Effect of low-degree astigmatism on the objective visual quality

AIM:To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System(OQAS).METHODS:This study enrolled 46 participants(aged 23 to 30y,90 eyes)with normal or corrected-to-normal vision.The cylindrical lenses(0,0.5,0.75,1.0,and 1.25 D)were placed at the axial direction(180°,45°,90°,and 135°)in front of the eyes with the best correction to form 16 types of regular low-degree astigmatism.OQAS was used to detect the objective visual quality,recorded as the objective scattering index(OSI),OQAS values at contrasts of 100%,20%,and 9%predictive visual acuity(OV100%,OV20%,and OV9%),modulation transfer function cut-off(MTFcut-off)and Strehl ratio(SR).The mixed effect linear model was used to compare objective visual quality differences between groups and examine associations between astigmatic magnitude and objective visual quality parameters.RESULTS:Apparent negative relationships between the magnitude of low astigmatism and objective visual quality were observed.The increase of OSI per degree of astigmatism at 180°,45°,90°,and 135°axis were 0.38(95%CI:0.35,0.42),0.50(95%CI:0.46,0.53),0.49(95%CI:0.45,0.54)and 0.37(95%CI:0.34,0.41),respectively.The decrease of MTFcut-off per degree of astigmatism at 180°,45°,90°,and 135°axis were-10.30(95%CI:-11.43,-9.16),-12.73(95%CI:-13.62,-11.86),-12.75(95%CI:-13.79,-11.70),and-9.97(95%CI:-10.92,-9.03),respectively.At the same astigmatism degree,OSI at 45°and 90°axis were higher than that at 0°and 135°axis,while MTFcut-off were lower.CONCLUSION:Low astigmatism of only 0.50 D can significantly reduce the objective visual quality.

Evaluation of visual quality of spherical and aspherical intraocular lenses by Optical Quality Analysis System

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.

Reproducibility of optical quality parameters measured at objective and subjective best focuses in a doublepass system

AIMTo evaluate intra-session repeatability and reproducibility of optical quality parameters measured at objective and subjective best focuses in a double-pass system.METHODSThirty Chinese healthy adults (19 to 40 years old) meeting our inclusion criterion were enrolled in the study. After a basic eye examination, two methods of optical quality measurement, based on subjective and objective best focuses were performed using the Optical Quality Analysis System (OQAS) with an artificial pupil diameter of 4.0 mm.RESULTSWith each method, three consecutive measurements of the following parameters: the modulation transfer function cutoff frequency (MTFcutoff), the Strehl2D ratio, the OQAS values (OVs) at contrasts of 100%, 20%, 9% and the objective scatter index (OSI) were performed by an experienced examiner. The repeatability of each method was evaluated by the repeatability limit (RL) and the coefficient of repeatability (COR). Reproducibility of the two methods was evaluated by intra-class correlation coefficient (ICC) and the 95% limits of agreement (Bland and Altman analysis). Thirty subjects, seven females and twenty three males, of whom 15 right eyes and 15 left eyes were selected randomly for recruitment in the study. The RLs (percentage) for the six parameters measured at objective focus and subjective focus ranged from 8.44% to 15.13% and 10.85% to 16.26%, respectively. The CORs for the two measurement methods ranged from 8.27% to 14.83% and 10.63% to 15.93%, respectively. With regard to reproducibility, the ICCs for the six parameters of OQAS ranged from 0.024 to 0.276. The 95% limits of agreement obtained for the six parameters (in comparison of the two methods) ranged from -0.57 to 42.18 (MTFcutoff), -0.01 to 0.23 (Strehl2D ratio), -0.02 to 1.40 (OV100%), -0.10 to 1.75 (OV20%), -0.14 to 1.80 (OV9%) and -1.46 to 0.18 (OSI).CONCLUSIONMeasurements provided by OQAS with either method showed a good repeatability. However, the results obtained from the two different measurement methods showed a poor reproducibility. These findings suggest that it might be best to evaluate patients' optical quality by OQAS using the best focus as chosen automatically by the instrument.

