AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 childr...AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 children(252 eyes)with myopia and HAL treatment who were aged 7-13 and had rapid AL changes.The participants were divided into groups with AL reduction and elongation according to the changes in AL within 6mo.Paired t-tests were used to compare the ocular biological parameters at baseline and after rapid changes post-HAL treatment.Pearson’s correlation analysis was used to determine the association between the ocular parameters and AL changes.RESULTS:The ocular biological parameters significantly changed in the children with myopia and rapid AL changes after HAL treatment.In the group with AL reduction,the anterior chamber depth(ACD)and vitreous chamber depth(VCD)decreased.The crystalline lens thickness(CLT)increased,corneal flat keratometry(FK)decreased,and steep keratometry(SK)increased(all P<0.001).The eyes in the group with AL elongation had increased ACD and VCD and steepened SK,but the CLT or FK findings were not different.AL change was negatively associated with baseline astigmatism(r=-0.171;P=0.007).CONCLUSION:In the eyes with HAL treatment,decreased ACD and VCD,thickened CLT,flattened FK,and steepened SK are observed during AL reduction.Lower baseline astigmatism is associated with AL reduction.The AL reduction may suggest the potential efficacy of HAL intervention in myopia control,while providing evidence for optimizing personalized myopia management strategies.Further longitudinal studies are warranted to validate whether rapid AL changes predict sustained treatment efficacy.展开更多
A set-up based on a special shadow method, pinhole method, was made and some experiments were done. The results show that this novel method is simple, easy to operate,and suitable for testing large aspherical surfaces...A set-up based on a special shadow method, pinhole method, was made and some experiments were done. The results show that this novel method is simple, easy to operate,and suitable for testing large aspherical surfaces quantitatively.展开更多
In order to resolve the problems of machining non-axisymmetric aspheric lens,which is short of flexibility in mould grinding and needs high accuracy CNC machine center in globediamond wheel grinding, a new parallel gr...In order to resolve the problems of machining non-axisymmetric aspheric lens,which is short of flexibility in mould grinding and needs high accuracy CNC machine center in globediamond wheel grinding, a new parallel grinding method that utilizes common arc diamond wheel isput forward. Base on the approach calculation of machining locus, the advantages of parallelgrinding that machines non-axisymmetric aspheric lens by 2.5-axis CNC machine center have beenobtained. The results of grinding experiment show the new method can meet the need of grinding highaccuracy non-axisymmetric aspheric lens.展开更多
AIM： To evaluate the impact of spherical and aspherical intraocular lenses on the postoperative visual quality of age-related cataract patients using Optical Quality Analysis System （OQAS）. METHODS： Seventy-four ...AIM： To evaluate the impact of spherical and aspherical intraocular lenses on the postoperative visual quality of age-related cataract patients using Optical Quality Analysis System （OQAS）. METHODS： Seventy-four eyes with age-related cataracts were randomly divided into spherical and aspherical lens implantation groups. Best-corrected visual acuity （BCVA） was measured preoperatively, one day, one week, two weeks, one month and two months after surgery. A biometric systems analysis using the OQAS objective scattering index （OSI） was performed. RESULTS： There were no significant differences in visual acuity （P〉0.05） before and after spherical and aspheric lens implantation. There was a negative linear correction between the OSI value and BCVA （t-=-0.634, P=-0.000）, and positive corrections between the OSI value and the lens LOCUS III value of nucleus color （NC）, nucleus opacity （NO）, cortex （C） and posterior lens capsular （P） （r=0.704, P=0.000; r=0.514, P=0.000; r=0.276, P=0.020; r=0.417, P=-0.000, respectively）. OSI values of spherical vs aspherical lenses were 11.5±3.6 vs 11.8±3.4, 4.1±0.9 vs 3.3±0.8, 3.5±0.9 vs 2.7±0.7, 3.3±0.8 vs 2.6±0.7, 3.2±0.7 vs 2.5±0.8, and 3.2±0.8 vs 2.50.8 before and ld, 1, 2wk, 1 and 2mo after surgery, respectively. All time points varied significantly （P〈0.01） between the two groups. CONCLUSION： Aspherical IOLs does not significantly affect visual acuity compared with spherical IOLs. The OSI value, was significantly lower in the aspherical lens group compared with the spherical lens. This study shows that objective visual quality of aspheric IOLs is better than that of the spherical lens by means of OQAS biological measurement method.展开更多
