Transient vacuolar changes of the crystalline lens in patients using a dispersive ophthalmic viscosurgical device

AIM:To report the clinical prognosis and pathological findings of accidental lens vacuolar changes in eyes with intraoperative exposure to a dispersive ophthalmic viscosurgical device(OVD).METHODS:Two patients who developed transient lens vacuolar changes during uneventful persistent pupillary membrane(PPM)removal surgery were presented and followed up.This event was speculated to be associated with an intraoperative dispersive OVD DisCoVisc(hyaluronic acid 1.6%-chondroitin sulfate 4.0%)exposure.Then,to provide the pathological basis for our speculation,another four cataract patients were randomly exposed to different OVDs,and their anterior lens capsules were investigated with transmission electron microscopy(TEM).RESULTS:After months,the subcapsular vacuoles in both PPM cases were gradually disappeared without visual deterioration.For the cataract patients,similar lens changes were observed intraoperatively in those exposed to a dispersive DisCoVisc but not a cohesive OVD IVIZ(sodium hyaluronate gel 1.0%).In addition,marked ultrastructural changes,including chromatin condensation,extensive cytoplasmic vacuoles,and obvious intercellular space between lens epithelial cells in the anterior lens capsules of all eyes exposed to DisCoVisc,were observed by TEM.CONCLUSION:The lens vacuolar changes may be associated with a dispersive OVD exposure.Therefore,it is not preferable to use dispersive OVDs in patients with transparent lenses or without the intention of lens extraction.In addition,close follow-ups instead of immediate lens extraction are recommended for the occurrence of similar lens lesions.

Changes in crystalline lens parameters during accommodation evaluated using swept source anterior segment optical coherence tomography

Backgrounds:To assess changes in anterior segment biometry during accommodation using a swept source anterior segment optical coherence tomography(SS-OCT).Methods:One hundred-forty participants were consecutively recruited in the current study.Each participant underwent SS-OCT scanning at 0 and−3 diopter(D)accommodative stress after refractive compensation,and ocular parameters including anterior chamber depth(ACD),anterior and posterior lens curvature,lens thickness(LT)and lens diameter were recorded.Anterior segment length(ASL)was defined as ACD plus LT.Lens central point(LCP)was defined as ACD plus half of the LT.The accommodative response was calculated as changes in total optical power during accommodation.Results:Compared to non-accommodative status,ACD(2.952±0.402 vs.2.904±0.382 mm,P<0.001),anterior(10.771±1.801 vs.10.086±1.571 mm,P<0.001)and posterior lens curvature(5.894±0.435 vs.5.767±0.420 mm,P<0.001),lens diameter(9.829±0.338 vs.9.695±0.358 mm,P<0.001)and LCP(4.925±0.274 vs.4.900±0.259 mm,P=0.010)tended to decreased and LT thickened(9.829±0.338 vs.9.695±0.358 mm,P<0.001),while ASL(6.903±0.279 vs.6.898±0.268 mm,P=0.568)did not change significantly during accommodation.Younger age(β=0.029,95%CI:0.020 to 0.038,P<0.001)and larger anterior lens curvature(β=−0.071,95%CI:−0.138 to−0.003,P=0.040)were associated with accommodation induced greater steeping amplitude of anterior lens curvature.The optical eye power at 0 and−3 D accommodative stress was 62.486±2.284 and 63.274±2.290 D,respectively(P<0.001).Age was an independent factor of accommodative response(β=−0.027,95%CI:−0.038 to−0.016,P<0.001).Conclusions:During−3 D accommodative stress,the anterior and posterior lens curvature steepened,followed by thickened LT,fronted LCP and shallowed ACD.The accommodative response of−3 D stimulus is age-dependent.

Effects of wave propagation anisotropy on the wave focusing by negative refractive sonic crystal flat lenses

In this study, wave propagation anisotropy in a triangular lattice crystal structure and its associated waveform shaping in a crystal structure are investigated theoretically. A directional variation in wave velocity inside a crystal structure is shown to cause bending wave envelopes. The authors report that a triangular lattice sonic crystal possesses six numbers of a high symmetry direction, which leads to a wave convergence caused by wave velocity anisotropy inside the crystal. However, two of them are utilized mostly in wave focusing by an acoustic fiat lens. Based on wave velocity anisotropy, the pseudo ideal imaging effect obtained in the second band of the flat lens is discussed.

