to some of these questions.

Use of daytime phototherapy for Crigler–Najjar disease

Crigler-Najjar syndrome type 1 (CNS1) is characterized by a severe unconjugated hyperbilirubinemia from birth. Intensive blue-light phototherapy is the standard method for management; however, it imposes severe restrictions on the child and their family's lifestyle. We describe here the use of a novel sit-up phototherapy unit in a child with CNS1. The unit allowed a 50% reduction in phototherapy time while maintaining efficacy, thus enabling the child to attend school.

An open study to determine the efficacy of blue light in the treatment of mild to moderate acne

Background: The effective management of acne remains a challenge; achieving an optimal response whilst minimizing adverse events is often difficult. The rise in antibiotic resistance threatens to reduce the future usefulness of the current mainstay of therapy. The need for alternative therapies remains important. Phototherapy has previously been shown to be effective in acne, with renewed interest as both endogenous and exogenous photodynamic therapies are demonstrated for this condition. Objectives: To determine the effect of narrowband blue light in the reduction of inflammatory and non‐inflammatory lesions in patients with mild to moderate acne and to evaluate patient tolerance of the therapy. Methods: We performed an open study utilizing a blue LED light source in 30 subjects with mild to moderate facial acne. Two weeks after screening, lesions were counted and recorded by lesion type. Over 4 weeks, patients received eight 10‐ or 20‐minute light treatments, peak wavelength 409–419 nm at 40 mW/cm2. Assessments were taken at weeks 5, 8 and 12 and lesion counts were recorded. Repeated measures‐ANOVA and Dunnett's tests, respectively, allowed assessment of the different scores over time and permitted comparison of mean counts. Results: An overall effect on inflammatory counts was observed at week 5, and a statistically significant decrease in inflamed counts was detected at the week 8 assessments, which continued to week 12. There was little effect on non‐inflamed lesions. The treatment was well tolerated with adverse events experienced generally rated as being mild and usually self‐limiting. Conclusions: Eight 10‐ or 20‐minute treatments over 4 weeks with a narrowband blue light was found to be effective in reducing the number of inflamed lesions in subjects with mild to moderate acne. The treatment had little effect on the number of comedones. The onset of the effect was observable at the first assessment, at week 5, and maximal between weeks 8 and 12. Blue light phototherapy using a narrowband LED light source appears to be a safe and effective additional therapy for mild to moderate acne.

Do phototherapy hoods really protect the neonate?

The objective of the current study was to evaluate the protection given to the eyes of neonates by an Amber 300 phototherapy hood during blue-light phototherapy from Drager Phototherapie 800 units, and to make recommendations for clinical practice. Hazard-weighted blue-light radiance of phototherapy lamps was measured inside neonatal incubators, with and without the use of a protective phototherapy hood. The study was carried out in a tertiary referral neonatal unit. No patients were involved. A mannequin was used as model of a jaundiced neonate being treated with blue-light phototherapy. The study shows that hazard-weighted blue-light radiance levels detectable from within the space enclosed by the hood may be several times greater than accepted industrial threshold limits for adults. Nursing and medical staff must ensure meticulous care in the positioning of infants, so that the caudal edge of the shadow cast by the hood is always at least 30 mm inferior to the infants' lower eyelids. The vulnerability of the neonatal retina and the relatively high levels of blue-light radiance visible from within the shadow of the hood may make it advisable to use more effective eye protection. Triple phototherapy using lamps at the foot-end of the incubator is clearly hazardous and should not be carried out unless the infant's eyes are protected by eye-patches.

Comparison of the efficacy of conventional special blue light phototherapy and fiberoptic phototherapy in the management of neonatal hyperbilirubinaemia

