Effectivity and safety of trifocal intraocular lenses and capsular tension rings implantation for cataract patients with axial high myopia

●AIM:To assess effectivity and safety of trifocal intraocular lenses(IOLs)and capsular tension rings in treating cataract patients with axial high myopia.●METHODS:A prospective nonrandomized controlled clinical trial was conducted.Totally 98 eyes(74 patients)who underwent femtosecond laser-assisted cataract surgery(FLACS)with trifocal IOLs were enrolled in the study and followed up for 2y after surgery:46 eyes(33 patients)with capsular tension ring implantation in the long axial lengths(AL)group(26<AL<29 mm)and 52 eyes(41 patients)in the normal AL group(22<AL<24.5 mm).Postoperative outcomes about effectivity and safety,including the subjective and objective visual quality,and postoperative complications were assessed.●RESULTS:Uncorrected distance visual acuity at 5 m and uncorrected intermediate visual acuity at 60 and 80 cm in the long AL group were significantly worse than those in the normal AL group at 3mo postoperatively(P<0.05).The differences in reading speed,spectacle independence and potential visual complaints between the two groups were not statistically significant(P>0.05).The dysfunctional lens index and total modulation transfer function(MTF)average height were similar between the two groups.The postoperative internal coma aberrations in the axial high myopia eyes were significantly higher than that in the normal AL group(P<0.05).The total satisfaction score in the long AL group(91.32±2.76)was slightly higher than that in the normal AL group(90.36±3.47),but there was no difference(P=0.136).A statistically negative correlation was found between corrected distance visual acuity(CDVA)and dysfunctional lens index(r=-0.382,P=0.009),and between CDVA and the total MTF average height(r=-0.374,P=0.01).But there was no significant correlation between CDVA and total satisfaction score(r=0.059,P=0.696).Postoperative complications mainly presented as posterior capsular opacity(PCO),retinal detachment and cystoid macular edema.There was no difference in the incidence of fundus disease(6.5%vs 3.8%,P=0.663)or PCO(17.4%vs 7.7%,P=0.217)between the two groups at two years.●CONCLUSION:The utilization of trifocal IOL and capsular tension ring implantation is beneficial for cataract patients with axial high myopia undergoing FLACS.This approach not only ensures excellent subjective feelings and objective visual quality,but also does not increase the incidence of postoperative complications.

Changes in visual performance after implantation of different intraocular lenses

AIM:To evaluate the trending visual performance of different intraocular lenses(IOLs)over time after implantation.METHODS:Ninety-one patients received cataract surgery with implantations of monofocal(Mon)IOLs,segmental refractive(SegRef)IOLs,diffractive(Dif)IOLs,and extendeddepth-of-focus(EDoF)IOLs were included.The aberrations and optical quality collected with iTrace and OQAS within postoperative 6mo were followed and compared.RESULTS:Most of the visual parameters improved over the postoperative 6mo.The postoperative visual acuity(POVA)of the Mon IOL,SegRef IOL,and EDoF IOL groups achieved relative stability in earlier states compared with the Dif IOL group.Nevertheless,the overall visual performance of the 3 IOLs continued to upturn in small extents within the postoperative 6mo.The optical quality initially improved in the EDoF IOL group,then in the Mon IOL,SegRef IOL,and Dif IOL groups.POVA and objective visual performance of the Mon IOL and EDoF IOL groups,as well as POVA and visual quality of the Dif IOL group,improved in the postoperative 1mo and stabilized.Within the postoperative 6mo,gradual improvements were observed in the visual acuity and objective visual performance of the SegRef IOL group,as well as in the postoperative optical quality of the Dif IOL group.CONCLUSION:The visual performance is different among eyes implanted with different IOLs.The findings of the current study provide a potential reference for ophthalmologists to choose suitable IOLs for cataract patients in a personalized solution.