AIM:To compare the visual performance of pseudophakic eyes implanted with Al-UV and SN60WF aspheric intraocular lens(IOL),and to investigate the correlations between visual quality parameters and pupil size.METHODS:Th...AIM:To compare the visual performance of pseudophakic eyes implanted with Al-UV and SN60WF aspheric intraocular lens(IOL),and to investigate the correlations between visual quality parameters and pupil size.METHODS:This prospective comparative study included 105 eyes of 90 patients with age-related cataract who underwent uneventful phacoemulsification.The subjects were divided into two groups according to the implanted IOL type.Three months postoperatively,visual acuity and contrast sensitivity were measured,wave-front aberrations were assessed using a KR-IW aberrometer(Topcon),and objective optical quality parameters were performed using an optical quality analysis system-OQAS Il(Visiometrics).Independent sample Mest and Spearman correlation analysis were used for data analysis.RESULTS:There were no significant differences found in visual acuity,contrast sensitivity and visual quality parameters between the two groups(P>0.05).The measured intraocular spherical aberration(SA)in Al-UV IOL eyes of-0.19±0.05 pm was close to the designed SA value of-0.20 pm.The modulation transfer function cutoff,Strehl ratio and OQAS values were negatively correlated with pupil size in both groups(P<0.01).CONCLUSION:The subjective and objective visual quality in pseudophakic eyes with A1-UV and SN60WF IOLs are comparable.For aspheric IOL eyes,visual quality decreases with increasing pupil size.展开更多
In order to improve machining accuracy and efficiency, a software-controlled system of ultra-precision machining for axisymmetric aspheric mirror, using techniques of error compensation, remote transmission and modul...In order to improve machining accuracy and efficiency, a software-controlled system of ultra-precision machining for axisymmetric aspheric mirror, using techniques of error compensation, remote transmission and modularization, is designed based on industrial PC, Windows 2000 work platform and Visual Basic 6.0. By experiments, this system realizes functions of ultra-precision machining, machining error compensation, remote data transmission and automatic data transformation among first machining, compensation machining and accuracy measurement. The actual application shows that error compensation improves machining accuracy, remote transmission improves machining efficiency while modularization avoids repeated work and improves design efficiency. Therefore, the system has met ultra-precision machining need for aspheric mirror.展开更多
With the evolution of cataract surgery from visual rehabilitation to refractive surgery, aspheric intraocular lenses(IOLs) are being increasingly used in the field of ophthalmology. This increased use can be attribute...With the evolution of cataract surgery from visual rehabilitation to refractive surgery, aspheric intraocular lenses(IOLs) are being increasingly used in the field of ophthalmology. This increased use can be attributed to negative or zero spherical aberrations with unique optical designs, which counteract some of the positive spherical aberrations of the cornea. These alterations reduce the total spherical aberration of human eyes and improve the visual acuity in patients with cataract postoperatively. At present, various types of aspheric IOLs are used worldwide. Although the implantation of aspheric IOL is beneficial to the patients who need correction of spherical aberrations, much controversy is still associated with ocular residual spherical aberrations that facilitate the best visual quality for patients postoperatively. In order to provide reference for future clinical work and scientific research, this report reviews the relationship between the ocular residual spherical aberration of human eyes and visual quality.展开更多
Structure design and fabricating methods of three-dimensional （3D） artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial c...Structure design and fabricating methods of three-dimensional （3D） artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes （ACEs） are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye （ACE） with surface roughness （Ra） below 0.12 p.m is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.展开更多
AIM: To compare higher order aberrations in two aspherical intraocular lenses(IOLs): Akreos advanced optics(AO) and Dr. Schmidt Microcrystalline 6125 aspheric anterior surface(MC6125AS) with each other. METHODS: Forty...AIM: To compare higher order aberrations in two aspherical intraocular lenses(IOLs): Akreos advanced optics(AO) and Dr. Schmidt Microcrystalline 6125 aspheric anterior surface(MC6125AS) with each other. METHODS: Forty eyes of 39 patients underwent phacoemulsification and Akreos AO and MC6125 AS were implanted in their eyes in a random manner. Three months post-operatively, higher order aberrations including spherical aberration, coma aberration, and total aberrations were measured and compared.RESULTS: The total aberration was 0.24±0.17 in eyes with Dr. Schmidt and 0.20 ±0.01 in eyes with Akreos AO(P =0.361). The mean of coma aberration was 0.17 ±0.21 and 0.09 ±0.86 in Dr. Schmidt and Akreos lenses,respectively(P =0.825). Total spherical aberration was almost the same in both groups(mean: 0.05, P =0.933).Best corrected visual acuity in Akreos AO(0.10±0.68) and Dr. Schmidt(0.09±0.67) did not differ significantly(P =0.700). CONCLUSION: There is no statistically significant difference in the higher order aberrations between these two aspherical lenses.展开更多