The efficacy and usefulness of two types of phototherapy differing in the source, wavelength and irradiance of the light, conventional phototherapy consisting of special blue light and fiberoptic phototherapy, were compared in a relatively larger series of term newborns with non‐haemolytic and more significant hyperbilirubinaemia than those in previous studies. In total, 108 newborns were allocated sequentially to receive either conventional phototherapy consisting of five special blue lamps or fiberoptic phototherapy. The average spectral irradiance measured at the skin surface level of newborns during the study period was significantly greater in the conventional phototherapy group. The special blue lamp of the conventional phototherapy unit had an emission spectrum almost identical to the bilirubin absorption spectrum, whereas the tungsten‐halogen lamp of the fiberoptic phototherapy had a broad emission through the blue and green wavelengths (mainly in the green spectrum). Phototherapy was more effective in the conventional phototherapy group; the duration of exposure to phototherapy (h) was significantly shorter, and the overall bilirubin decline rate (as μmol/l/h and %/h) was significantly greater in the conventional phototherapy group. According to the nursing personnel, fiberoptic phototherapy was more comfortable than the conventional phototherapy frame because of the easier accessibility and handling of the infants during phototherapy. They complained of giddiness, nausea, glare, temporary blurring of vision and difficulty in detecting the skin colour changes of newborns with the blue light of the conventional phototherapy unit. Conventional phototherapy consisting of special blue fluorescent lamps with approximately twofold higher irradiance and an emission spectrum almost identical to the bilirubin absorption spectrum is preferable to fiberoptic phototherapy in the standard treatment of term newborns with non‐haemolytic hyperbilirubinaemia.

The effect of phototherapy on cerebral blood flow velocity in preterm infants.

Cerebral blood flow velocity was studied with two-dimensional/pulsed Doppler ultrasound before, during and after discontinuation of phototherapy in 22 preterm infants (gestational age < or =32 weeks), who were treated for a minimum of 12h with blue-light phototherapy for non-haemolytic hyperbilirubinaemia. Before the cerebral blood flow velocity measurements, patency of the ductus arteriosus was diagnosed by Doppler echocardiography. All infants had normal brain ultrasound scans. Mean cerebral blood flow velocity increased significantly after initiation of phototherapy in all infants. Only in "healthy" (non-ventilated) infants did cerebral blood flow velocity return to pre-phototherapy values (baseline) after discontinuation of phototherapy, whereas in "unhealthy" (ventilated) infants cerebral blood flow velocity did not return to baseline. In 10 infants the ductus arteriosus reopened during phototherapy. In those infants, mean cerebral blood flow velocity returned to pre-phototherapy values after 2 h of phototherapy prior to its discontinuation.

Improvements in long term phototherapy for patients with Crigler - Najjar syndrome Type I

Patients with Crigler - Najjar syndrome Type I are being treated with long-term blue-light phototherapy into childhood, adolescence and beyond. Phototherapy systems adapted from sunbed-type bases fitted with blue-emitting fluorescent tubes have been described. These systems provide higher irradiances and improved patient compliance compared with overhead therapy systems used in neonatal phototherapy. The acrylic bases of such units are, however, not designed to provide adequate levels of comfort for prolonged treatment in the long term. Previous work has shown that layer(s) of transparent `bubble-wrap' can be used to address this problem, although the material absorbs light and provides lower levels of comfort for older or larger patients. We have used designs of transparent plastic lilos that provide better cushioning, although tend to puncture, and share with bubble-wrap a low porosity leading to patient discomfort. We have investigated the use of standard mesh and high-transmission fabrics stretched over an adjustable-tension frame. This method in particular combines a high degree of comfort with a clinically effective blue-light irradiance level, and hence appears to provide a satisfactory method of phototherapy delivery. The development of higher transmission materials offers further potential for improvement.

Clinical usefulness of high intensity green light phototherapy in the treatment of neonatal jaundice

Two matched groups of term newborn infants with idiopathic jaundice were subjected to intensive double direction green or blue light phototherapy (PT). The efficacy of treatment was expressed as rate of decline of serum bilirubin concentration after 6, 12 and 24 h of light exposure. More rapid response was obtained using conventional blue lamps (Philips TL/20W/52) than green lamps (Sylvania F20T12/G). Whole duration of PT was significantly shorter using blue lamps (P less than 0.05). However, less postphototherapy rebound was observed in babies treated with green light PT. It can be concluded that green light PT is useful but not preferable to blue light PT for clinical use in the treatment of neonatal jaundice.

Does Non-ionizing Radiant Energy Affect Determination of the Evaporation Rate by the Gradient Method?