Sutured scleral fixation of existing subluxated/dislocated acrylic one-piece intraocular lenses

AIM:To evaluate the visual and refractive outcomes in cases after sutured scleral fixation of existing subluxated or dislocated acrylic one-piece intraocular lenses(IOLs).METHODS:This study retrospectively enrolled a consecutive series of patients who underwent a surgery of sutured existing subluxated or dislocated IOLs from October 2018 to June 2020.All patients underwent comprehensive preoperative and postoperative ophthalmologic examination,and data were collected including age,sex,surgical indications,best-corrected visual acuity,refractive error,intraocular pressure.Presence of intraoperative and postoperative surgical complications was documented.RESULTS:A total of 20 consecutive cases were enrolled for analysis with mean final follow-up period 9.8±5.3mo.Visual acuity improved from a mean of 0.35(0.46±0.32 logMAR)preoperatively to 0.61(0.21±0.18 logMAR)at the 3-month follow-up(P=0.002).The mean amount of preoperative keratometric astigmatism and total postoperative refractive astigmatism was-1.24±0.80 diopters(D)and-1.42±0.97 D,respectively.There was no statistically significant difference between preoperative and postoperative astigmatism(P=0.156).The mean IOL-induced astigmatism was-0.23±0.53 D.The mean spherical equivalent at the 3-month follow-up was-0.1±0.94 D.No major complications were noted during the follow-up period.CONCLUSION:Surgical techniques using sutured scleral fixation of existing subluxated or dislocated acrylic one-piece IOLs result in favorable visual and refractive outcomes without major complications.

Efficacy of custom-made soft keratoconus lenses on corneal aberrations and photic phenomena in patients with keratoconus:a corneal topography imaging based study

AIM:To evaluate the efficacy of custom-made soft keratoconus(KC)lenses on corneal aberrations and photic phenomena in two different optical zones in patients with KC.METHODS:Sixty eyes of 42 patients with KC were examined at baseline and after fitting HydroCone(Toris K)soft silicone hydrogel lenses.Best spectacle-corrected visual acuity(BSCVA)and contact lens-corrected visual acuity(CLCVA)were recorded.Lower-and higher-order corneal aberrations(LOAs and HOAs)were measured with and without Toris K lenses and compared in central 4.5 mm and 7 mm zones.Mesopic pupil diameter and subjective photic phenomena were also assessed.RESULTS:Mean CLCVA was significantly improved compared to BSCVA(P<0.0001).Corneal curvature and refractive measurements were found to be significantly reduced by the use of Toris K lenses,except for posterior corneal curvature values.In the 4.5 mm central optical zone,all wavefront aberrations decreased significantly after lens fitting(P<0.0001).In contrast,in the 7 mm(peripheral)optical zone,values for HOAs,spherical and residual aberrations,and optical path differences were increased,while LOAs,trefoil,and quadrifoil coefficients were decreased.The rate of photic phenomena was significantly higher in participants with a pupil size>6.00 mm(85.7%).CONCLUSION:Toris K lenses provide good visual results and a significant reduction in central corneal aberrations in patients with KC but could cause an increase in peripheral aberrations.This practical and nonsurgical approach appears to be an effective method for the visual management of KC.

A new software for automated counting of glistenings in intraocular lenses in vivo

AIM:To assess the performance of a bespoke software for automated counting of intraocular lens(IOL)glistenings in slit-lamp images.METHODS:IOL glistenings from slit-lamp-derived digital images were counted manually and automatically by the bespoke software.The images of one randomly selected eye from each of 34 participants were used as a training set to determine the threshold setting that gave the best agreement between manual and automatic grading.A second set of 63 images,selected using randomised stratified sampling from 290 images,were used for software validation.The images were obtained using a previously described protocol.Software-derived automated glistenings counts were compared to manual counts produced by three ophthalmologists.RESULTS:A threshold value of 140 was determined that minimised the total deviation in the number of glistenings for the 34 images in the training set.Using this threshold value,only slight agreement was found between automated software counts and manual expert counts for the validating set of 63 images(κ=0.104,95%CI,0.040-0.168).Ten images(15.9%)had glistenings counts that agreed between the software and manual counting.There were 49 images(77.8%)where the software overestimated the number of glistenings.CONCLUSION:The low levels of agreement show between an initial release of software used to automatically count glistenings in in vivo slit-lamp images and manual counting indicates that this is a non-trivial application.Iterative improvement involving a dialogue between software developers and experienced ophthalmologists is required to optimise agreement.The results suggest that validation of software is necessary for studies involving semi-automatic evaluation of glistenings.