Objective: To compare patient-reported outcomes after implantation of the ZA9003 intraocular lens(IOLs), or the MCX11 ASP IOLs or the spherical IOLs(HQ-201HEP). Methods: Prospective nonrandomized controlled trial was ...Objective: To compare patient-reported outcomes after implantation of the ZA9003 intraocular lens(IOLs), or the MCX11 ASP IOLs or the spherical IOLs(HQ-201HEP). Methods: Prospective nonrandomized controlled trial was used. A total of 105 patients(210 eyes) were divided into three groups according to the type of IOLs: ZA9003(35 patients, 70 eyes), MCX11 ASP(35 patients, 70 eyes) or HQ-201HEP(35 patients, 70 eyes). The main outcome was scores of Catquest nine-item short-form questionnaire. Additional outcome was best corrected visual acuities, spherical aberration(SA) and total higher-order aberrations(HOAs). Results: The global score was significantly lower in the spherical IOL group than the aspherical IOL group of-020 μm SA(P < 0.05) and the aspherical IOL group of-027 μm SA(P < 0.05), and no significant difference was found in the global score between the aspherical IOL group of-020 μm SA than the aspherical IOL group of-027 μm SA(P > 0.05). Significant differences were also found in question 2, question 5, question 6 and question 8 between the spherical IOLs and the aspherical IOLs. Conclusion: Implantation of an aspherical IOL could improve vision-related quality of life compared with a spherical IOL. However, there were no statistically significant differences in vision-related quality of life between aspheric IOLs with different negative spherical aberrations.展开更多
AIM： To evaluate the visual, refractive and corneal asphericity changes after intrastromal corneal ring segment（ICRS） implantation for visual rehabilitation of keratoconus.METHODS： A total of 42 eyes of 32 patient...AIM： To evaluate the visual, refractive and corneal asphericity changes after intrastromal corneal ring segment（ICRS） implantation for visual rehabilitation of keratoconus.METHODS： A total of 42 eyes of 32 patients were included. After creation of intrastromal tunnels of 5.01±0.03 mm inner diameter, 5.71±0.03 mm outer diameter and at 384.21±34.12 μm depth, 1 or 2 ICRS of 150-300 μm thickness and 90°-210° arc length were implanted. Changes in uncorrected distance visual acuity（UDVA）, corrected distance visual acuity（CDVA）, refractive errors, mean simulated keratometry readings SimK_（avg）, anterior and posterior corneal asphericity values（Q_（ant） and Q_（post）, respectively） measured with Scheimpflug topography were evaluated retrospectively. RESULTS： There was a significant improvement in UDVA and CDVA, along with a significant decrease in refractive spherical equivalent（SE）, cylinder and SimK_（avg） postoperatively（P〈0.001 for all）. Mean Qant increased from-1.06±0.48 to-0.57±0.58 postoperatively（P〈0.001）. Change in mean Qpost was insignificant（P=0.92）. Postoperative changes in UDVA and CDVA were not correlated with the postoperative changes in SE and cylinder（P〉0.05 for all）; but were correlated with the preoperative SimK_（avg） and Q_（ant） values（P〈0.001 for all）. CONCLUSION： ICRS implantation seems to approximate the anterior corneal asphericity of ＂advanced prolate＂ shape to ＂optimal prolate＂ shape and an ＂ideal Q value＂ of-0.46; which may have a role in improved UDVA and CDVA postoperatively, besides decreased refractive cylinder values.展开更多
In order to produce the high quality optical aspheric lens,the shrinkage of lens should be strictly controlled during the injection process.Serials of experiments are done to find the factors that affect the lens shri...In order to produce the high quality optical aspheric lens,the shrinkage of lens should be strictly controlled during the injection process.Serials of experiments are done to find the factors that affect the lens shrinkage during the injection molding process.The study is focused on the effect of gate size,packing time and pressure on the shrinkage.The gate size decides the effective packing time.Only when the effective packing time is enough,the shrinkage size will be decreased along with the packing pressure increased.However the packing time is determined by the gate size.But big gate size is not easily to be cut and the cutting difficulty will cause the part quality problems.The experiments show that packing pressure not only determines the part shrinkage size and also affects the part shrinkage uniformity.When the packing pressure is more than a critical one,the effect of packing pressure on the shrinkage size becomes smaller.And the shrinkage uniformity is guaranteed.展开更多
Precision grinding is a key process for realizing the use of large-aperture aspherical optical elements in laser nuclear fusion devices,large-aperture astronomical telescopes,and high-resolution space cameras.In this ...Precision grinding is a key process for realizing the use of large-aperture aspherical optical elements in laser nuclear fusion devices,large-aperture astronomical telescopes,and high-resolution space cameras.In this study,the arc envelope grinding process of large-aperture aspherical optics is investigated using a CM1500 precision grinding machine with a maximum machinable diameter ofΦ1500 mm.The form error of the aspherical workpiece induced by wheel setting errors is analytically modeled for both parallel and cross grinding.Results show that the form error is more sensitive to the wheel setting error along the feed direction than that along the lateral direction.It is a bilinear function of the feed-direction wheel setting error and the distance to the optical axis.Based on the error function above,a method to determine the wheel setting error is proposed.Subsequently,grinding tests are performed with the wheels aligned accurately.Using a newly proposed partial error compensation method with an appropriate compensation factor,a form error of 3.4μm peak-to-valley(PV)for aΦ400 mm elliptical K9 glass surface is achieved.展开更多
AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles.METHODS: A total of 40 eyes of 40 patients with a mean a...AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles.METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1 y were included. In all cases, a corneal curvature analysis was performed with IOL-Master(IOLM), iDesign 2(ID2), and Sirius systems(SIR). Differences between instruments for flattest(K1) and steepest(K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity(Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21(P<0.001),-0.12±0.36(P=0.046) and-0.32±0.36 D(P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33(P<0.001),-0.08±0.43(P=0.265) and-0.39±0.38 D(P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance(0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis(26.68o, 33.83o and 18.37o, P≥0.121) and for Q between SIR and ID2(0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provideby the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.展开更多
With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i n...With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i ncreased rapidly in the recent years. The key technologies of fabrication of asp heric plastic lens are the design and manufacturing moulds, selection of proper injection moulding equipment, and optimization of injection moulding parameters etc. In this paper, the effect of injection pressure, moulding temperature, cool ing time and injection speed on the surface profile of the lenses during injecti on and holding process is investigated. Surface quality of plastic lenses is mea sured by Talysurf Texture Measuring System. The experimental results showed that the injection pressure and moulding temperature are important parameters compar ing to cooling time and injection speed. A bit change of injection pressure or m oulding temperature will affect the property of the surface profile. Either incr easing injection pressure or mould temperature can achieve less shrinkage. Other wise, a lower injection pressure will produce more shrinkage, more air traps and a lower mould temperature results greater warp and higher shrinkage. The dynami c process of injection for optical plastic lenses is simulated by 3D Moldflow pl astic Insight software (MPI). The MPI will help us to optimize injection mouldin g parameters.展开更多
The shape asymmetry of gaussian models of linear and circular macromolecules has been numerically investigated in terms of asphericity and prolateness parameters. These parameters are found to decrease with increasing...The shape asymmetry of gaussian models of linear and circular macromolecules has been numerically investigated in terms of asphericity and prolateness parameters. These parameters are found to decrease with increasing length for the macromolecule either confined to a plane or in three dimensions. The effect of dimensionality on these parameters is visible only for low dimensions and is generally weak. As dimensionality goes to infinity, it is found that asphericity and prolateness for both chains and rings approach slowly yet descendingly values of corresponding asphericity and prolateness factors, with the exception of the chain which shows a minimum value of asphericity when the embedding space has a dimensionality of four.展开更多
Design method and procedures of computer-generated hologram （CGH） used for aspheric test are in- troduced in detail. For CGH phase calculation, virtual medium which has zero refractive index at given wavelength is u...Design method and procedures of computer-generated hologram （CGH） used for aspheric test are in- troduced in detail. For CGH phase calculation, virtual medium which has zero refractive index at given wavelength is used to model ideal aspheric wavefront. Reflective Fresnel zones located in a ring area concentric to the CGH structure is designed to reduce or eliminate alignment errors. Substrate figure error, pattern distortion, etching and duty cycle variations that influence the reconstructed wavefront are quantitatively analyzed in theory and corresponding error equations are obtained to guide the tolerance distribution during CGH fabricating. A design example is given and the uncertainty of t achieves λ20.展开更多
According to the theory of testing aspherical surface by normal aberration compensation method,the designing method of quasi-universal compensator is studied.On the basis of third-order aberration theory,after calcula...According to the theory of testing aspherical surface by normal aberration compensation method,the designing method of quasi-universal compensator is studied.On the basis of third-order aberration theory,after calculating and optimizing with an optical design program,the structure parameters of a compensator are obtained.This new compensator could be used in Twyman-Green interferometer,and in measurement of a certain range of paraboloid ellipsoid and hyperboloid.The compensation accuracy is more than 0.02 λ .展开更多
The original idea and shaping principle of locus shaping method for processing the aspheric optical parts are introduced, and the partial structure of the machine tool designed is described. The method has the advanta...The original idea and shaping principle of locus shaping method for processing the aspheric optical parts are introduced, and the partial structure of the machine tool designed is described. The method has the advantage of high efficiency and low cost compared to the numerical control method. And it is proven that the method is feasible.展开更多
基金Supported by the Medical Science and Technology Project of Zhejiang Province of China(No.2020KY191).