A study was performed to investigate whether measurements of the evaporation rate from the skin of newborn infants by the gradient method are affected by the presence of non-ionizing radiation from phototherapy equipment or a radiant heater. The evaporation rate was measured experimentally with the measuring sensors either exposed to or protected from non-ionizing radiation. Either blue light (phototherapy) or infrared light (radiant heater) was used; in the former case the evaporation rate was measured from a beaker of water covered with a semipermeable membrane, and in the latter case from the hand of an adult subject, aluminium foil or with the measuring probe in the air. No adverse effect on the determinations of the evaporation rate was found in the presence of blue light. Infrared radiation caused an error of 0.8 g/m2h when the radiant heater was set at its highest effect level or when the ambient humidity was high. At low and moderate levels the observed evaporation rate was not affected. It is concluded that when clinical measurements are made from the skin of newborn infants nursed under a radiant heater, the evaporation rate can appropriately be determined by the gradient method.

Cerebral Hemodynamics in Low-Birth-Weight Infants Treated with Phototherapy

Changes of cerebral blood flow were determined in 20 preterm infants undergoing blue-light phototherapy for hyperbilirubinemia. All were healthy very-low-birth-weight infants (less than 1,500 g) with normal brain sonograms and not under pharmacological treatment at the time of the investigation. Blood flow velocity (pulsatility index and area under velocity curve) was measured by Duplex Scan technique during and after phototherapy. No changes of global cerebral blood flow were observed in the anterior cerebral artery (p less than 0.5). Our results suggest no functional disturbance of cerebral autoregulation in low-birth-weight infants treated with phototherapy.

102: SLOW EXCRETION OF THE 4Z, I5E‐BILIRUBIN CONFIGURATIONAL ISOMER DURING PHOTOTHERAPY FOR CRIGLER NAJJAR SYNDROME

Phototherapy (PT) is the only treatment of value in the long-term management of Crigler–Najjar syndrome type I (C-N.s.). At present (Proc.Natl.Acad.Sci.USA 78:1882, (1981)) it seems that the formation and elimination of the 4Z,15E-bilirubin configurational isomer (Z,E) is the major contributor in lowering bilirubin (BR) levels during PT for C-N.S.. TO verify this hypotesis, we have analyzed the serum BR isomer composition of a 15-years-old girl with C-N.s. during PT by HPLC method. We used green (Sylvania F20T12/G) and ‘special’ blue (Philips F20T12/BB) fluorescent lamps because of their different capacity to produce Z,E isomer. We report the steady-state serum concentrations of Z,E with either green and ‘special’ blue PT. The excretory rate for the Z,E isomer was estimated by measuring the Z,E concentration at the cessation of PT and after 2 hours (patient kept under red light). Our result show that during the 2 hours period following the interruption of both green and ‘special’ blue PT the absolute serum amount of Z,E remains nearly constant. Moreover, before the beginning of PT, the patient had a significant serum level of the Z,E isomer (13.2% ± .2%) due to the blue light PT administered 12 hours before. These evidences show that in this patient the disappearance rate of Z,E isomer is too slow to account for the total BR excretion during PT.

Green light phototherapy in newborninfants with ABO hemolytic disease

The efficacy of fluorescent green light phototherapy was compared with that of blue light phototherapy in the treatment of full-term infants with hemolytic disease and jaundice caused by ABO incompatibility. The efficacy of the treatment was expressed as actual (milligrams per hour) and quantum (milligrams per hour per square centimeter per megawatt) efficiency, taking into account the differential emission of energy from the green versus the blue fluorescent tubes. No statistically significant difference in the rate of serum bilirubin photodegradation was found between the two groups after treatment for 84.6 +/- 14.1 hours versus 81.5 +/- 14.2 hours with the green and the blue phototherapy, respectively. These results, coupled with the known effects of the blue light on the genetic apparatus of mammalian cells, support the application of the green light phototherapy for the treatment of neonatal hyperbilirubinemia caused by ABO incompatibility.

