AIM:To evaluate and compare alterations in the effective lens position(ELP)and refractive outcomes among three distinct intraocular lens(IOL)types.METHODS:Patients with cataracts were enrolled and allocated to 3 group...AIM:To evaluate and compare alterations in the effective lens position(ELP)and refractive outcomes among three distinct intraocular lens(IOL)types.METHODS:Patients with cataracts were enrolled and allocated to 3 groups:Group A(implanted with the SN6CWS),Group B(implanted with the MI60),and Group C(implanted with the Aspira-aA).ELP measurements were obtained with swept-source optical coherence tomography(SS-OCT)at 1d,1wk,1mo,and 3mo postoperatively.Subjective refraction assessments were conducted at 1wk,1mo,and 3mo following surgery.RESULTS:The study included 189 eyes of 150 cataract patients(66 males).There were 77 eyes in Group A,55 eyes in Group B,and 57 eyes in Group C.The root mean square of the ELP(ELPRMS)within the initial 3mo was significantly lower for Group A than for Groups B and C.Refractive changes within Group A were not significant across the time points of 1wk,1mo,and 3mo.Conversely,both Group B and Group C demonstrated statistically significant shifts toward hyperopia from 1wk to 3mo postsurgery.CONCLUSION:Among the three IOLs examined,the SN6CWS IOL showes the greatest stability during the first 3mo postoperatively.Between 1wk and 3mo after surgery,notable hyperopic shifts are evident in eyes implanted with the MI60 and Aspira-aA IOLs,whereas refractive outcomes remain relatively constant in eyes implanted with SN6CWS IOLs.展开更多
AIM:To compare objective dry retinoscopy and subjective refraction measurements in patients with mild keratoconus(KCN)and quantify any differences.METHODS:This cross-sectional study was done on 68 eyes of 68 patients ...AIM:To compare objective dry retinoscopy and subjective refraction measurements in patients with mild keratoconus(KCN)and quantify any differences.METHODS:This cross-sectional study was done on 68 eyes of 68 patients diagnosed with mild KCN.Objective dry retinoscopy using autorefractometer and subjective refraction measurements were performed.Sphere,cylinder,J0,J45,and spherical equivalent values were compared between the two techniques.RESULTS:The mean age of 68 patients with mild KCN was 21.32±5.03y(12–35y).There were 37(54.4%)males.Objective refraction yielded significantly more myopic sphere(-1.44 D vs-0.57 D),higher cylinder magnitude(-2.24 D vs-1.48 D),and more myopic spherical equivalent(-2.56 D vs-1.31 D)compared to subjective refraction(all P<0.05).The mean differences were-0.87 D for sphere,-0.76 D for cylinder,and-1.25 D for spherical equivalent.No significant differences were found for J0 and J45 values,indicating agreement in astigmatism axis(P>0.05).CONCLUSION:In patients with mild KCN,objective dry retinoscopy overestimates the degree of myopia and astigmatism compared to subjective refraction.The irregular cornea in KCN likely impacts objective measurements.Subjective refraction allows compensation for irregularity,providing a more accurate correction.When determining refractive targets,the tendency of objective methods to overcorrect should be considered.展开更多
AIM:To compare the subjective refraction data with autorefraction findings in high astigmatisms.METHODS:In a cross-sectional study,sampling was done from in different geographic regions in Iran using a multistage rand...AIM:To compare the subjective refraction data with autorefraction findings in high astigmatisms.METHODS:In a cross-sectional study,sampling was done from in different geographic regions in Iran using a multistage random cluster sampling method.All study participants underwent cycloplegic auto-refraction and subjective refraction using the red-green test.RESULTS:In this study,277 eyes of 158 students aged 8 to 15y were analyzed.According to the results,the mean difference between subjective refraction and autorefraction in measuring sphere,cylinder,spherical equivalent,J0,and J45 was-0.18±0.76,-0.36±0.40,-0.36±0.79,0.15±0.20,and 0.05±0.21 respectively.The correlation of these two refraction methods in measuring the aforementioned indices was 0.963,0.898,0.960,0.931,and 0.948 respectively.The 95%limits of agreement of the two methods in measuring the above indices were-1.66 to 1.31,-1.14 to 0.42,-1.91 to 1.19,-0.24 to 0.54,and-0.36 to 0.47 respectively.The agreement between the two methods decreased with increasing cylinder power,and the best agreement was found in myopic individuals.CONCLUSION:The measurements obtained by autorefractometer have a significantly higher cylinder average compared to subjective refraction.However,in the cylinder range of 4–5 diopters,the values of J0 and J45 do not have a high correlation.展开更多
The emergent metagrating,with its unique and flexible beam shaping capabilities,offers new paths to efficient modulation of acoustic waves.In this work,an acoustic metagrating is demonstrated for high-efficiency and w...The emergent metagrating,with its unique and flexible beam shaping capabilities,offers new paths to efficient modulation of acoustic waves.In this work,an acoustic metagrating is demonstrated for high-efficiency and wide-angle anomalous refraction.It is shown that the normal reflection and transmission can be totally suppressed by properly modulating the amplitude and phase characteristics of the metagrating supercells for high-efficiency anomalous refraction.The anomalous refraction behavior is achieved in the wide range of incident angles from 28°to 78°,and the efficiency of-1st order diffraction is higher than 90%by finely designing the metagrating structure.The anomalous refraction behaviors are verified experimentally at incidence angle of 28°,45°,and 78°,respectively.The demonstrated metagrating is anticipated to possess efficient wide-angle composite wavefront engineering applications in such fields as communications.展开更多
