AIM: To determine whether the photopic negative response(Ph NR) elicited by transient white flash on white background is characterizing for glaucoma model in rabbits.METHODS: Glaucoma was induced in twelve rabbits by ...AIM: To determine whether the photopic negative response(Ph NR) elicited by transient white flash on white background is characterizing for glaucoma model in rabbits.METHODS: Glaucoma was induced in twelve rabbits by subconjunctival injection of 0.05 m L of betamethasone in right eyes(each 1 m L contain betamethasone dipropionate5 mg and betamethasone sodium phosphate 2 mg).The intraocular pressure(IOP), electroretinogram(ERG) and visual evoked potential(VEP) were measured successively prior and on the 3, 7d, two weeks and four weeks postglaucoma induction. After four weeks, the animals were sacrificed and the globes were histopathologically examined.RESULTS: The IOP increased significantly after one week(P =0.0001), then it gradually returned to the control level. In ERG examination, the means of a and b wave amplitude and latency were not affected significantly.Ph NR amplitude decreased significantly within one week(P =0.0001), but its latency was not affected significantly(P =0.132). The means of VEP latency and amplitude were significantly affected after two weeks and four weeks of glaucoma induction(P =0.0001 and 0.02,respectively). The histopathologic examination of the globes showed reduced number of cells in the retinal ganglion cell layer with multiple vacuoles in the retinal nerve fibre layer.There was significant positive correlation between ganglion cell layer cells and Ph NR amplitude( r =0.8, P =0.002).CONCLUSION: The rise in IOP resulted in irreversible changes or incomplete recovery of VEP and Ph NR amplitude. Both Ph NR and VEP represented good additional tools in early diagnosis of glaucoma.展开更多
I am Dr. David P Pifiero from the Department of Optics, Pharmacology and Anatomy of the University of Alicante and from the Department of Ophthalmology of Vithas Medimar （Oftalmar） and Vithas Virgen del Carmen （Qv...I am Dr. David P Pifiero from the Department of Optics, Pharmacology and Anatomy of the University of Alicante and from the Department of Ophthalmology of Vithas Medimar （Oftalmar） and Vithas Virgen del Carmen （Qvision） hospitals in Spain.展开更多
AIM:To determine the effects of change in light conditions on refractive error and visual functions including visual acuity,stereopsis and contrast sensitivity.METHODS:This cross-sectional study was conducted in the o...AIM:To determine the effects of change in light conditions on refractive error and visual functions including visual acuity,stereopsis and contrast sensitivity.METHODS:This cross-sectional study was conducted in the optometry clinic of the Shahid Beheshti School of Rehabilitation on 48 students in 2021-2022.All of them had eye health and normal visual function and could have refractive errors or not.Light intensity of 4 lx was considered equivalent to photopic light condition and light intensity of 1 lx was considered to be equivalent to mesopic light condition.The amount of refractive error was checked by auto refractometer and its changes in mesopic light condition were subjectively measured.Also,visual acuity,stereopsis and contrast sensitivity(in five spatial frequencies of 1.5,3,6,12,and 18 cycles per degree),were measured first in photopic light condition and then in mesopic light condition,by Snellen control vision chart,stereo butterfly test and the M&S technology monitor test respectively.RESULTS:In the 48 student subjects with an average age of 22.69±3.56y,mean of refractive error as sphere equivalent,visual acuity and stereopsis were-1.25±1.74 diopters,0 logMAR,44.37±13.03 seconds of arc,respectively in photopic light condition while in mesopic light was equal to-1.56±1.75 diopters,0.12±0.09 logMAR and 50.62±33.35 seconds of arc,respectively.The mean of contrast sensitivity measured at spatial frequencies of 1.5,3,6,12,and 18 cycles per degree in photopic condition was equal to 2.38±0.04,2.37±0.07,2.04±0.21,1.27±0.32,0.82±0.27 logarithm of contrast sensitivity,respectively and in mesopic lighting condition was equal to 2.34±0.12,2.30±0.16,1.84±0.28,1.02±0.28,0.63±0.24 logarithm of contrast sensitivity,respectively.Statistical analysis showed a significant difference between the two lighting conditions in all evaluated variables[refractive error(P<0.001),visual acuity(P<0.001),stereopsis(P=0.008)and contrast sensitivity(P<0.001)].CONCLUSION:The refractive error of the student subjects in mesopic light condition change towards myopia,and its amount is clinically significant.Also,the examination and comparison of the factors of visual acuity,stereopsis and contrast sensitivity in these two lighting conditions show that the decrease in brightness level to the mesopic level causes a decrease in the aforementioned visual functions.展开更多