Stability of dopamine hydrochloride exposed to blue-light phototherapy

The stability of dopamine hydrochloride in 5% dextrose injection when exposed to blue-light phototherapy was assessed. Solutions of dopamine hydrochloride (1000 micrograms/mL) were prepared, and samples were subjected to one of three light sources (fluorescent, dark, phototherapy) and two flow rates (2 mL/hr and no flow) at ambient room temperature. Irradiation levels were maintained between 5.1 and 6.6 microwatts/sq cm throughout the experiment. Samples obtained at 0 to 36 hours were assayed using high-performance liquid chromatography. There were no significant differences in dopamine stability among the sample groups exposed to the various light and flow conditions over the 36-hour study period. Dopamine hydrochloride in 5% dextrose injection exposed to phototherapy is stable for 36 hours at 1000 micrograms/mL. It is not necessary to protect dopamine solutions from blue-light irradiance to ensure clinically acceptable stability.

Bilirubin dynamics in the Gunn rat. Dose response of intermittent and continuous phototherapy.

Jaundiced Gunn rats underwent continuous and intermittent phototherapy with white and blue lights. Irradiances ranged from 0.088 to 1.4 mW/cm2 in the blue (415-465 nm) wavelengths. Changes in serum bilirubin concentration were analyzed by a single exponential model. Dose-response curves for 10 days of phototherapy indicated similar logarithmic relationships between light dose and serum bilirubin decline for intermittent and continuous blue light and continuous white light phototherapy. The dose-response curve for intermittent white light showed a low slope and correlation coefficient.

ABO HEMOLYTIC DISEASE OF THE NEWBORN: EVALUATION OF MANAGEMENT AND IDENTIFICATION OF RACIAL AND ANTIGENIC FACTORS

Data from 16,320 deliveries from two time periods were examined to compare the incidence of positive direct Coombs' tests and the number of exchange transfusions performed, using different methods of screening and treatment in each time period. Early routine screening revealed an eightfold increase in the number of Coombs-positive infants, while the combined effect of instituting early screening and the change from white light to special blue light phototherapy greatly diminihsed the number of exchange transfusions. In addition, data concerning racial and blood antigen factors in ABO hemolytic disease of the newborn (HDN) are compared, showing an increase in incidence but no increase in severity for black infants and infants with blood type B. Also, use of cord blood parameters in management of ABO HDN is discussed.

ABO hemolytic disease of the newborn: evaluation of management and identification of racial and antigenic factors.

Data from 16,320 deliveries from two time periods were examined to compare the incidence of positive direct Coombs' tests and the number of exchange transfusions performed, using different methods of screening and treatment in each time period. Early routine screening revealed an eightfold increase in the number of Coombs-positive infants, while the combined effect of instituting early screening and the change from white light to special blue light phototherapy greatly diminihsed the number of exchange transfusions. In addition, data concerning racial and blood antigen factors in ABO hemolytic disease of the newborn (HDN) are compared, showing an increase in incidence but no increase in severity for black infants and infants with blood type B. Also, use of cord blood parameters in management of ABO HDN is discussed.

Effects of Phototherapy on Platelet Counts in Low-Birthweight Infants and on Platelet Production and Life Span in Rabbits

The effects of conventional phototherapy on platelets in vivo were studied in rabbits and in low-birthweight infants. Rabbits were divided into three groups and individually treated continuously for 96 hours, with blue light, daylight, or no phototherapy. Incorporation of selenomethionine Se75 was used to evaluate platelet production and life span. Platelet turnover was significantly increased in the blue-light phototherapy group, and was also increased in the daylight group but to a lesser degree. Daily platelet counts and hematocrits were performed in infants weighing less than 2,000 gm at birth randomized at 24 +/- 12 hours of life to receive daylight phototherapy continuously for 96 hours (31 infants) or no phototherapy (26 infants). In 12 treated infants (38.7%) platelet counts fell below 150,000/cu mm whereas this occurred in only 3 (11.5%) of the controls. These two lower platelet count subgroups differed significantly in mean gestational age and birthweight with the phototherapy group being the more mature. Pre-phototherapy, the mean platelet count of these 12 infants was lower than the mean of the entire control group, suggesting that these infants had borderline marrow reserve before phototherapy was given. These results suggest that phototherapy increases the rate of platelet turnover. When bone marrow compensation is inadequate, the platelet count may fall.