Ocular biological characteristics and refractive errors in children with unilateral congenital ptosis Yu-Ying Sun,Bing-Ying Lin,Zhen Mao,Xuan-Wei Liang,Cui-Yu Zhang,Dan-Ping Huang,Yao Ni,Zuo-Hong Li Int J Ophthalmol 2...Ocular biological characteristics and refractive errors in children with unilateral congenital ptosis Yu-Ying Sun,Bing-Ying Lin,Zhen Mao,Xuan-Wei Liang,Cui-Yu Zhang,Dan-Ping Huang,Yao Ni,Zuo-Hong Li Int J Ophthalmol 2025;18(4):691-698.DOI:10.18240/ijo.2025.04.16 The author requests to change the authorship and affiliations as follows.展开更多
AIM: To report the visual outcomes and refractive status in premature infants with and without retinopathy of prematurity(ROP) who were or not treated. METHODS: The clinical records of all premature infants with or wi...AIM: To report the visual outcomes and refractive status in premature infants with and without retinopathy of prematurity(ROP) who were or not treated. METHODS: The clinical records of all premature infants with or without ROP and with or without treatment between 2007 and 2017 were retrospectively reviewed. Basic demographic data, serial changes in ROP incidence, treatment and outcomes, and the refractive states were analyzed. Correlations among myopia and astigmatism progression, birth weight, gestational age, and treatment methods were also analyzed.RESULTS: A total of 562 screened premature infants(all Chinese, 1124 eyes), were recruited with a 378:184 maleto-female ratio. Birth weight did not directly influence ROP incidence. The overall ROP incidence was 16.55%(93/562 cases). The incidences in boys and girls were 16.14%(33/378 cases) and 17.39%(32/184 cases), respectively, and this difference was not significant. However, all infants with serious ROP(stage IV and V) were male. Myopia combined with astigmatism was common in premature infants with and without ROP(30.99%, 172/555 cases), and myopic refraction(including myopia and myopia combined with astigmatism) was more common in premature infants with ROP(48.84%, 42/86 cases). In the >8.00 diopter group, there were significantly more ROP infants than without ROP. Myopic refraction(including myopia and myopia combined with astigmatism) was most common in infants with ROP after treatment(63.63%, 7/11 cases). CONCLUSION: The refractive state is different between premature infants and mature infants. Those treated for ROP had a higher chance of developing myopia, astigmatism, and higher diopter.展开更多
AIM: To compare the results of noncycloplegic photorefraction, cycloplegic photorefraction and cycloplegic refraction in preschool and non-verbal children.METHODS: One hundred and ninety-six eyes of 98children(50 fema...AIM: To compare the results of noncycloplegic photorefraction, cycloplegic photorefraction and cycloplegic refraction in preschool and non-verbal children.METHODS: One hundred and ninety-six eyes of 98children(50 females, 48 males) were included in the study. Firstly, non-cycloplegic photorefraction was achieved with Plusoptix A09; secondly, cycloplegic photorefraction was carried out with Plusoptix A09 after10 min cyclopentolate. Finally, 30 min after instillation of twice cyclopentolate, cycloplegic refraction was obtained with autorefraction and/or standard retinoscopy. Spheric equivalent, spheric power, cylindric power and cylindrical axis measurements were statistically compared.RESULTS: The mean age was 28.8±18.5mo(range12-72mo). The differences in spherical equivalent, spheric power and cylindrical power measured by the three methods were found statistically significant(P 【0.05).The spherical equivalent and spheric power measured by cycloplegic photorefraction were statistically higher than the measurements of the other methods(P 【0.05). The cylindrical power measured by cycloplegic refraction was statistically lower than the measurements of the photorefraction methods(P 【0.05). There was no significant difference in cylindrical axis measurements between three methods(P 】0.05).CONCLUSION: For the determination of refractive errors in children, the Plusoptix A09 measurements give incorrect results after instillation of cyclopentolate.Additionally, the cylindrical power measured by Plusoptix A09 with or without cycloplegia is higher. However, the non-cycloplegic Plusoptix A09 measures spheric equivalent and spheric power similar to cycloplegic refraction measurements in preschool and non-verbal children.展开更多
Underwater navigation system is an indispensable part for autonomous underwater vehicles.Due to the indiscernibility of satellite signal,however,the underwater navigation problem is quite challenging,and a satellite-f...Underwater navigation system is an indispensable part for autonomous underwater vehicles.Due to the indiscernibility of satellite signal,however,the underwater navigation problem is quite challenging,and a satellite-free navigation scheme should be looked for.Polarization navigation,inspired by insects’capability of autonomous homing and foraging,is an alternative solution to satellite navigation with great application potential.Underwater polarization provides an indirect sun compass to animals for orientation determination.However,it is difficult to apply terrestrial solar-tracking methodologies in underwater situations due to the refraction of polarized skylight at the air–water interface.To resolve this issue,an underwater solar-tracking algorithm is developed based on the underwater refraction-polarization pattern inside the Snell’s window.By employing Snell’s law and Fresnel refraction formula to decouple the refractive ray bending and polarization deflection,the celestial polarization pattern is obtained based on underwater measurement.To further improve the accuracy,the degree of polarization is employed as a weight factor for E-vector.A long-lasting underwater experiment was conducted to validate the effectiveness of the proposed approach,and the results showed the root-mean-square errors of solar zenith and azimuth employing this algorithm were 0.3°and 1.3°,respectively.Our experimental results show that the refraction-polarization pattern inside the Snell’s window exhibits immense potential to improve the solar-tracking accuracy for underwater navigation.展开更多