Analysis of the optical quality by determining the modulation transfer function for anterior corneal surface in myopes

AIM: To describe the characteristics of modulation transfer function (MTF) of anterior corneal surface, and obtain the the normal reference range of MTF at different spatial frequencies and optical zones of the anterior corneal surface in myopes. METHODS: Four hundred eyes from 200 patients were examined under SIRIUS corneal topography system. Phoenis analysis software was applied to simulate the MTF curves of anterior corneal surface at vertical and horizontal meridians at the 3, 4, 5, 6, 7mm optical zones of cornea. The MTF values at spatial frequencies of 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 cycles/degree (c/d) were selected. RESULTS: The MTF curve of anterior corneal surface decreased rapidly from low to intermediate frequency (0-15cpd) at various optical zones of cornea, the value decreased to 0 slowly at higher frequency (>15cpd). With the increase of the optical zones of cornea, MTF curve decreased gradually. 3) In the range of 3 mm- 6 mm optical zones of the cornea, the MTF values measured at horizontal meridian were greater than the corresponding values at horizontal meridian of each spatial frequency, the difference was statistically significant (P<0.05). At 7 mm optical zones of cornea, the MTF values measured at horizontal meridian were less than the corresponding values at vertical meridian at 10-60 spatial frequencies (cpd), and the difference was statistically significant in 25, 30, 35, 40, 45, 50 cpd(P<0.05). CONCLUSION: MTF can be used to describe the imaging quality of optical systems at anterior corneal surface objectively in detail.

Optical quality of toric intraocular lens implantation in cataract surgery

AIM: To analyze the optical quality after implantation of toric intraocular lens with optical quality analysis system.METHODS: Fifty-two eyes of forty-four patients with regular corneal astigmatism of at least 1.00 D underwent implantation of Acry Sof toric intraocular lens, including T3 group 19 eyes, T4 group 18 eyes, T5 group 10 eyes,T6 group 5 eyes. Main outcomes evaluated at 3mo of follow-up, included uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), residual refractive cylinder and intraocular lens(IOL) axis rotation.Objective optical quality were measured using optical quality analysis system(OQAS Ⅱ, Visiometrics, Spain),included the cutoff frequency of modulation transfer function(MTFcutoff), objective scattering index(OSI),Strehl ratio, optical quality analysis system value(OV)100%, OV 20% and OV 9% [the optical quality analysis system(OQAS) values at contrasts of 100%, 20%, and 9%].RESULTS: At 3mo postoperative, the mean UDVA and CDVA was 0.18 ±0.11 and 0.07 ±0.08 log MAR; the mean residual refractive cylinder was 0.50 ±0.29 D; the mean toric IOL axis rotation was 3.62 ±1.76 degrees, the mean MTFcutoff, OSI, Strehl ratio, OV 100%, OV 20% and OV9% were 22.862 ±5.584, 1.80 ±0.84, 0.155 ±0.038, 0.76 ±0.18,0.77±0.19 and 0.78±0.21. The values of UDVA, CDVA, IOL axis rotation, MTFcutoff, OSI, Strehl ratio, OV100%,OV20% and OV9% depending on the power of the cylinder of the implantation were not significantly different(P 】0.05), except the residual refractive cylinder(P 【0.05).CONCLUSION: The optical quality analysis system was useful for characterizing the optical quality of Acry Sof toric IOL implantation. Implantation of an Acry Sof toric IOL is an effective and safe method to correct corneal astigmatism during cataract surgery.