With the increasing attention on circadian effects driven by light,lighting industry has inspired a revolution of photobiological lighting design.Due to diverse evaluation criteria for visual and non⁃visual systems,mo...With the increasing attention on circadian effects driven by light,lighting industry has inspired a revolution of photobiological lighting design.Due to diverse evaluation criteria for visual and non⁃visual systems,models that combine these evaluation parameters are indeed urgent.Thus,an integrated model for mesopic lighting evaluation of circadian effects was proposed.The circadian efficiency function adopted in this study was synthesized by CIE 1931 XYZ 2 deg color matching functions and standard scotopic sensitivity function.Then,the integrated model composed of International Commission on Illumination 1931 xy chromaticity coordinates,scotopic/photopic ratio,and illuminance could be obtained with synthesized circadian efficiency function.The model showed that for light sources with fixed chromaticity coordinates and fixed illuminance,enhancing the circadian effects is equivalent to increasing the scotopic/photopic ratio,which suggests a useful method for practitioners to explore the photobiologically reasonable spectrum for mesopic lighting.Light⁃emitting diodes spectra optimized by four⁃component color⁃mixing method were employed to figure out the property of the integrated model.展开更多
The visible portion of spectrum covers the wavelength range from approximately 380nm to 780nm and the eye discriminates between different wavelengths in this range by the sensation of colour.
A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found t...A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green,red and blue emitters.While the luminance enhancements of blue and red phosphorescent microcavity devices are small,a current efficiency as high as 224 cd A21 is obtained in the green phosphorescent microcavity OLEDs.展开更多
A series of opaque and semitransparent polymer solar cells(PSCs)were fabricated with PM6:Y6 as active layers,and 100 nm Al or 1 nm Au/(20,15,10 nm)Ag layer as electrode,respectively.The power conversion efficiency(PCE...A series of opaque and semitransparent polymer solar cells(PSCs)were fabricated with PM6:Y6 as active layers,and 100 nm Al or 1 nm Au/(20,15,10 nm)Ag layer as electrode,respectively.The power conversion efficiency(PCE)of opaque PSCs arrives to 15.83%based on the optimized active layer with a thickness of 100 nm,resulting from the well-balanced photon harvesting and charge collection.Meanwhile,the 100 nm PM6:Y6 blend film exhibits a 50.5%average visible transmittance(AVT),which has great potential in preparing efficient semitransparent PSCs.The semitransparent electrodes were fabricated with 1 nm Au and different thick Ag layers,exhibiting a relatively high transmittance in visible light range and relatively low transmittance in near infrared range.The PCE and AVT of the semitransparent PSCs can be adjusted from 14.20%to 12.37%and from 8.9%to 18.6%along with Ag layer thickness decreasing from 20 to 10 nm,respectively,which are impressive values among the reported semitransparent PSCs.展开更多
Background:Cataract,a leading cause of vision impairment,is due to the lens becoming excessively optically dense.Change in the lens optical density(LOD)could be a useful indicator of incipient nuclear cataract and wou...Background:Cataract,a leading cause of vision impairment,is due to the lens becoming excessively optically dense.Change in the lens optical density(LOD)could be a useful indicator of incipient nuclear cataract and would necessitate the development of accurate measurement techniques.Mapcat sf^(TM) is a heterochromatic flicker photometer for measuring macular pigment optical density(MPOD)under photopic conditions.In the process,it also measures LOD that is needed in the calculation of MPOD.LOD is then converted by the instrument to“lens equivalent age”(LEA).However,varying cone photoreceptor ratios among individuals could affect the LEA measurement.Scotopic vision is mediated by rod photoreceptors;therefore,LEA measurement under scotopic conditions potentially provides a reliable standard for assessing other methods.The study was conducted to test the level of agreement between the LEA data obtained under photopic and scotopic conditions for a sample population.We also comment on factors that might contribute to any disagreement.Methods:LEAs were obtained by Mapcat sf for 25 subjects and compared with those obtained under absolute scotopic threshold conditions.Results:The mean scotopic LEA for the subjects was 2.7 years higher than the mean photopic LEA,but this difference was not statistically significant.Measurements by the two methods were reasonably correlated(r 2=0.59,p<0.0001).Significant individual differences in LEA by the two methods were found for six of the 25 subjects.Although our calculations included a standard long-to medium-wavelength-sensitive cone ratio,we found that different ratios could be found that rendered the differences in LEA insignificant for two of these six subjects.Variability in pupil diameter during scotopic measurements was considered another potential source of discrepancy between LEAs by the two methods.Conclusion:The absolute threshold technique,with long adaptation times,is probably impractical for routine lens density measurement,whereas Mapcat sf provided a rapid,straightforward test that may find its application in optometric/ophthalmic practice.展开更多