Effectiveness of toric soft contact lenses for vision correction in patients with different degrees of astigmatism: a real-world study

AIM:To assess the visual correction of patients with different degrees of astigmatism with toric soft contact lenses(TSC).METHODS:It was a real-world study with prospective and single-arm design.A total of 384 patients with astigmatism who came for TSC fitting and alignment from November 2022 to January 2023 were included.According to the difference in astigmatism,patients were divided into groups A(cylinder degree:-0.75 to-0.50 D),B(cylinder degree:-1.75 to-1.00 D)and C(cylinder degree≤-2.00 D),and followed up on the day of wear,1wk,1 and 3mo,mainly to observe visual acuity,refraction,lens fit,visual quality and comfort at 1wk after wear.The visual acuity success rate and the overall success rate of the fitting were evaluation indicators(taking into account the four dimensions of visual acuity,fitting,quality of vision and comfort).The visual acuity success rate was calculated by taking“corrected visual acuity with contact lenses is no less than 1 line or better than best spectacle-corrected visual acuity”(i.e.corrected visual acuity with contact lenses is 1 line below,equal to,one line above or more than best spectaclecorrected visual acuity)as the criterion for visual success,and the the overall success rate of the fitting was calculated by using the comprehensive indicators(visual acuity,fit,visual quality,comfort)to meet certain conditions as the judgment criteria for successful fitting.RESULTS:After 1wk of wearing TSC,the visual acuity success rates of patients were 100%(207/207),98.58%(139/141)and 97.22%(35/36)in the three groups,respectively,with residual cylinder closed to 0.The acceptability of the lens fitting was over 95%;the incidence of adverse visual symptoms was within 10%and the comfort acceptability was over 97%.The overall success rate of fitting for patients with high,medium and low astigmatism was 93.72%(194/207),90.78%(128/141)and 88.89%(32/36),respectively.CONCLUSION:TSC(model:G&G POP·CT)are effective in correcting astigmatism in patients with different degrees of astigmatism.

Rotational stability of plate haptic toric intraocular lenses after combined 25-gauge vitrectomy and cataract surgery

AIM:To evaluate the postoperative intraocular lens(IOL)rotational stability and residual refractive astigmatism following combined 25-gauge vitrectomy and cataract surgery with implantation of a plate haptic toric IOL.METHODS:In this retrospective case series,32 eyes of 32 patients underwent a combined 25-gauge vitrectomy and phacoemulsification for vitreoretinal diseases and cataract with regular corneal astigmatism of at least 1 diopter(D).A plate haptic toric IOL(AT Torbi 709M,Carl Zeiss Meditec AG)was implanted in all eyes.The outcome measures were rotational stability and refractive astigmatism up to 6mo postoperatively as well as the best corrected visual acuity(BCVA).RESULTS:Preoperative refractive astigmatism was 2.14±1.17 D,which was significantly reduced to 0.77±0.37 D six to eight weeks postoperatively and remained stable throughout the observation period(0.67±0.44 D at three months and 0.75±0.25 D at six months;for all groups:P<0.0001 compared to baseline).BCVA improved significantly from 0.36±0.33 logMAR preoperatively to 0.10±0.15 logMAR following surgery(P=0.02).Mean IOL axis deviation from the target axis was 3.4°±2.9°after six to eight weeks and significantly decreased over time(2.4°±2.6°six months after surgery;P=0.04).In one patient IOL,re-alignment was performed.CONCLUSION:Corneal astigmatism is significantly reduced following combined 25-gauge vitrectomy and cataract surgery.The plate haptic toric IOL position and axis remain stable during the observation period of six months.