Comparison of postoperative optical quality according to the degree of decentering of V4c implantable collamer lens

AIM：To evaluate the clinical outcomes of V4 c implantable collamer lens（Hole ICL） implantation with regard to the optical quality assessed according to different degrees of decentering.METHODS：This included 49 eyes that received conventional ICL and 94 eyes that received Hole ICL.The eyes that received Hole ICL were divided into three groups according to the degree of decentering：group 1,central hole within 1 hole diameter（HD） from the pupil center;group 2,central hole within 1 HD to 2 HD;and group 3,central hole within 2 HD to 3 HD.Visual acuity（VA）,intraocular pressure（IOP）,and spherical equivalent（SE） values were assessed at 1wk,1 and 3mo after surgery.The ocular modulation transfer function,Strehl ratio,objective scattering index,and higher order aberrations（HOAs） were measured for 4-mm pupils at 3mo after surgery.RESULTS：There were no significant differences in VA,IOP,and SE among the conventional and Hole ICL groups.With regard to HOAs,values for coma and spherical aberrations showed no differences.The total HOA and trefoil values were significantly higher in group 2 than in group 1（P=0.02,0.03,respectively）.There were no significant differences among groups with regard to other optical quality parameter at 3mo after surgery.CONCLUSION：Our results suggest that Hole ICL implantation provides satisfactory visual quality that is equivalent to that provided by conventional ICL,regardless of the presence of central hole and degree of decentering.

Objective optical quality and visual outcomes after the PresbyMAX monocular ablation profile

AIM:To assess objective visual quality after presbyopia correction using the Presby MAX monocular mode.METHODS:This prospective,nonrandomized study included 28 eyes from 18 patients(mean age 50.4±5.6 y)who underwent presbyopia correction with the Presby MAX monocular mode.Monocular and binocular visual acuities were evaluated preoperatively,1 d,1 wk,1,3 mo,and 1 y after surgery.Optical quality was analyzed by HartmannShack wavefront aberration supported cornea ablation.Modulation transfer function(MTF)cutoff frequency,Strehl ratio,and objective scattering index(OSI)were analyzed using an optical quality analysis system.RESULTS:One year after surgery,100%and 94.4%of patients achieved binocular uncorrected distance and near visual acuity of 20/25,respectively.At the last visit Spherical aberration and total higher aberration were higher than the corresponding preoperative levels(P<0.001);however,no significant difference was found in MTF,OSI,or Strehl ratio.Transient decreases in OSI and MTF mainly occurred in the nondominant eyes.There was no significant difference in optical quality between the dominant and nondominant eyes,except for spherical aberration and horizontal coma(P<0.05).CONCLUSION:The Presby MAX monocular mode is safe and effective for presbyopia correction.It has little effect on optical quality,though short-term degraded optical quality occurred mainly in the bi-aspheric ablated eyes.

Refractive outcomes and optical quality of PRESBYOND laser-blended vision for presbyopia correction

AIM: To investigate the one-year refractive outcomes and optical quality following PRESBYOND laser-blended vision(LBV).METHODS: This retrospective study included 20 patients who underwent PRESBYOND treatment between Jan 2019 and Aug 2020. The patients were asked to attend a followup outpatient visit one year after surgery. Distance and near visual acuity as well as subjective refraction were examined. Optical quality was assessed using wavefront-supported custom ablation. A questionnaire evaluating optical quality and satisfaction was completed at the last visit.RESULTS: The average patient age was 48.1±7.4 y(range, 41 to 58 y). The mean preoperative spherical equivalent was-7.59±2.39D. At the one-year follow-up, two eyes(both dominant eyes) lost one line of corrected distance visual acuity(CDVA), while the remaining eyes(38/40) maintained or gained lines of CDVA. The average binocular uncorrected distance visual acuity improved from 0.15±0.03 to 0.90±0.26(decimal vision;P<0.001). The average binocular uncorrected near visual acuity increased from 0.34±0.28 to 0.97±0.07(P<0.001). The spherical aberration was 0.04±0.06 μm in the nondominant eye and 0.09±0.09 μm in the dominant eye(P=0.02). All patients were satisfied with or accepted the outcomes of the surgery. The primary complaints were related to disturbances in night vision and relatively inferior near vision.CONCLUSION: Over the one-year observation period, PRESBYOND is a safe and effective option for presbyopia correction. The optical quality and near vision deserve further investigation.