文摘AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 children(252 eyes)with myopia and HAL treatment who were aged 7-13 and had rapid AL changes.The participants were divided into groups with AL reduction and elongation according to the changes in AL within 6mo.Paired t-tests were used to compare the ocular biological parameters at baseline and after rapid changes post-HAL treatment.Pearson’s correlation analysis was used to determine the association between the ocular parameters and AL changes.RESULTS:The ocular biological parameters significantly changed in the children with myopia and rapid AL changes after HAL treatment.In the group with AL reduction,the anterior chamber depth(ACD)and vitreous chamber depth(VCD)decreased.The crystalline lens thickness(CLT)increased,corneal flat keratometry(FK)decreased,and steep keratometry(SK)increased(all P<0.001).The eyes in the group with AL elongation had increased ACD and VCD and steepened SK,but the CLT or FK findings were not different.AL change was negatively associated with baseline astigmatism(r=-0.171;P=0.007).CONCLUSION:In the eyes with HAL treatment,decreased ACD and VCD,thickened CLT,flattened FK,and steepened SK are observed during AL reduction.Lower baseline astigmatism is associated with AL reduction.The AL reduction may suggest the potential efficacy of HAL intervention in myopia control,while providing evidence for optimizing personalized myopia management strategies.Further longitudinal studies are warranted to validate whether rapid AL changes predict sustained treatment efficacy.
文摘A set-up based on a special shadow method, pinhole method, was made and some experiments were done. The results show that this novel method is simple, easy to operate,and suitable for testing large aspherical surfaces quantitatively.
基金This project is supported by Provincial Foundation for Young Scientists & Scholars Innovation of Fujian, China (No.0013K13004).
文摘In order to resolve the problems of machining non-axisymmetric aspheric lens,which is short of flexibility in mould grinding and needs high accuracy CNC machine center in globediamond wheel grinding, a new parallel grinding method that utilizes common arc diamond wheel isput forward. Base on the approach calculation of machining locus, the advantages of parallelgrinding that machines non-axisymmetric aspheric lens by 2.5-axis CNC machine center have beenobtained. The results of grinding experiment show the new method can meet the need of grinding highaccuracy non-axisymmetric aspheric lens.
文摘AIM： To evaluate the impact of spherical and aspherical intraocular lenses on the postoperative visual quality of age-related cataract patients using Optical Quality Analysis System （OQAS）. METHODS： Seventy-four eyes with age-related cataracts were randomly divided into spherical and aspherical lens implantation groups. Best-corrected visual acuity （BCVA） was measured preoperatively, one day, one week, two weeks, one month and two months after surgery. A biometric systems analysis using the OQAS objective scattering index （OSI） was performed. RESULTS： There were no significant differences in visual acuity （P〉0.05） before and after spherical and aspheric lens implantation. There was a negative linear correction between the OSI value and BCVA （t-=-0.634, P=-0.000）, and positive corrections between the OSI value and the lens LOCUS III value of nucleus color （NC）, nucleus opacity （NO）, cortex （C） and posterior lens capsular （P） （r=0.704, P=0.000; r=0.514, P=0.000; r=0.276, P=0.020; r=0.417, P=-0.000, respectively）. OSI values of spherical vs aspherical lenses were 11.5±3.6 vs 11.8±3.4, 4.1±0.9 vs 3.3±0.8, 3.5±0.9 vs 2.7±0.7, 3.3±0.8 vs 2.6±0.7, 3.2±0.7 vs 2.5±0.8, and 3.2±0.8 vs 2.50.8 before and ld, 1, 2wk, 1 and 2mo after surgery, respectively. All time points varied significantly （P〈0.01） between the two groups. CONCLUSION： Aspherical IOLs does not significantly affect visual acuity compared with spherical IOLs. The OSI value, was significantly lower in the aspherical lens group compared with the spherical lens. This study shows that objective visual quality of aspheric IOLs is better than that of the spherical lens by means of OQAS biological measurement method.