文摘AIM: To determine whether the photopic negative response(Ph NR) elicited by transient white flash on white background is characterizing for glaucoma model in rabbits.METHODS: Glaucoma was induced in twelve rabbits by subconjunctival injection of 0.05 m L of betamethasone in right eyes(each 1 m L contain betamethasone dipropionate5 mg and betamethasone sodium phosphate 2 mg).The intraocular pressure(IOP), electroretinogram(ERG) and visual evoked potential(VEP) were measured successively prior and on the 3, 7d, two weeks and four weeks postglaucoma induction. After four weeks, the animals were sacrificed and the globes were histopathologically examined.RESULTS: The IOP increased significantly after one week(P =0.0001), then it gradually returned to the control level. In ERG examination, the means of a and b wave amplitude and latency were not affected significantly.Ph NR amplitude decreased significantly within one week(P =0.0001), but its latency was not affected significantly(P =0.132). The means of VEP latency and amplitude were significantly affected after two weeks and four weeks of glaucoma induction(P =0.0001 and 0.02,respectively). The histopathologic examination of the globes showed reduced number of cells in the retinal ganglion cell layer with multiple vacuoles in the retinal nerve fibre layer.There was significant positive correlation between ganglion cell layer cells and Ph NR amplitude( r =0.8, P =0.002).CONCLUSION: The rise in IOP resulted in irreversible changes or incomplete recovery of VEP and Ph NR amplitude. Both Ph NR and VEP represented good additional tools in early diagnosis of glaucoma.
文摘I am Dr. David P Pifiero from the Department of Optics, Pharmacology and Anatomy of the University of Alicante and from the Department of Ophthalmology of Vithas Medimar （Oftalmar） and Vithas Virgen del Carmen （Qvision） hospitals in Spain.
文摘AIM:To determine the effects of change in light conditions on refractive error and visual functions including visual acuity,stereopsis and contrast sensitivity.METHODS:This cross-sectional study was conducted in the optometry clinic of the Shahid Beheshti School of Rehabilitation on 48 students in 2021-2022.All of them had eye health and normal visual function and could have refractive errors or not.Light intensity of 4 lx was considered equivalent to photopic light condition and light intensity of 1 lx was considered to be equivalent to mesopic light condition.The amount of refractive error was checked by auto refractometer and its changes in mesopic light condition were subjectively measured.Also,visual acuity,stereopsis and contrast sensitivity(in five spatial frequencies of 1.5,3,6,12,and 18 cycles per degree),were measured first in photopic light condition and then in mesopic light condition,by Snellen control vision chart,stereo butterfly test and the M&S technology monitor test respectively.RESULTS:In the 48 student subjects with an average age of 22.69±3.56y,mean of refractive error as sphere equivalent,visual acuity and stereopsis were-1.25±1.74 diopters,0 logMAR,44.37±13.03 seconds of arc,respectively in photopic light condition while in mesopic light was equal to-1.56±1.75 diopters,0.12±0.09 logMAR and 50.62±33.35 seconds of arc,respectively.The mean of contrast sensitivity measured at spatial frequencies of 1.5,3,6,12,and 18 cycles per degree in photopic condition was equal to 2.38±0.04,2.37±0.07,2.04±0.21,1.27±0.32,0.82±0.27 logarithm of contrast sensitivity,respectively and in mesopic lighting condition was equal to 2.34±0.12,2.30±0.16,1.84±0.28,1.02±0.28,0.63±0.24 logarithm of contrast sensitivity,respectively.Statistical analysis showed a significant difference between the two lighting conditions in all evaluated variables[refractive error(P<0.001),visual acuity(P<0.001),stereopsis(P=0.008)and contrast sensitivity(P<0.001)].CONCLUSION:The refractive error of the student subjects in mesopic light condition change towards myopia,and its amount is clinically significant.Also,the examination and comparison of the factors of visual acuity,stereopsis and contrast sensitivity in these two lighting conditions show that the decrease in brightness level to the mesopic level causes a decrease in the aforementioned visual functions.