Comparison of optical quality after implantable collamer lens implantation and wavefront-guided laser in situ keratomileusis

AIM： To compare the optical quality after implantation of implantable collamer lens（ICL） and wavefront-guided laser in situ keratomileusis（WG-LASIK）.METHODS： The study included 40 eyes of 22 patients with myopia who accepted ICL implantation and 40 eyes of 20 patients with myopia who received WG-LASIK. Before surgery and three months after surgery, the objective scattering index（OSI）, the values of modulation transfer function（MTF） cutoff frequency, Strehl ratio, and the Optical Quality Analysis System（OQAS） values（OVs） were accessed. The higher order aberrations（HOAs） data including coma, trefoil, spherical, 2^（nd） astigmatism and tetrafoil were also obtained. For patients with pupil size 〈6 mm, HOAs data were analyzed for 4 mm-pupil diameter. For patients with pupil size ≥6 mm, HOAs data were calculated for 6 mm-pupil diameter. Visual acuity, refraction, pupil size and intraocular pressures were also recorded.RESULTS： In both ICL and WG-LASIK group, significant improvements in visual acuities were found postoperatively, with a significant reduction in spherical equivalent（P〈 0.001）. After the ICL implantation, the OSI decreasedslightly from 2.34±1.92 to 2.24±1.18 with no statistical significance（P=0.62）. While in WG-LASIK group, the OSI significantly increased from 0.68±0.43 preoperatively to 0.91±0.53 postoperatively（Wilcoxon signed ranks test, P=0.000）. None of the mean MTF cutoff frequency, Strehl ratio, OVs showed statistically significant changes in both ICL and WG-LASIK groups. In the ICL group, there were no statistical differences in the total HOAs for either 4 mmpupil or 6 mm-pupil. In the WG-LASIK group, the HOA parameters increased significantly at 4 mm-pupil. The total ocular HOAs, coma, spherical and 2^（nd） astigmatism were 0.12±0.06, 0.06±0.03, 0.00±0.03, 0.02±0.01, respectively. After the operation, these values were increased into 0.16±0.07, 0.08±0.05,-0.04±0.04, 0.03±0.01 respectively（Wilcoxon signed ranks test, all P〈0.05）. At 6 mm-pupil, the induction of total HOAs was not statistically significant in the WG-LASIK group. CONCLUSION： ICL implantation has a less disturbance to optical quality than WG-LASIK. The OQAS is a valuable complementary measurement to the wavefront aberrometers in evaluating the optical quality.

Repeatability of in-vitro optical quality measurements of intraocular lenses with a deflectometry technique effect of the toricity

AIM： To evaluate the repeatability of an optical device for measuring the Zernike coefficients of toric intraocular lenses（IOLs） and assess whether its toricity has any impact in its repeatability. METHODS： An experienced technician used the NIMO TR1504 to measure the Zernike coefficients 30 times for an aperture of 4.50 mm for all lenses included. The IOLs included were divided into two group： toric and nontoric ones. The cylindrical powers of the toric lenses included in the present study were 1.00, 1.50, 2.25, 3.00 and 3.75 D. Finally, the repeatability of the NIMO TR1504 was described in terms of within subject standard deviation（Sw） and repeatability limit. RESULTS： The Sw was smaller than 0.011 μm for both lens groups and all Zernike coefficients, and the difference between both groups was smaller than 0.004 μm for all Zernike coefficients. Regarding the repeatability limit, this value was smaller than 0.025 μm for the toric lens group, and smaller than 0.031 μm for the non-toric lens one for all Zernike coefficients. Furthermore, the maximum difference between both lens groups was 0.010 μm. CONCLUSION： The repeatability of the NIMO TR1504 to measure the optical quality is high and independent of the lens toricity. These results reflect that this system is robust and could be used to measure the in-vitro optical quality of either toric or non-toric IOLs.

QoS aware routing and wavelength allocation in optical burst switching networks using differential evolution optimization

The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article presents a QoS aware Routing and Wavelength Allocation （RWA） technique for burst switching in OBS networks. The RWA problem is modeled as a bi-objective Integer Linear Programming （ILP） problem, where objective functions are based on minimizing the number of wavelengths used and the number of hops traversed to fulfill the burst transmission requests for a given set of node pairs. The ILP model is solved using a novel approach based on a Differential Evolution （DE） algorithm. Analytical results show that the DE algorithm provides a better performance compared to shortest path routing, which is a widely accepted routing strategy for OBS networks.