基金Supported by Project of Science&Technology Department of Sichuan Province(No.2019YJ0381)Key Project of Sichuan Health and Family Planning Commission(No.18ZD022).
文摘AIM:To compare the visual performance of pseudophakic eyes implanted with Al-UV and SN60WF aspheric intraocular lens(IOL),and to investigate the correlations between visual quality parameters and pupil size.METHODS:This prospective comparative study included 105 eyes of 90 patients with age-related cataract who underwent uneventful phacoemulsification.The subjects were divided into two groups according to the implanted IOL type.Three months postoperatively,visual acuity and contrast sensitivity were measured,wave-front aberrations were assessed using a KR-IW aberrometer(Topcon),and objective optical quality parameters were performed using an optical quality analysis system-OQAS Il(Visiometrics).Independent sample Mest and Spearman correlation analysis were used for data analysis.RESULTS:There were no significant differences found in visual acuity,contrast sensitivity and visual quality parameters between the two groups(P>0.05).The measured intraocular spherical aberration(SA)in Al-UV IOL eyes of-0.19±0.05 pm was close to the designed SA value of-0.20 pm.The modulation transfer function cutoff,Strehl ratio and OQAS values were negatively correlated with pupil size in both groups(P<0.01).CONCLUSION:The subjective and objective visual quality in pseudophakic eyes with A1-UV and SN60WF IOLs are comparable.For aspheric IOL eyes,visual quality decreases with increasing pupil size.
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program, No.2004AA8042111)Program for "IRTXMU".
文摘In order to improve machining accuracy and efficiency, a software-controlled system of ultra-precision machining for axisymmetric aspheric mirror, using techniques of error compensation, remote transmission and modularization, is designed based on industrial PC, Windows 2000 work platform and Visual Basic 6.0. By experiments, this system realizes functions of ultra-precision machining, machining error compensation, remote data transmission and automatic data transformation among first machining, compensation machining and accuracy measurement. The actual application shows that error compensation improves machining accuracy, remote transmission improves machining efficiency while modularization avoids repeated work and improves design efficiency. Therefore, the system has met ultra-precision machining need for aspheric mirror.
文摘With the evolution of cataract surgery from visual rehabilitation to refractive surgery, aspheric intraocular lenses(IOLs) are being increasingly used in the field of ophthalmology. This increased use can be attributed to negative or zero spherical aberrations with unique optical designs, which counteract some of the positive spherical aberrations of the cornea. These alterations reduce the total spherical aberration of human eyes and improve the visual acuity in patients with cataract postoperatively. At present, various types of aspheric IOLs are used worldwide. Although the implantation of aspheric IOL is beneficial to the patients who need correction of spherical aberrations, much controversy is still associated with ocular residual spherical aberrations that facilitate the best visual quality for patients postoperatively. In order to provide reference for future clinical work and scientific research, this report reviews the relationship between the ocular residual spherical aberration of human eyes and visual quality.
基金Supported by National Natural Science Foundation of China(Grant No.50935003)National Numerical Control Major Projects of China(Grant No.2013ZX04001000215)
文摘Structure design and fabricating methods of three-dimensional （3D） artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes （ACEs） are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye （ACE） with surface roughness （Ra） below 0.12 p.m is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.
文摘AIM: To compare higher order aberrations in two aspherical intraocular lenses(IOLs): Akreos advanced optics(AO) and Dr. Schmidt Microcrystalline 6125 aspheric anterior surface(MC6125AS) with each other. METHODS: Forty eyes of 39 patients underwent phacoemulsification and Akreos AO and MC6125 AS were implanted in their eyes in a random manner. Three months post-operatively, higher order aberrations including spherical aberration, coma aberration, and total aberrations were measured and compared.RESULTS: The total aberration was 0.24±0.17 in eyes with Dr. Schmidt and 0.20 ±0.01 in eyes with Akreos AO(P =0.361). The mean of coma aberration was 0.17 ±0.21 and 0.09 ±0.86 in Dr. Schmidt and Akreos lenses,respectively(P =0.825). Total spherical aberration was almost the same in both groups(mean: 0.05, P =0.933).Best corrected visual acuity in Akreos AO(0.10±0.68) and Dr. Schmidt(0.09±0.67) did not differ significantly(P =0.700). CONCLUSION: There is no statistically significant difference in the higher order aberrations between these two aspherical lenses.