Theoretical demonstration of the hybrid focusing points of sonic crystal flat lenses and possible applications

We demonstrate the hybrid focusing points of sonic crystals for a multi-source array applied to flat sonic crystal lenses. The contributions of different point source couples form hybrid focusing points. Ray-trace analyses are conducted for acoustic flat lenses with multi-source configurations. The finite-difference time-domain （FDTD） simulation of flat lenses with multi-source configurations demonstrates the establishment of pure and hybrid focusing points in a pyramidal constellation. The number of focusing points in the pyramidal constellation depends on the number of point sources. We propose an acoustic device for fine-tuning the location of a far-field hybrid focusing point and discuss its benefits for acoustic energy focusing application.

Flat lenses constructed by graded negative index-based photonic crystals with tuned configurations

Flat lenses are designed by means of graded negative refractive index-based photonic crystals （PCs） constructed using air-holes tuned with different shapes. By gradually modifying the filling factor along the transverse direction, we obtain the graded negative index-based lenses for the purpose of focusing an incident plane wave. The finite-difference and timedomain （FDTD） algorithm is adopted for numerical calculation. Our calculation results indicate that these lenses can finely focus incident plane waves. Moreover, for the same size of air-holes, the focusing properties of the lens with rectangular air-holes are better than those with the other shaped air-holes. The graded negative index PCs lenses could possibly enable new applications in optoelectronic systems.

Tunability of graded negative index-based photonic crystal lenses for fine focusing

Graded negative refractive index-based photonic crystal （PC） lenses are designed by gradually modifying the sizes of air holes along the transverse direction for focusing the incident plane wave. To study the tunability of the graded negative index-based PC, we introduce filling factor A, gradually tune the filling factor, and use the finite-difference and time-domain （FDTD） algorithm for numerical calculation. Our calculation results indicate that the focal length and the spot size increase with A increasing. For the same A value, the focal length of a PC with elliptical air holes is the longest, and those of PC with square and rectangular air holes are the shortest. Moreover, when the focal length is greater than 1 ~xm, the focal parameters of the PC are highly insensitive to the variation of A. When the focal length is less than 1 gm, the PC lenses have higher transmittances and all well focus with a beam spot size breaking the diffraction limit. This feature possibly makes the graded negative index-based PC lenses have some new applications in optoelectronic systems.

Liquid crystal Fresnel lens display

A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display（LCFLD） with a holographic screen was demonstrated.The proposed display system has high efficiency,simple fabrication,and low manufacturing cost due to the absence of a polarizer and color filter.

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.

23-Gauge Pars Plana Vitrectomy Alone by a Bimanual Technique for the Removal of Dense Posteriorly Dislocated Crystalline Lens

Background: We sought to verify the efficacy and safety of transconjunctival 23-gauge pars plana vitrectomy (PPV) alone by our bimanual technique for the removal of dense posteriorly dislocated crystalline lens. Methods: A retrospective, noncomparative, interventional study of 31 consecutive cases of patients who underwent 23-gauge PPV alone for the removal of dense posteriorly dislocated crystalline lens following complicated cataract surgeries using our bimanual technique was conducted. The main outcomes measured included best-corrected visual acuity (BCVA), preoperative intraocular pressure (IOP), postoperative IOP and postoperative complications. Results: In all 31 cases included in this study, those dense posteriorly dislocated crystalline lenses were successfully removed. The enrolled patients consisted of 17 males and 14 females with a mean age of (75.84 ± 6.17) years (range 59 - 90). The mean follow-up length was (7.61 ± 1.87) months with a range of 6 months to 1 year. The mean preoperative BCVA was 0.22 ± 0.11 logMAR system, and the postoperative BCVA was 0.33 ± 0.07 logMAR system after 6 months of follow-up. The mean operative time was 46.32 ± 4.80 minutes with a range of 38.00 to 57.00 minutes. All of the conjunctival incisions self-closed within the first week with no wound leakage or hemorrhage. The postoperative complications were relatively rare. Conclusions: The removal of dense posteriorly dislocated crystalline lens might be a challenge for micro-incision vitrectomy. Our bimanual technique was proved to be an effective and safe method for those particular dense lenses using 23-gauge alone.