Flapless one-knot suture:a novel surgical technique for transscleral fixation of C-loop intraocular lenses

AIM:To describe a novel suture approach for transscleral fixation of C-loop intraocular lenses(IOL)and to compare the surgical outcomes with the four-haptics posterior chamber(PC)-IOL technique.METHODS:We retrospectively analyzed 16 eyes of 16 patients who underwent transscleral fixation of C-loop PCIOLs using a flapless one-knot suture technique,which were followed up for longer than 17mo.In this technique,the capsulorless IOL was suspended using a single suture for transscleral fixation of four feet.Then we compared its surgical outcomes and complications with the four-haptics PC-IOLs using the Student's t test and Chi-square test.RESULTS:Sixteen patients of 16 eyes with a mean age of 58.3±10.1y(42-76y)who received transscleral C-loop IOL implantation due to trauma,vitrectomy,or cataract surgery with inadequate capsule support showed improved visual acuity.The difference was not significant between two IOLs except the surgery time(P>0.05).The mean operation times of C-loop IOL surgery was 24.1±1.83min and 31.3±4.47min of the four-haptics PC-IOL method(P<0.0001).In the C-loop IOLs group,there was statistical difference between the preoperative and the postoperative UCVA(log MAR,1.20±0.50 vs 0.57±0.32,P=0.0003).There was no statistical difference between the preoperative and the postoperative BCVA(log MAR,0.66±0.46 vs 0.40±0.23,P=0.056).However,there was no statistically significant difference in postoperative UCVA and BCVA between the two IOLs(P>0.05).We did not detect any optic capture,IOL decentration or dislocation,suture exposed,or cystoid macular edema in patients underwent C-loop IOLs surgery.CONCLUSION:The novel flapless one-knot suture technique for transscleral fixation of C-loop IOL is a simple,reliable,and stable technique.

Relativistic Supernova Blast Waves Exhibit Properties of Gravitational Lenses and the Hubble Constant

Simulations based on Supernova (SN) observations predict several galactic SN explosions (SNe) can occur every century. Unlike SNes within the Interstellar Medium (ISM) where ambient gas generally absorbs blast waves within a million years, SNes occurring in a rarified environment outside of the ISM generate blast waves which remain in a relativistic free expansion phase for more extended periods. The SN blast wave forms an expanding spherical shell and when multiple blast waves intersect, the overlapping region naturally takes the form of a ring, an arc, or an Einstein Cross structure. The analysis shows the relativistic plasma establishes a medium with permeability which drives the index of refraction greater than 1. As a result, when a shock discontinuity forms in the overlapping region, light is reflected from the host galaxy which exposes the intersecting blast wave regions. The expanding shells are shown to induce an achromatic redshift to the reflected light consistent with those measured for gravitational lenses. Further, it is shown that a Hubble equation for a blast wave around the Milky Way Galaxy can be parameterized to approximate measured redshifts over a wide range of distances.

Considerations in the management of single-piece intraocular lenses outside the capsular bag

AIM: To investigate the outcomes of off label singlepiece acrylic intraocular lenses(SPA-IOL) ciliary sulcus placement compared to three-piece IOL(3P-IOL). METHODS: The charts of eight consecutive eyes of patients who received sulcus-placed SPA-IOLs between 2006 and 2009 were reviewed. None of the patients underwent IOL exchange. Charts of six age-matched patients who received sulcus placed 3P-IOLs were reviewed as a control group. RESULTS: Mean follow up was 16 mo for SPA-IOL and 23 mo for 3P-IOL. Five of 8 patients in the SPA-IOL group required chronic use of IOP lowering medications at final follow up. Of these, one patient needed glaucoma implant surgery for uncontrolled IOP. One patient in the 3P-IOL group used chronic aqueous suppression pre- and postoperatively. Four of eight eyes with SPAIOL were treated with chronic topical steroids and or non-steroidal anti-inflammatory drugs for cystoid macu-la edema, chronic uveitis, pigment dispersion syndrome or a combination of the above, compared to none in the control group. Mean best-corrected visual acuity was 20/35 in the SPA-IOL group and 20/47 in the 3PIOL group.CONCLUSION: Sulcus placed SPA-IOLs are associated with increased ocular morbidity. In select cases good visual acuity may be achieved. Due to postoperative rotation of sulcus placed toric SPA-IOLs stable astigmatism correction cannot be achieved. Alternative intraocular lenses should be considered when in-the-bag placement of SPA-IOL is not possible.