基金supported by the Health Bureau of Shanghai City(201440029)
文摘Objective: To compare patient-reported outcomes after implantation of the ZA9003 intraocular lens(IOLs), or the MCX11 ASP IOLs or the spherical IOLs(HQ-201HEP). Methods: Prospective nonrandomized controlled trial was used. A total of 105 patients(210 eyes) were divided into three groups according to the type of IOLs: ZA9003(35 patients, 70 eyes), MCX11 ASP(35 patients, 70 eyes) or HQ-201HEP(35 patients, 70 eyes). The main outcome was scores of Catquest nine-item short-form questionnaire. Additional outcome was best corrected visual acuities, spherical aberration(SA) and total higher-order aberrations(HOAs). Results: The global score was significantly lower in the spherical IOL group than the aspherical IOL group of-020 μm SA(P < 0.05) and the aspherical IOL group of-027 μm SA(P < 0.05), and no significant difference was found in the global score between the aspherical IOL group of-020 μm SA than the aspherical IOL group of-027 μm SA(P > 0.05). Significant differences were also found in question 2, question 5, question 6 and question 8 between the spherical IOLs and the aspherical IOLs. Conclusion: Implantation of an aspherical IOL could improve vision-related quality of life compared with a spherical IOL. However, there were no statistically significant differences in vision-related quality of life between aspheric IOLs with different negative spherical aberrations.
文摘AIM： To evaluate the visual, refractive and corneal asphericity changes after intrastromal corneal ring segment（ICRS） implantation for visual rehabilitation of keratoconus.METHODS： A total of 42 eyes of 32 patients were included. After creation of intrastromal tunnels of 5.01±0.03 mm inner diameter, 5.71±0.03 mm outer diameter and at 384.21±34.12 μm depth, 1 or 2 ICRS of 150-300 μm thickness and 90°-210° arc length were implanted. Changes in uncorrected distance visual acuity（UDVA）, corrected distance visual acuity（CDVA）, refractive errors, mean simulated keratometry readings SimK_（avg）, anterior and posterior corneal asphericity values（Q_（ant） and Q_（post）, respectively） measured with Scheimpflug topography were evaluated retrospectively. RESULTS： There was a significant improvement in UDVA and CDVA, along with a significant decrease in refractive spherical equivalent（SE）, cylinder and SimK_（avg） postoperatively（P〈0.001 for all）. Mean Qant increased from-1.06±0.48 to-0.57±0.58 postoperatively（P〈0.001）. Change in mean Qpost was insignificant（P=0.92）. Postoperative changes in UDVA and CDVA were not correlated with the postoperative changes in SE and cylinder（P〉0.05 for all）; but were correlated with the preoperative SimK_（avg） and Q_（ant） values（P〈0.001 for all）. CONCLUSION： ICRS implantation seems to approximate the anterior corneal asphericity of ＂advanced prolate＂ shape to ＂optimal prolate＂ shape and an ＂ideal Q value＂ of-0.46; which may have a role in improved UDVA and CDVA postoperatively, besides decreased refractive cylinder values.
文摘In order to produce the high quality optical aspheric lens,the shrinkage of lens should be strictly controlled during the injection process.Serials of experiments are done to find the factors that affect the lens shrinkage during the injection molding process.The study is focused on the effect of gate size,packing time and pressure on the shrinkage.The gate size decides the effective packing time.Only when the effective packing time is enough,the shrinkage size will be decreased along with the packing pressure increased.However the packing time is determined by the gate size.But big gate size is not easily to be cut and the cutting difficulty will cause the part quality problems.The experiments show that packing pressure not only determines the part shrinkage size and also affects the part shrinkage uniformity.When the packing pressure is more than a critical one,the effect of packing pressure on the shrinkage size becomes smaller.And the shrinkage uniformity is guaranteed.
基金Fellowship of China National Postdoctoral Program for Innovative Talents(Grant No.BX20200268)Research Project of State Key Laboratory of Mechanical System and Vibration(Grant No.MSV202103)+1 种基金National Natural Science Foundation of China(Grant No.51720105016)Higher Education Discipline Innovation Project(Grant No.B12016).