BACKGROUND Myopia,as one of the common ocular diseases,often occurs in adolescence.In addition to the harm from itself,it may also lead to serious complications.Thus,prevention and control of myopia are attracting mor...BACKGROUND Myopia,as one of the common ocular diseases,often occurs in adolescence.In addition to the harm from itself,it may also lead to serious complications.Thus,prevention and control of myopia are attracting more and more attention.Previous research revealed that single-focal glasses and orthokeratology lenses(OK lenses)played an important part in slowing down myopia and preventing high myopia.AIM To compare the clinical effects of OK lenses and frame glasses against the increase of diopter in adolescent myopia and further explore the mechanism of the OK lens.METHODS Changes in diopter and axial length were collected among 70 adolescent myopia patients(124 eyes)wearing OK lenses for 1 year(group A)and 59 adolescent myopia patients(113 eyes)wearing frame glasses(group B).Refractive states of their retina were inspected through multispectral refraction topography.The obtained hyperopic defocus was analyzed for the mechanism of OK lenses on slowing down the increase of myopic diopter by delaying the increase of ocular axis length and reducing the near hyperopia defocus.RESULTS Teenagers in groups A and B were divided into low myopia(0 D--3.00 D)and moderate myopia(-3.25 D--6.00 D),without statistical differences among gender and age.After 1-year treatment,the increase of diopter and axis length and changes of retinal hyperopic defocus amount of group A were significantly less than those of group B.According to the multiple linear analysis,the retinal defocus in the upper,lower,nasal,and temporal directions had almost the same effect on the total defocus.The amount of peripheral retinal defocus(15°-53°)in group A was significantly lower than that in group B.CONCLUSION Multispectral refraction topography is progressive and instructive in clinical prevention and control of myopia.展开更多
AIM:To characterize peripheral refraction and its relationship with myopia development in a selected group of male teenage Chinese students.METHODS:This 2-year prospective cohort study randomly enrolled 85 non-myopic ...AIM:To characterize peripheral refraction and its relationship with myopia development in a selected group of male teenage Chinese students.METHODS:This 2-year prospective cohort study randomly enrolled 85 non-myopic boys(age,14-16 y)from the Experimental Class of Air Force in China.Cycloplegic peripheral refraction was examined at 0°,±10°,and±20°along the horizontal visual field in the right eye at the baseline and 2-year follow-up.RESULTS:The incidence of myopia at the 2-year followup was 15.29%(13/85).The baseline central refraction(CR)and peripheral refraction at±10°were significantly lower in students who developed myopia than in those who did not(P<0.05).Relative peripheral refraction(RPR)did not differ between students with and without myopia(P>0.05).At the 2-year follow-up,the RPR at±10°and 20°nasal was significantly more hyperopic in the myopic group than in the non-myopic group.Multiple linear regression analysis indicated that the change in CR was significantly correlated with the changes in RPR at 20°nasal,10°nasal,and 20°temporal.Multivariate Logistic regression analysis indicated that the baseline CR[odds ratio(OR):0.092,95%confidence interval(CI):0.012-0.688,P=0.020]and the baseline RPR at 10°nasal(OR:0.182,95%CI:0.042-0.799,P=0.024)were significantly correlated with incident myopia(Omnibus test,χ=10.20,P=0.006).CONCLUSION:CR change is significantly correlated with changes in RPR,and students who develop myopia have more relative peripheral hyperopia.More baseline CR and relative peripheral hyperopia at 10°nasal are protective of myopia onset.展开更多
Autonomous orbit determination via integration of epoch-differenced gravity gradients and starlight refraction is proposed in this paper for low-Earth-orbiting satellites operating in GPSdenied environments. Starlight...Autonomous orbit determination via integration of epoch-differenced gravity gradients and starlight refraction is proposed in this paper for low-Earth-orbiting satellites operating in GPSdenied environments. Starlight refraction compensates for the significant along-track position error that occurs from only using gravity gradients and benefits from integration in terms of improved accuracy in radial and cross-track position estimates. The between-epoch differencing of gravity gradients is employed to eliminate slowly varying measurement biases and noise near the orbit revolution frequency. The refraction angle measurements are directly used and its Jacobian matrix derived from an implicit observation equation. An information fusion filter based on a sequential extended Kalman filter is developed for the orbit determination. Truth-model simulations are used to test the performance of the algorithm, and the effects of differencing intervals and orbital heights are analyzed. A semi-simulation study using actual gravity gradient data from the Gravity field and steady-state Ocean Circulation Explorer（GOCE） combined with simulated starlight refraction measurements is further conducted, and a three-dimensional position accuracy of better than 100 m is achieved.展开更多
AIM:To investigate the differences in retinal refraction difference values(RDVs)of adult patients with myopic anisometropia compared with those without myopic anisometropia,and to investigate the relationship between ...AIM:To investigate the differences in retinal refraction difference values(RDVs)of adult patients with myopic anisometropia compared with those without myopic anisometropia,and to investigate the relationship between ocular biometric measurements and relative peripheral refraction.METHODS:This clinical observation study included 130 patients with myopia(-0.25 to-10.00 D)between October 2022 and January 2023 aged between 18 and 40y.The patients were divided into anisometropia(n=63;difference in binocular anisometropia≥1.00 D)and non-anisometropia(n=67;difference in binocular anisometropia<1.00 D)groups accordingly.Ocular biometric measurements were performed by optical biometrics and corneal topography to assess the steep keratometry(Ks),flap keratometry(Kf),axial length(AL),corneal astigmatism(CYL;Ks-Kf),surface regularity index(SRI),surface asymmetry index(SAI),and central corneal thickness(CCT).The RDV was measured at five retinal areas from the fovea to 53 degrees(RDV-0-10,RDV-10-20,RDV-20-30,RDV-30-40,and RDV-40-53),the total RDV(TRDV)of 53 degrees,and four regions,including RDV-superior,RDV-inferior,RDV-temporal,and RDV-nasal.An analysis of Spearman correlation was carried out to examine the correlation between RDV and the spherical equivalent(SE)and ocular biological parameters.RESULTS:Within RDV-20-53,both groups showed relative hyperopic defocus,and the increase in RDV corresponds to the increase in eccentricity.In the myopic anisometropia group,the TRDV,RDV-20-53,RDV-superior,and more myopic eyes had significantly higher RDVtemporal values than less myopic eyes.