Zoned Zircon from Eclogite Lenses in Marbles from the Dabie-Sulu UHP Terrane,China: A Clear Record of Ultra-deep Subduction and Fast Exhumation

Eclogite lenses in marbles from the Dabie-Sulu ultrahigh-pressure （UHP） terrane are deeply subducted meta-sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphism during subduction, and later retrograde metamorphism during exhumation. Inherited （detrital） and metamorphic zircons were distinguished on the basis of transmitted light microscopy, cathodoluminescence （CL） imaging, trace element contents and mineral inclusions. The distribution of mineral inclusions combined with CL imaging of the metamorphic zircon make it possible to relate zircon zones （domains） to different metamorphic stages. Domain 1 consists of rounded, oblong and spindly cores with dark-luminescent images, and contains quartz eclogite facies mineral inclusion assemblages, indicating formation under high-pressure （HP） metamorphic conditions of T = 571-668℃ and P =1.7-2.02 GPa. Domain 2 always surrounds domain 1 or occurs as rounded and spindly cores with white-luminescent images. It contains coesite eclogite facies mineral inclusion assemblages, indicating formation under UHP metamorphic conditions of T = 782-849℃ and P 〉 5.5 GPa. Domain 3, with gray-luminescent images, always surrounds domain 2 and occurs as the outermost zircon rim. It is characterized by low-pressure mineral inclusion assemblages, which are related to regional amphibolite facies retrograde metamorphism of T = 600- 710℃ and P = 0.7-1.2 GPa. The three metamorphic zircon domains have distinct ages; sample H1 from the Dabie terrane yielded SHRIMP ages of 245 ± 4 Ma for domain 1, 235 ± 3 Ma for domain 2 and 215± 6 Ma for domain 3, whereas sample H2 from the Sulu terrane yielded similar ages of 244 ± 4 Ma, 233 ± 4 Ma and 214 ± 5 Ma for Domains 1, 2 and 3, respectively. The mean ages of these zones suggest that subduction to UHP depths took place over 10-11 Ma and exhumation of the rocks occurred over a period of 19-20 Ma. Thus, subduction from - 55 km to 〉 160 km deep mantle depth took place at rates of approximately 9.5-10.5 km/Ma and exhumation from depths 〉160 km to the base of the crust at -30 km occurred at approximately 6.5 km/Ma. We propose a model for these rocks involving deep subduction of continental margin lithosphere followed by ultrafast exhumation driven by buoyancy forces after break-off of the UHP slab deep within the mantle.

Electrostatic-lenses position-sensitive TOF MCP detector for beam diagnostics and new scheme for mass measurements at HIAF

A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci,and position measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.

Visual performance after implantation of two types of phakic foldable intraocular lenses for correction of high myopia