基金Sponsored by the Opening Funds of State Key Laboratory of Building Safety and Built Environment and National Engineering Research Center of Building Technology(Grant No.BSBE2018-01)the Fundamental Research Funds for the Central Universities(Grant No.2018ZD34)the Autonomous Research Project of State Key Laboratory of Subtropical Building Science(Grant No.2017KB11).
文摘With the increasing attention on circadian effects driven by light,lighting industry has inspired a revolution of photobiological lighting design.Due to diverse evaluation criteria for visual and non⁃visual systems,models that combine these evaluation parameters are indeed urgent.Thus,an integrated model for mesopic lighting evaluation of circadian effects was proposed.The circadian efficiency function adopted in this study was synthesized by CIE 1931 XYZ 2 deg color matching functions and standard scotopic sensitivity function.Then,the integrated model composed of International Commission on Illumination 1931 xy chromaticity coordinates,scotopic/photopic ratio,and illuminance could be obtained with synthesized circadian efficiency function.The model showed that for light sources with fixed chromaticity coordinates and fixed illuminance,enhancing the circadian effects is equivalent to increasing the scotopic/photopic ratio,which suggests a useful method for practitioners to explore the photobiologically reasonable spectrum for mesopic lighting.Light⁃emitting diodes spectra optimized by four⁃component color⁃mixing method were employed to figure out the property of the integrated model.
文摘The visible portion of spectrum covers the wavelength range from approximately 380nm to 780nm and the eye discriminates between different wavelengths in this range by the sensation of colour.
文摘A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green,red and blue emitters.While the luminance enhancements of blue and red phosphorescent microcavity devices are small,a current efficiency as high as 224 cd A21 is obtained in the green phosphorescent microcavity OLEDs.
基金financially supported by the National Natural Science Foundation of China(61675017,61975006)Beijing Natural Science Foundation(4192049).
文摘A series of opaque and semitransparent polymer solar cells(PSCs)were fabricated with PM6:Y6 as active layers,and 100 nm Al or 1 nm Au/(20,15,10 nm)Ag layer as electrode,respectively.The power conversion efficiency(PCE)of opaque PSCs arrives to 15.83%based on the optimized active layer with a thickness of 100 nm,resulting from the well-balanced photon harvesting and charge collection.Meanwhile,the 100 nm PM6:Y6 blend film exhibits a 50.5%average visible transmittance(AVT),which has great potential in preparing efficient semitransparent PSCs.The semitransparent electrodes were fabricated with 1 nm Au and different thick Ag layers,exhibiting a relatively high transmittance in visible light range and relatively low transmittance in near infrared range.The PCE and AVT of the semitransparent PSCs can be adjusted from 14.20%to 12.37%and from 8.9%to 18.6%along with Ag layer thickness decreasing from 20 to 10 nm,respectively,which are impressive values among the reported semitransparent PSCs.
文摘Background:Cataract,a leading cause of vision impairment,is due to the lens becoming excessively optically dense.Change in the lens optical density(LOD)could be a useful indicator of incipient nuclear cataract and would necessitate the development of accurate measurement techniques.Mapcat sf^(TM) is a heterochromatic flicker photometer for measuring macular pigment optical density(MPOD)under photopic conditions.In the process,it also measures LOD that is needed in the calculation of MPOD.LOD is then converted by the instrument to“lens equivalent age”(LEA).However,varying cone photoreceptor ratios among individuals could affect the LEA measurement.Scotopic vision is mediated by rod photoreceptors;therefore,LEA measurement under scotopic conditions potentially provides a reliable standard for assessing other methods.The study was conducted to test the level of agreement between the LEA data obtained under photopic and scotopic conditions for a sample population.We also comment on factors that might contribute to any disagreement.Methods:LEAs were obtained by Mapcat sf for 25 subjects and compared with those obtained under absolute scotopic threshold conditions.Results:The mean scotopic LEA for the subjects was 2.7 years higher than the mean photopic LEA,but this difference was not statistically significant.Measurements by the two methods were reasonably correlated(r 2=0.59,p<0.0001).Significant individual differences in LEA by the two methods were found for six of the 25 subjects.Although our calculations included a standard long-to medium-wavelength-sensitive cone ratio,we found that different ratios could be found that rendered the differences in LEA insignificant for two of these six subjects.Variability in pupil diameter during scotopic measurements was considered another potential source of discrepancy between LEAs by the two methods.Conclusion:The absolute threshold technique,with long adaptation times,is probably impractical for routine lens density measurement,whereas Mapcat sf provided a rapid,straightforward test that may find its application in optometric/ophthalmic practice.