(P<0.05).In the non-anisometropia group,there was no significant difference in the RDV between the more and less myopic eyes at different eccentricities(P>0.05).There was a negative correlation between SE and TRDV(r=-0.205,P=0.001),RDV-20-53(r=-0.281,-0.183,-0.176,P<0.05),RDV-superior(r=-0.251,P<0.001),and RDV-temporal(r=-0.230,P<0.001),a negative correlation between CYL and RDV-10-30(r=-0.147,-0.180,P<0.05),and a negative correlation between SRI and RDV-0-20(r=-0.190,-0.170,P<0.05).AL had a positive correlation with RDV-20-30(r=0.164,P=0.008)and RDV-temporal(r=0.160,P=0.010).CONCLUSION:More myopic eyes in patients with myopic anisometropia show more peripheral hyperopic defocus.Diopter and corneal morphology may affect peripheral retinal defocus.展开更多
The propagation of elastic waves is studied in a porous solid saturated with two immiscible viscous fluids. The propagation of three longitudinal waves is represented through three scalar potential functions. The lone...The propagation of elastic waves is studied in a porous solid saturated with two immiscible viscous fluids. The propagation of three longitudinal waves is represented through three scalar potential functions. The lone transverse wave is presented by a vector potential function. The displacements of particles in different phases of the aggregate are defined in terms of these potential functions. It is shown that there exist three longitudinal waves and one transverse wave. The phenomena of reflection and refraction due to longitudinal and transverse waves at a plane interface between an elastic solid half-space and a porous solid half-space saturated with two immiscible viscous fluids are investigated. For the presence of viscosity in pore-fluids, the waves refracted to the porous medium attenuate in the direction normal to the interface. The ratios of the amplitudes of the reflected and refracted waves to that of the incident wave are calculated as a non- singular system of linear algebraic equations. These amplitude ratios are used to further calculate the shares of different scattered waves in the energy of the incident wave. The modulus of the amplitude and the energy ratios with the angle of incidence are computed for a particular numerical model. The conservation of the energy across the interface is verified. The effects of variations in non-wet saturation of pores and frequencies on the energy partition are depicted graphically and discussed,展开更多
A numerical model based on the mild-slope equation of water wave propagation over complicated bathymetry,taking into account the combined effects of refraction,diffraction and dissipation due to wavebreaking is presen...A numerical model based on the mild-slope equation of water wave propagation over complicated bathymetry,taking into account the combined effects of refraction,diffraction and dissipation due to wavebreaking is presented.Wave breaking is simulated by modifying the wave height probability density func-tion and the wave energy dissipation mechanism is parameterized according to that of the hydraulic jumpformulation.Solutions of the wave height,phase function,and the wave direction at every grid point areobtained by finite difference approximation of the governing equations,using Gauss-Seidel Iterative Method(GSIM)row by row.Its computational convenience allows it to be applied to large coast regions tostudy the wave transformation problem.Several case studies have been made and the results compare verywell with the experiment data and other model solutions.The capability and utility of the model forreal coast areas are illustrated by application to a shallow bay of northeast Australia.展开更多
Sinkholes and cavities can represent serious hazards to human safety and urban infrastructures,cause roadbed subsidence,and so on.It is therefore essential to evaluate various sinkholes in different depths and sizes t...Sinkholes and cavities can represent serious hazards to human safety and urban infrastructures,cause roadbed subsidence,and so on.It is therefore essential to evaluate various sinkholes in different depths and sizes to assess the risk of collapse.This paper evaluates the effect of different cavities on Rayleigh-wave propagation and body(P)wave refraction.Rayleigh(R)wave propagation is analyzed according to the classical multi-channel analysis of surface waves(MASW)method also considering the R-wave backscattering.Synthetic seismic traces are computed by means of finite element modeling(FEM)for cavity and intrusion at different depths and sizes.Furthermore,field acquisition data is used to verify the detection effect of a cavity on R-and P-waves.The results show that the presence of backscattered R-waves and the changes in the R-wave velocity spectrum can help in cavity identification.Additional possible evidence is represented by significant changes in the refraction travel times over the cavity location.It can be concluded that the field data are in good agreement with the synthetic,and it could be effective to consider the results of both R-and P-wave analysis in order to efficiently identify the cavities.展开更多
基金Supported by the Zhejiang Medical Health Science and Technology Project(No.2021KY217)the Basic Public Welfare Research Project of Wenzhou Municipal Science and Technology Bureau(No.2024Y1221).