AIM: To compare Visian lens(model V4 c) and Artiflex lens regarding quality(contrast sensitivity) and quantity(efficacy, predictability, safety and stability) of vision in correcting high myopia with recording and analysis of complications. METHODS: The comparative prospective study included 39 eyes of 23 patients with high myopia, 19 eyes had Visian lens implantation(model V4 c) and 20 eyes had Artiflex lens implantation. The inclusion criteria were high myopia(higher than 6.0 D) and stable refraction(<0.5 D change over one year). Outcomes included assessment of safety and efficacy indices, predictability, stability, contrast sensitivity and analysis of complications at postoperative 1 d, 1 wk and 1, 3, 6 and 12 mo. Selection of the type of phakic intraocular lens for patients was based on surgeons' preferences, which was no specific selection criteria. RESULTS: After 12 mo of follow up, difference in uncorrected and corrected distant visual acuity(CDVA) between both groups was statistically insignificant(UDVA for VisianV4 c and Artiflex lens were 0.33±0.2 logMAR and 0.37±0.2 logMAR respectively, P=0.59, CDVA for VisianV4 c and Artiflex lens were 0.155±0.1 logMAR and 0.147± 0.1 logMAR respectively, P=0.87). The efficacy index was 1.25 for VisianV4 c lens and 0.8 for Artiflex lens, 78.9% of eyes were within one diopter spherical equivalent in Visian V4 c lens group compared to 70% in the Artiflex lens group. No eye lost lines of CVDA proving a good safety index for both lenses(safety index was 1.67 for VisianV4 c lens and 1.34 for Artiflex lens). Difference in contrast sensitivity between both groups was statistically insignificant(P=0.15, 0.88, 0.27, 0.32 and 0.82 at five spatial frequencies). CONCLUSION: Both Visian ICL V4 c and Artiflex lensesare safe and effective with stable and predictable refraction and they have comparable contrast sensitivity outcomes with no vision threatening complications.

Role of short-wavelength filtering lenses in delaying myopia progression and amelioration of asthenopia in juveniles

AIM： To evaluate the positive effects of blue-violet light filtering lenses in delaying myopia and relieving asthenopia in juveniles. METHODS： Sixty ametropia juveniles （aged range, 11-15y） were randomized into two groups： the test group （30 children, 60 eyes）, wearing blue-violet light filtering lenses; and the control group （30 children, 60 eyes）, wearing ordinary aspherical lenses. Baseline refractive power of the affected eyes and axial length of the two groups was recorded. After 1-year, the patients underwent contrast sensitivity （glare and non-glare under bright and dark conditions）, accommodation-related testing, asthenopia questionnaire assessment, and adverse reaction questionnaire assessment. RESULTS： After ly of wearing the filtering lenses, changes in refractive power and axial length were not significantly different between the two groups （P〉0.05）. Under bright conditions, the contrast sensitivities at low and medium- frequency grating （vision angles of 6.3, 4.0, and 2.5） with glare in the test group were significantly higher than in the control group （P〈0.05）, while the contrast sensitivity at low-frequency grating （vision angles of 6.3 and 4.0） in the absence of glare in the test group was higher than in the control group （P〈0.05）. Under glare and non-glare dark conditions, the contrast sensitivities of various frequencies in the test group did not show significant differences compared with those in the control group （P〉0.05）. In the test group, the amplitude of accommodation, accommodative lag, and accommodative sensitivity of patients wearing glasses for 6 and 12mo were significantly elevated （P〈0.05）, while the asthenopia gratings were significantly decreased （P〈0.05）. Nevertheless, in the control group,the amplitude of accommodation, accommodative lag, and accommodative sensitivity after 12mo were not significantly altered compared with baseline （P〉0.05）, and the asthenopia grating was not significantly decreased （P〉0.05）. In addition, after wearing glasses for 6 to 12mo, the asthenopia grating of patients in the test group decreased significantly compared with the control group （P〈0.05）. At 12mo, the constituent ratio of adverse reactions did not show significant difference between the two groups （P〉0.05）. CONCLUSION： A l-year follow-up reveal that compare with ordinary glasses, short-wavelength filtering lenses （blue/ violet-light filters） increase the low- and medium-frequency contrast sensitivity under bright conditions and improved accommodation. They effectively relieved asthenopia without severe adverse reactions, suggesting potential for clinical application. However, no significant advantages in terms of refractive power or axial length progression were found compared with ordinary aspheric lenses.

Higher order aberration comparison between two aspherical intraocular lenses: MC6125AS and Akreos advanced optics

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.