文摘Precision grinding is a key process for realizing the use of large-aperture aspherical optical elements in laser nuclear fusion devices,large-aperture astronomical telescopes,and high-resolution space cameras.In this study,the arc envelope grinding process of large-aperture aspherical optics is investigated using a CM1500 precision grinding machine with a maximum machinable diameter ofΦ1500 mm.The form error of the aspherical workpiece induced by wheel setting errors is analytically modeled for both parallel and cross grinding.Results show that the form error is more sensitive to the wheel setting error along the feed direction than that along the lateral direction.It is a bilinear function of the feed-direction wheel setting error and the distance to the optical axis.Based on the error function above,a method to determine the wheel setting error is proposed.Subsequently,grinding tests are performed with the wheels aligned accurately.Using a newly proposed partial error compensation method with an appropriate compensation factor,a form error of 3.4μm peak-to-valley(PV)for aΦ400 mm elliptical K9 glass surface is achieved.
基金supported by the Ministry of Economy,Industry and Competitiveness of Spain within the program Ramón y Cajal,RYC-2016-20471Additionally he received an unrestricted grant from Johnson and Johnson Vision for the performance of this research
文摘AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles.METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1 y were included. In all cases, a corneal curvature analysis was performed with IOL-Master(IOLM), iDesign 2(ID2), and Sirius systems(SIR). Differences between instruments for flattest(K1) and steepest(K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity(Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21(P<0.001),-0.12±0.36(P=0.046) and-0.32±0.36 D(P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33(P<0.001),-0.08±0.43(P=0.265) and-0.39±0.38 D(P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance(0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis(26.68o, 33.83o and 18.37o, P≥0.121) and for Q between SIR and ID2(0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provideby the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.
文摘With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i ncreased rapidly in the recent years. The key technologies of fabrication of asp heric plastic lens are the design and manufacturing moulds, selection of proper injection moulding equipment, and optimization of injection moulding parameters etc. In this paper, the effect of injection pressure, moulding temperature, cool ing time and injection speed on the surface profile of the lenses during injecti on and holding process is investigated. Surface quality of plastic lenses is mea sured by Talysurf Texture Measuring System. The experimental results showed that the injection pressure and moulding temperature are important parameters compar ing to cooling time and injection speed. A bit change of injection pressure or m oulding temperature will affect the property of the surface profile. Either incr easing injection pressure or mould temperature can achieve less shrinkage. Other wise, a lower injection pressure will produce more shrinkage, more air traps and a lower mould temperature results greater warp and higher shrinkage. The dynami c process of injection for optical plastic lenses is simulated by 3D Moldflow pl astic Insight software (MPI). The MPI will help us to optimize injection mouldin g parameters.
基金This work was supported by the State Education Commission and the National Natural Science Foundation of China
文摘The shape asymmetry of gaussian models of linear and circular macromolecules has been numerically investigated in terms of asphericity and prolateness parameters. These parameters are found to decrease with increasing length for the macromolecule either confined to a plane or in three dimensions. The effect of dimensionality on these parameters is visible only for low dimensions and is generally weak. As dimensionality goes to infinity, it is found that asphericity and prolateness for both chains and rings approach slowly yet descendingly values of corresponding asphericity and prolateness factors, with the exception of the chain which shows a minimum value of asphericity when the embedding space has a dimensionality of four.
基金the Ministerial Level Foundation (4645103030401)
文摘Design method and procedures of computer-generated hologram （CGH） used for aspheric test are in- troduced in detail. For CGH phase calculation, virtual medium which has zero refractive index at given wavelength is used to model ideal aspheric wavefront. Reflective Fresnel zones located in a ring area concentric to the CGH structure is designed to reduce or eliminate alignment errors. Substrate figure error, pattern distortion, etching and duty cycle variations that influence the reconstructed wavefront are quantitatively analyzed in theory and corresponding error equations are obtained to guide the tolerance distribution during CGH fabricating. A design example is given and the uncertainty of t achieves λ20.
文摘According to the theory of testing aspherical surface by normal aberration compensation method,the designing method of quasi-universal compensator is studied.On the basis of third-order aberration theory,after calculating and optimizing with an optical design program,the structure parameters of a compensator are obtained.This new compensator could be used in Twyman-Green interferometer,and in measurement of a certain range of paraboloid ellipsoid and hyperboloid.The compensation accuracy is more than 0.02 λ .
文摘The original idea and shaping principle of locus shaping method for processing the aspheric optical parts are introduced, and the partial structure of the machine tool designed is described. The method has the advantage of high efficiency and low cost compared to the numerical control method. And it is proven that the method is feasible.