文摘AIM:To evaluate and compare alterations in the effective lens position(ELP)and refractive outcomes among three distinct intraocular lens(IOL)types.METHODS:Patients with cataracts were enrolled and allocated to 3 groups:Group A(implanted with the SN6CWS),Group B(implanted with the MI60),and Group C(implanted with the Aspira-aA).ELP measurements were obtained with swept-source optical coherence tomography(SS-OCT)at 1d,1wk,1mo,and 3mo postoperatively.Subjective refraction assessments were conducted at 1wk,1mo,and 3mo following surgery.RESULTS:The study included 189 eyes of 150 cataract patients(66 males).There were 77 eyes in Group A,55 eyes in Group B,and 57 eyes in Group C.The root mean square of the ELP(ELPRMS)within the initial 3mo was significantly lower for Group A than for Groups B and C.Refractive changes within Group A were not significant across the time points of 1wk,1mo,and 3mo.Conversely,both Group B and Group C demonstrated statistically significant shifts toward hyperopia from 1wk to 3mo postsurgery.CONCLUSION:Among the three IOLs examined,the SN6CWS IOL showes the greatest stability during the first 3mo postoperatively.Between 1wk and 3mo after surgery,notable hyperopic shifts are evident in eyes implanted with the MI60 and Aspira-aA IOLs,whereas refractive outcomes remain relatively constant in eyes implanted with SN6CWS IOLs.
文摘AIM:To compare objective dry retinoscopy and subjective refraction measurements in patients with mild keratoconus(KCN)and quantify any differences.METHODS:This cross-sectional study was done on 68 eyes of 68 patients diagnosed with mild KCN.Objective dry retinoscopy using autorefractometer and subjective refraction measurements were performed.Sphere,cylinder,J0,J45,and spherical equivalent values were compared between the two techniques.RESULTS:The mean age of 68 patients with mild KCN was 21.32±5.03y(12–35y).There were 37(54.4%)males.Objective refraction yielded significantly more myopic sphere(-1.44 D vs-0.57 D),higher cylinder magnitude(-2.24 D vs-1.48 D),and more myopic spherical equivalent(-2.56 D vs-1.31 D)compared to subjective refraction(all P<0.05).The mean differences were-0.87 D for sphere,-0.76 D for cylinder,and-1.25 D for spherical equivalent.No significant differences were found for J0 and J45 values,indicating agreement in astigmatism axis(P>0.05).CONCLUSION:In patients with mild KCN,objective dry retinoscopy overestimates the degree of myopia and astigmatism compared to subjective refraction.The irregular cornea in KCN likely impacts objective measurements.Subjective refraction allows compensation for irregularity,providing a more accurate correction.When determining refractive targets,the tendency of objective methods to overcorrect should be considered.
基金Supported by Shahid Beheshti University of Medical Sciences.
文摘AIM:To compare the subjective refraction data with autorefraction findings in high astigmatisms.METHODS:In a cross-sectional study,sampling was done from in different geographic regions in Iran using a multistage random cluster sampling method.All study participants underwent cycloplegic auto-refraction and subjective refraction using the red-green test.RESULTS:In this study,277 eyes of 158 students aged 8 to 15y were analyzed.According to the results,the mean difference between subjective refraction and autorefraction in measuring sphere,cylinder,spherical equivalent,J0,and J45 was-0.18±0.76,-0.36±0.40,-0.36±0.79,0.15±0.20,and 0.05±0.21 respectively.The correlation of these two refraction methods in measuring the aforementioned indices was 0.963,0.898,0.960,0.931,and 0.948 respectively.The 95%limits of agreement of the two methods in measuring the above indices were-1.66 to 1.31,-1.14 to 0.42,-1.91 to 1.19,-0.24 to 0.54,and-0.36 to 0.47 respectively.The agreement between the two methods decreased with increasing cylinder power,and the best agreement was found in myopic individuals.CONCLUSION:The measurements obtained by autorefractometer have a significantly higher cylinder average compared to subjective refraction.However,in the cylinder range of 4–5 diopters,the values of J0 and J45 do not have a high correlation.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2023YFB3811400 and 2022YFB3806000)the National Natural Science Foundation of China(Grant No.12074314)+1 种基金the Science and Technology New Star Program of Shaanxi Province,China(Grant No.2023KJXX-148)the Fundamental Research Funds for the Central Universities。
文摘The emergent metagrating,with its unique and flexible beam shaping capabilities,offers new paths to efficient modulation of acoustic waves.In this work,an acoustic metagrating is demonstrated for high-efficiency and wide-angle anomalous refraction.It is shown that the normal reflection and transmission can be totally suppressed by properly modulating the amplitude and phase characteristics of the metagrating supercells for high-efficiency anomalous refraction.The anomalous refraction behavior is achieved in the wide range of incident angles from 28°to 78°,and the efficiency of-1st order diffraction is higher than 90%by finely designing the metagrating structure.The anomalous refraction behaviors are verified experimentally at incidence angle of 28°,45°,and 78°,respectively.The demonstrated metagrating is anticipated to possess efficient wide-angle composite wavefront engineering applications in such fields as communications.