Distance vision after bilateral implantation of AcrySof toric intraocular lenses:a randomized,controlled,prospective trial

·AIM:To evaluate the distance vision of Chinese patients with cataracts and corneal astigmatism after implantation of bilateral AcrySof toric intraocular lens (IOL) versus bilateral AcrySof spherical IOL.·METHODS:This study randomized 60 patients into equal groups to receive toric IOL or spherical IOL.IOL powers targeting emmetropia were selected for 93% of toric IOL patients and for 90% of spherical IOL patients.Assessments included monocular and binocular distance vision,with and without best correction.Patients also completed surveys about their distance vision.·RESULTS:Preoperatively,the two study groups were similar in age,in distance visual acuity,and in the magnitude of corneal astigmatism.At 6 months postoperative,binocular uncorrected distance vision was 0.06?à0.14 logMAR in the AcrySof toric IOL group,significantly better than the 0.14?à0.11 logMAR in the spherical IOL group (P<0.05).For eyes with emmetropia as a target,the equivalent of 20/20 uncorrected vision was more likely (P<0.001) in the toric IOL group (36% of eyes) than in the spherical IOL group (4% of eyes).No patients in the emmetropia/toric IOL group used distance glasses,as compared to 52% of patients in the emmetropia/spherical IOL group.All patients were satisfied or highly satisfied.Quality of distance vision was rated higher by toric IOL patients than by spherical IOL patients (P<0.05).·CONCLUSION:Bilateral AcrySof toric IOL is superior to bilateral spherical IOL in providing uncorrected distance vision to cataract patients with corneal astigmatism.·

Study on the surface properties of surface modified silicone intraocular lenses

AIM: To prepare a new-type soft intraocular lens (IOL) that silicone intraocular lenses (IOLs) were modified by surface modification technique to assess IOLs biocompatibility. METHODS: With the technique of ion beam combined with low temperature and low pressure plasma, the surface characteristics of the IOLs including physical and optical properties were determined by the instruments of IOLs resolution, UV/VIS scanning spectrophotometer, contact angle measurement system, electron spectroscopy for chemical analysis (ESCA) and scanning electron microscope (SEM). RESULTS: The color of titanium (Ti) modified IOLs was light yellow and that of titanium nitride (TiN) modified IOLs was light brown. The absorptive degree of ultraviolet rays and the hydrophilicity of the surfaces of modified IOLs were increased, and appeared suitable chemical compositions. The resolution of unmodified and modified IOLs reached normal standard. The surfaces of unmodified and Ti-modified IOLs appeared uniform. The surfaces of TIN-modified IOLs presented fine porcelain structure. CONCLUSION: The optical properties of all IOLs and the surface morphology of the modified IOLs were not affected by modification processes. The surface properties of the modified IOLs were improved.

F-heparin modified intraocular lenses in Rhesus monkeys

AIMIn order to improve the biocompatibility of intraocular lenses (IOL), the polymethylmethacrylate (PMMA) IOL was modified with F-heparin.

Numerical simulation of cyclic behavior of double sand lenses and corresponding liquefaction-induced soil settlement

A two-dimensional numerical model was used to explain the liquefaction mechanism of double sand lenses and the corresponding soil deformation due to the cyclic loading. Moreover, in order to investigate the influences of the soil characteristics and input loading data a parametric study was carried out on the essential parameters affecting the soil settlement, and so the variation of these parameters with the corresponding displacements was mainly examined. At last, the results obtained from the numerical analyses of double sand lenses and a continuous sand layer with similar characteristics were compared with those of an estimating method proposed by ISHIHARA and YOSHIMINE. The comparisons show that the settlements due to liquefaction of the continuous sand layer in both numerical and the estimating method are in a good agreement with and are obviously greater than those of double sand lenses.

Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses

AIM： To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses.METHODS： Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device （LAMBDA-X, Belgium）. Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance （far, intermediate, and near） and pupil size was also analyzed.RESULTS： The power distribution of the lenses was affected by pupil size differently. One of the lenses showed a significant spread in refractive power distribution, from about ？3 D to 0 D. Generally, the power distribution of the lenses expanded as the pupil diameter became greater. The surface of the lens dedicated for each distance varied substantially with the design of the lens.CONCLUSION： In an experimental basis, our results show how the lenses power distribution is affected by the pupil size and underlined the necessity of careful evaluation of the patient’s visual needs and the optical properties of a multifocal contact lens for achieving the optimal visual outcome.