Effect of Y substitution on the microstructure,magneto-optical,and thermal properties of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)transparent ceramics

Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y_(2)O_(3) was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.

In vivo optical quality of posterior-chamber phakic implantable collamer lenses with a central port

Background: The aim of this review is to summarize the optical quality results in patients following theimplantation of the V4c implantable collamer lens with a central port (ICL, STAAR Surgical Inc.).Main text: A literature search in several databases was carried out to identify those publications, both prospective,retrospective and/or comparative with other refractive surgery procedures, reporting optical outcomes of patientswho were implanted with the V4c ICL model. A total of 17 clinical studies published between 2012 and 2021 wereincluded in this review. A detailed analysis of the available data was performed including number of eyes, follow-upand preoperative spherical equivalent. Specifically, the review focused on several optical parameters includinghigher-order aberrations (HOAs), modulation transfer function (MTF) cut-off frequency and Strehl ratio. This reviewencompassed a total of 817 eyes measured using different optical devices based on Hartmann-Shack, retinal imagequality measurement and ray-tracing technologies at different follow-ups.Conclusions: The outcomes found in this review lead us to conclude that the ICL V4c model provides good opticalquality, by means of different metrics, when implanted.

In vivo optical quality of posterior-chamber phakic implantable collamer lenses with a central port

Background:The aim of this review is to summarize the optical quality results in patients following the implantation of the V4c implantable collamer lens with a central port(ICL,STAAR Surgical Inc.).Main text:A literature search in several databases was carried out to identify those publications,both prospective,retrospective and/or comparative with other refractive surgery procedures,reporting optical outcomes of patients who were implanted with the V4c ICL model.A total of 17 clinical studies published between 2012 and 2021 were included in this review.A detailed analysis of the available data was performed including number of eyes,follow-up and preoperative spherical equivalent.Specifically,the review focused on several optical parameters including higher-order aberrations(HOAs),modulation transfer function(MTF)cut-off frequency and Strehl ratio.This review encompassed a total of 817 eyes measured using different optical devices based on Hartmann-Shack,retinal image quality measurement and ray-tracing technologies at different follow-ups.Conclusions:The outcomes found in this review lead us to conclude that the ICL V4c model provides good optical quality,by means of different metrics,when implanted.

Non-cycloplegic spherical equivalent refraction in adults:comparison of the double-pass system,retinoscopy,subjective refraction and a table-mounted autorefractor

AIM:To evaluate the accuracy of spherical equivalent(SE) estimates of a double-pass system and to compare it with retinoscopy,subjective refraction and a table mounted autorefractor.METHODS:Non-cycloplegic refraction was performed on 125 eyes of 65 healthy adults(age 23.5±3.0 years) from October 2010 to January 2011 using retinoscopy,subjective refraction,autorefraction(Auto kerato refractometer TOPCON KR-8100,Japan) and a double pass system(Optical Quality Analysis System,OQAS,Visiometrics S.L.,Spain).Nine consecutive measurements with the double-pass system were performed on a subgroup of 22 eyes to assess repeatability.To evaluate the trueness of the OQAS instrument,the SE laboratory bias between the double pass system and the other techniques was calculated.RESULTS:The SE mean coefficient of repeatability obtained was 0.22D.Significant correlations could be established between the OQAS and the SE obtained with retinoscopy(r=0.956,P【0.001),subjective refraction(r=0.955,P【0.001) and autorefraction(r=0.957,P【0.001).The differences in SE between the double-pass system and the other techniques were significant(P【0.001),but lacked clinical relevance except for retinoscopy;Retinoscopy gave more hyperopic values than the double-pass system-0.51±0.50D as well as the subjective refraction-0.23±0.50D;More myopic values were achieved by means of autorefraction 0.24±0.49D. CONCLUSION:The double-pass system provides accurate and reliable estimates of the SE that can be used for clinical studies.This technique can determine the correct focus position to assess the ocular optical quality.However,it has a relatively small measuring range in comparison with autorefractors(-8.00 to +5.00D),and requires prior information on the refractive state of the patient.