文摘Ocular biological characteristics and refractive errors in children with unilateral congenital ptosis Yu-Ying Sun,Bing-Ying Lin,Zhen Mao,Xuan-Wei Liang,Cui-Yu Zhang,Dan-Ping Huang,Yao Ni,Zuo-Hong Li Int J Ophthalmol 2025;18(4):691-698.DOI:10.18240/ijo.2025.04.16 The author requests to change the authorship and affiliations as follows.
基金Supported by Health and Family Planning Commission of Jiangxi Province(No.20131080)
文摘AIM: To report the visual outcomes and refractive status in premature infants with and without retinopathy of prematurity(ROP) who were or not treated. METHODS: The clinical records of all premature infants with or without ROP and with or without treatment between 2007 and 2017 were retrospectively reviewed. Basic demographic data, serial changes in ROP incidence, treatment and outcomes, and the refractive states were analyzed. Correlations among myopia and astigmatism progression, birth weight, gestational age, and treatment methods were also analyzed.RESULTS: A total of 562 screened premature infants(all Chinese, 1124 eyes), were recruited with a 378:184 maleto-female ratio. Birth weight did not directly influence ROP incidence. The overall ROP incidence was 16.55%(93/562 cases). The incidences in boys and girls were 16.14%(33/378 cases) and 17.39%(32/184 cases), respectively, and this difference was not significant. However, all infants with serious ROP(stage IV and V) were male. Myopia combined with astigmatism was common in premature infants with and without ROP(30.99%, 172/555 cases), and myopic refraction(including myopia and myopia combined with astigmatism) was more common in premature infants with ROP(48.84%, 42/86 cases). In the >8.00 diopter group, there were significantly more ROP infants than without ROP. Myopic refraction(including myopia and myopia combined with astigmatism) was most common in infants with ROP after treatment(63.63%, 7/11 cases). CONCLUSION: The refractive state is different between premature infants and mature infants. Those treated for ROP had a higher chance of developing myopia, astigmatism, and higher diopter.
文摘AIM: To compare the results of noncycloplegic photorefraction, cycloplegic photorefraction and cycloplegic refraction in preschool and non-verbal children.METHODS: One hundred and ninety-six eyes of 98children(50 females, 48 males) were included in the study. Firstly, non-cycloplegic photorefraction was achieved with Plusoptix A09; secondly, cycloplegic photorefraction was carried out with Plusoptix A09 after10 min cyclopentolate. Finally, 30 min after instillation of twice cyclopentolate, cycloplegic refraction was obtained with autorefraction and/or standard retinoscopy. Spheric equivalent, spheric power, cylindric power and cylindrical axis measurements were statistically compared.RESULTS: The mean age was 28.8±18.5mo(range12-72mo). The differences in spherical equivalent, spheric power and cylindrical power measured by the three methods were found statistically significant(P 【0.05).The spherical equivalent and spheric power measured by cycloplegic photorefraction were statistically higher than the measurements of the other methods(P 【0.05). The cylindrical power measured by cycloplegic refraction was statistically lower than the measurements of the photorefraction methods(P 【0.05). There was no significant difference in cylindrical axis measurements between three methods(P 】0.05).CONCLUSION: For the determination of refractive errors in children, the Plusoptix A09 measurements give incorrect results after instillation of cyclopentolate.Additionally, the cylindrical power measured by Plusoptix A09 with or without cycloplegia is higher. However, the non-cycloplegic Plusoptix A09 measures spheric equivalent and spheric power similar to cycloplegic refraction measurements in preschool and non-verbal children.
基金supported by grants from the National Natural Science Foundation of China(Nos.61751302,62003017,61627810,61833013,61973012)Science and Technology Key Innovative Project of Hangzhou,China(No.20182014B06)。
文摘Underwater navigation system is an indispensable part for autonomous underwater vehicles.Due to the indiscernibility of satellite signal,however,the underwater navigation problem is quite challenging,and a satellite-free navigation scheme should be looked for.Polarization navigation,inspired by insects’capability of autonomous homing and foraging,is an alternative solution to satellite navigation with great application potential.Underwater polarization provides an indirect sun compass to animals for orientation determination.However,it is difficult to apply terrestrial solar-tracking methodologies in underwater situations due to the refraction of polarized skylight at the air–water interface.To resolve this issue,an underwater solar-tracking algorithm is developed based on the underwater refraction-polarization pattern inside the Snell’s window.By employing Snell’s law and Fresnel refraction formula to decouple the refractive ray bending and polarization deflection,the celestial polarization pattern is obtained based on underwater measurement.To further improve the accuracy,the degree of polarization is employed as a weight factor for E-vector.A long-lasting underwater experiment was conducted to validate the effectiveness of the proposed approach,and the results showed the root-mean-square errors of solar zenith and azimuth employing this algorithm were 0.3°and 1.3°,respectively.Our experimental results show that the refraction-polarization pattern inside the Snell’s window exhibits immense potential to improve the solar-tracking accuracy for underwater navigation.
文摘BACKGROUND Myopia,as one of the common ocular diseases,often occurs in adolescence.In addition to the harm from itself,it may also lead to serious complications.Thus,prevention and control of myopia are attracting more and more attention.Previous research revealed that single-focal glasses and orthokeratology lenses(OK lenses)played an important part in slowing down myopia and preventing high myopia.AIM To compare the clinical effects of OK lenses and frame glasses against the increase of diopter in adolescent myopia and further explore the mechanism of the OK lens.METHODS Changes in diopter and axial length were collected among 70 adolescent myopia patients(124 eyes)wearing OK lenses for 1 year(group A)and 59 adolescent myopia patients(113 eyes)wearing frame glasses(group B).Refractive states of their retina were inspected through multispectral refraction topography.The obtained hyperopic defocus was analyzed for the mechanism of OK lenses on slowing down the increase of myopic diopter by delaying the increase of ocular axis length and reducing the near hyperopia defocus.RESULTS Teenagers in groups A and B were divided into low myopia(0 D--3.00 D)and moderate myopia(-3.25 D--6.00 D),without statistical differences among gender and age.After 1-year treatment,the increase of diopter and axis length and changes of retinal hyperopic defocus amount of group A were significantly less than those of group B.According to the multiple linear analysis,the retinal defocus in the upper,lower,nasal,and temporal directions had almost the same effect on the total defocus.The amount of peripheral retinal defocus(15°-53°)in group A was significantly lower than that in group B.CONCLUSION Multispectral refraction topography is progressive and instructive in clinical prevention and control of myopia.
基金Supported by National Natural Science Foundation of China(No.81800854)Joint Innovation Project of National Defense Technology Innovation Zone(No.20-163-15-ZT-001-001-10)Efficiency Improvement Project of Air Force Medical University(No.2021HKYX24)。
文摘AIM:To characterize peripheral refraction and its relationship with myopia development in a selected group of male teenage Chinese students.METHODS:This 2-year prospective cohort study randomly enrolled 85 non-myopic boys(age,14-16 y)from the Experimental Class of Air Force in China.Cycloplegic peripheral refraction was examined at 0°,±10°,and±20°along the horizontal visual field in the right eye at the baseline and 2-year follow-up.RESULTS:The incidence of myopia at the 2-year followup was 15.29%(13/85).The baseline central refraction(CR)and peripheral refraction at±10°were significantly lower in students who developed myopia than in those who did not(P<0.05).Relative peripheral refraction(RPR)did not differ between students with and without myopia(P>0.05).At the 2-year follow-up,the RPR at±10°and 20°nasal was significantly more hyperopic in the myopic group than in the non-myopic group.Multiple linear regression analysis indicated that the change in CR was significantly correlated with the changes in RPR at 20°nasal,10°nasal,and 20°temporal.Multivariate Logistic regression analysis indicated that the baseline CR[odds ratio(OR):0.092,95%confidence interval(CI):0.012-0.688,P=0.020]and the baseline RPR at 10°nasal(OR:0.182,95%CI:0.042-0.799,P=0.024)were significantly correlated with incident myopia(Omnibus test,χ=10.20,P=0.006).CONCLUSION:CR change is significantly correlated with changes in RPR,and students who develop myopia have more relative peripheral hyperopia.More baseline CR and relative peripheral hyperopia at 10°nasal are protective of myopia onset.
基金supported by the National Natural Science Foundation of China (No.11002008)funded in part by Ministry of Science and Technology of China (No.2014CB845303)
文摘Autonomous orbit determination via integration of epoch-differenced gravity gradients and starlight refraction is proposed in this paper for low-Earth-orbiting satellites operating in GPSdenied environments. Starlight refraction compensates for the significant along-track position error that occurs from only using gravity gradients and benefits from integration in terms of improved accuracy in radial and cross-track position estimates. The between-epoch differencing of gravity gradients is employed to eliminate slowly varying measurement biases and noise near the orbit revolution frequency. The refraction angle measurements are directly used and its Jacobian matrix derived from an implicit observation equation. An information fusion filter based on a sequential extended Kalman filter is developed for the orbit determination. Truth-model simulations are used to test the performance of the algorithm, and the effects of differencing intervals and orbital heights are analyzed. A semi-simulation study using actual gravity gradient data from the Gravity field and steady-state Ocean Circulation Explorer（GOCE） combined with simulated starlight refraction measurements is further conducted, and a three-dimensional position accuracy of better than 100 m is achieved.