Effect of refractive correction on ocular optical quality measurement using double-pass system

Background Optical Quality Analysis System II （OQAS, Visiometrics, Terrassa, Spain） that uses double-pass （DP） technique is the only commercially available device that allows objective measurement of ocular retinal image quality. This study aimed to evaluate the impact of spectacle lenses on the ocular optical quality parameters and the validity of the optometer within OQAS. Methods Seventy eyes of healthy volunteers were enrolled. Optical quality measurements were performed using OQAS with an artificial pupil diameter of 4.0 mm. Three consecutive measurements were obtained from spectacle correction corresponding to subjective refraction and from the OQAS built-in optometer separately. The modulation transfer function cutoff frequency, the Strehl ratio, the width of the point spread function （PSF） at 10% of its maximal height （PSF10）, and the width of the PSF at 50% of its maximal height （PSF50） were analyzed. Results There was no significant difference in any of the parameters between the spectacle correction and the optometer correction （all P 〉0.05, paired t-test）. A good agreement was found between both the methods and a good intraobserver repeatability in both the correction methods. Difference in best focus between two methods was the only parameter associated significantly with optical quality parameter differences. Best focus difference, built-in optometer correction with or without external cylindrical lens, and age were associated significantly with PSF10 difference. No linear correlation between refractive status and optical quality measurement difference was observed. A hyperopic bias （best focus difference of （0.50±0.44） D） and a relatively better optical quality using spectacle correction in high myopia group were found. Conclusions OQAS based on DP system is a clinically reliable instrument. In patients with high myopia, measurements using built-in optometer correction should be considered and interpreted with caution.

A review on magneto-optical ceramics for Faraday isolators

As a promising magneto-optical(MO)material applied in Faraday isolators,magneto-optical ceramics possess excellent comprehensive properties and have attracted much attention these years.Herein,we review the fabrication and properties of magneto-optical ceramics including garnet,sesquioxide,and A_(2)B_(2)O_(7) ceramics.Some of the ceramics have been proved to possess applicable performance,while further studies are still needed for most of the magneto-optical ceramics.Aiming at the application for isolators,the research status,existing problems,and development trends of magneto-optical ceramics are shown and discussed in this review.

The relationship between patient satisfaction and visual and optical outcome after bilateral implantation of an extended depth of focus multifocal intraocular lens

Purpose:To evaluate patient satisfaction after implantation of the Tecnis Symfony multifocal intraocular lens(MIOL).Methods:120 eyes of 60 subjects with senile cataract were bilaterally implanted with the Tecnis Symfony IOL.Follow-up examination was performed 6 months postoperatively.Main outcome measures included uncorrected and corrected distance and near visual acuity,manifest refraction,and visual quality metrics.According to their subjective symptoms patient were divided in two groups:satisfied and unsatisfied.Results:Uncorrected intermediate(0.15±0.11 vs 0.18±0.01,P=0.04)and near(0.26±0.12 vs 0.31±0.11,P=0.04)(UIVA,UNVA)log MAR visual acuity was significantly better,cylindrical error less(0.31±0.36 vs 0.67±0.29,P=0.05),axial length(AL)smaller(23.68±1.3 vs 24.22±1.6,P=0.05),Strehl ratio higher(0.08±0.08 vs 0.05±0.04,P=0.03)and mesopic pupil larger(4.3±1.1 vs 3.7±1.05,P=0.01)among satisfied patients.Residual cylinder,Strehl ratio,halos,mesopic pupil diameter and UNVA were significant predictors of patient satisfaction.Uncorrected distance visual acuity,higher order Strehl ratio and pupil diameter were significant predictors of halos.Near visual acuity significantly correlated(P=0.018,R=0.22)with axial length.Conclusions:Uncorrected cylindrical error,poor reading quality,larger pupil and halos seem to be the most disturbing factors for patients implanted with the Tecnis Symfony IOL.