文摘AIM:To investigate the differences in retinal refraction difference values(RDVs)of adult patients with myopic anisometropia compared with those without myopic anisometropia,and to investigate the relationship between ocular biometric measurements and relative peripheral refraction.METHODS:This clinical observation study included 130 patients with myopia(-0.25 to-10.00 D)between October 2022 and January 2023 aged between 18 and 40y.The patients were divided into anisometropia(n=63;difference in binocular anisometropia≥1.00 D)and non-anisometropia(n=67;difference in binocular anisometropia<1.00 D)groups accordingly.Ocular biometric measurements were performed by optical biometrics and corneal topography to assess the steep keratometry(Ks),flap keratometry(Kf),axial length(AL),corneal astigmatism(CYL;Ks-Kf),surface regularity index(SRI),surface asymmetry index(SAI),and central corneal thickness(CCT).The RDV was measured at five retinal areas from the fovea to 53 degrees(RDV-0-10,RDV-10-20,RDV-20-30,RDV-30-40,and RDV-40-53),the total RDV(TRDV)of 53 degrees,and four regions,including RDV-superior,RDV-inferior,RDV-temporal,and RDV-nasal.An analysis of Spearman correlation was carried out to examine the correlation between RDV and the spherical equivalent(SE)and ocular biological parameters.RESULTS:Within RDV-20-53,both groups showed relative hyperopic defocus,and the increase in RDV corresponds to the increase in eccentricity.In the myopic anisometropia group,the TRDV,RDV-20-53,RDV-superior,and more myopic eyes had significantly higher RDVtemporal values than less myopic eyes.(P<0.05).In the non-anisometropia group,there was no significant difference in the RDV between the more and less myopic eyes at different eccentricities(P>0.05).There was a negative correlation between SE and TRDV(r=-0.205,P=0.001),RDV-20-53(r=-0.281,-0.183,-0.176,P<0.05),RDV-superior(r=-0.251,P<0.001),and RDV-temporal(r=-0.230,P<0.001),a negative correlation between CYL and RDV-10-30(r=-0.147,-0.180,P<0.05),and a negative correlation between SRI and RDV-0-20(r=-0.190,-0.170,P<0.05).AL had a positive correlation with RDV-20-30(r=0.164,P=0.008)and RDV-temporal(r=0.160,P=0.010).CONCLUSION:More myopic eyes in patients with myopic anisometropia show more peripheral hyperopic defocus.Diopter and corneal morphology may affect peripheral retinal defocus.
基金Project supported by the Council of Scientific and Industrial Research (CSIR) of New Delhi(Nos. 09/105(0169)/2008-EMR-I and 09/105(0185)/2009-EMR-I)
文摘The propagation of elastic waves is studied in a porous solid saturated with two immiscible viscous fluids. The propagation of three longitudinal waves is represented through three scalar potential functions. The lone transverse wave is presented by a vector potential function. The displacements of particles in different phases of the aggregate are defined in terms of these potential functions. It is shown that there exist three longitudinal waves and one transverse wave. The phenomena of reflection and refraction due to longitudinal and transverse waves at a plane interface between an elastic solid half-space and a porous solid half-space saturated with two immiscible viscous fluids are investigated. For the presence of viscosity in pore-fluids, the waves refracted to the porous medium attenuate in the direction normal to the interface. The ratios of the amplitudes of the reflected and refracted waves to that of the incident wave are calculated as a non- singular system of linear algebraic equations. These amplitude ratios are used to further calculate the shares of different scattered waves in the energy of the incident wave. The modulus of the amplitude and the energy ratios with the angle of incidence are computed for a particular numerical model. The conservation of the energy across the interface is verified. The effects of variations in non-wet saturation of pores and frequencies on the energy partition are depicted graphically and discussed,
文摘A numerical model based on the mild-slope equation of water wave propagation over complicated bathymetry,taking into account the combined effects of refraction,diffraction and dissipation due to wavebreaking is presented.Wave breaking is simulated by modifying the wave height probability density func-tion and the wave energy dissipation mechanism is parameterized according to that of the hydraulic jumpformulation.Solutions of the wave height,phase function,and the wave direction at every grid point areobtained by finite difference approximation of the governing equations,using Gauss-Seidel Iterative Method(GSIM)row by row.Its computational convenience allows it to be applied to large coast regions tostudy the wave transformation problem.Several case studies have been made and the results compare verywell with the experiment data and other model solutions.The capability and utility of the model forreal coast areas are illustrated by application to a shallow bay of northeast Australia.
文摘Sinkholes and cavities can represent serious hazards to human safety and urban infrastructures,cause roadbed subsidence,and so on.It is therefore essential to evaluate various sinkholes in different depths and sizes to assess the risk of collapse.This paper evaluates the effect of different cavities on Rayleigh-wave propagation and body(P)wave refraction.Rayleigh(R)wave propagation is analyzed according to the classical multi-channel analysis of surface waves(MASW)method also considering the R-wave backscattering.Synthetic seismic traces are computed by means of finite element modeling(FEM)for cavity and intrusion at different depths and sizes.Furthermore,field acquisition data is used to verify the detection effect of a cavity on R-and P-waves.The results show that the presence of backscattered R-waves and the changes in the R-wave velocity spectrum can help in cavity identification.Additional possible evidence is represented by significant changes in the refraction travel times over the cavity location.It can be concluded that the field data are in good agreement with the synthetic,and it could be effective to consider the results of both R-and P-wave analysis in order to efficiently identify the cavities.