Preoperative evaluation of human crystalline lens hardness using A-scan ultrasound biometry： a pilot study

Dear Editor,I write to present the results of a study on the correlation between the ultrasound energy consumed during phacoemulsification with various preoperative parameters,including best corrected distance visual acuity（BCDVA）,the signal to noise ratio（SNR）obtained by partial coherence laser interferometry and primarily,lens spikes measurements derived by A-scan ultrasound biometry.Quantification of crystalline lens hardness before cataract removal has been attempted by several researchers in the past.These have been in humans and in animals,in vivo and in vitro,and have used a variety of imaging modalities.

Analysis of changes in crystalline lens thickness and its refractive power after laser in situ keratomileusis

AIM: To evaluate changes in the anterior chamber depth (ACD), crystalline lens thickness (LT) and its refractive power after laser in situ keratomileusis (LASIK). METHODS: In all cases, the preoperative and postoperative central ACD which were measured with Pentacam, Orbscan, IOL-Master and A-scan ultrasonography, central corneal true net power which was measured with the Pentacam, Orbscan and IOL-Master, axial length (AL) which was measured with IOL-Master and LT which was measured with the A-scan ultrasonography were compared using the paired sample t test. Ocular refractive errors and lens refractive power at corneal plane were calculated and their correlations were also evaluated before and after LASIK. RESULTS: At 1 week after LASIK, LT and crystalline lens refractive power at corneal plane (Dlens) which were associated with the IOL-Master and Pentacam increased significantly (P <= 0.005), ACD decreased significantly (P <= 0.001), but no significant increase was observed in the Diens which was associated with the Orbscan(P=0.261). Significant correlations between the changes in the ocular refractive errors and Diens which were associated with the Pentacam were observed at 1 week and 6 months after LASIK (P = 0.028; P=0.001). CONCLUSION: LT increased significantly after LASIK, and this might partially lead to ACD decrease, Diens increase and a small quantity of myopic regression.

Iatrogenic crystalline lens injury during intravitreal injection of triamcinolone acetonide: A report of two cases

BACKGROUND Intravitreal injection has become an efficient approach for delivering drugs at therapeutic levels to the posterior segment in retinal diseases.However,the increased frequency and number of intravitreal injections have raised concerns about their side effects.As manipulation during surgery is relatively simple,details of the procedure are easily overlooked.Iatrogenic crystalline lens injury is a rare complication caused by improper manipulation during surgical procedures.We report two cases of crystalline lens injury during intravitreal injection of triamcinolone acetonide(TA)with the hope of providing an insight into this treatment.CASE SUMMARY Case 1 was a 62-year-old woman with macular edema caused by central retinal vein occlusion in her right eye,and Case 2 was a 65-year-old man with macular edema caused by branch retinal vein occlusion in his right eye.In view of the patients’condition and economic constraints,an intravitreal injection of TA was administered.Due to inappropriate manipulation during surgery,the lens was injured.The site of lens injury and clinical manifestations were different in the two cases.Symptomatic treatment and continuous follow-up were carried out.The therapeutic effect following phacoemulsification of the cataract was satisfactory.CONCLUSION Well-defined surgical incision under proper anesthesia,sufficient patient information and proficient anatomical skills of the physician are mandatory to prevent this rare adverse event.Careful and meticulous phacoemulsification of the cataract is suggested.

Objective evaluation of the changes in the crystalline lens during accommodation in young and presbyopic populations using Pentacam HR system

AIM: To quantify the changes in the lens profile with accommodation in different age groups. METHODS: The Pentacam HR system was used to obtain the images of the anterior eye segment from 23 young and 15 presbyopic emmetropic subjects in unaccommodated (with an accommodation stimulus of 0.0D) and accommodated (with an accommodation stimulus of 5.0D for the young group and 1.0D for the presbyopic group) states. The phakic crystalline lens shape, including curvature of crystalline lens and central lens thickness (CLT), and the measurements of anterior segment length (ASL), central anterior chamber depth (CACD) were investigated. The anterior chamber volume (ACV) was also measured. RESULTS: The reduction of CACD and ACV were significant in both groups after accommodation stimulus. From the profile of anterior eye segment, a significant decrease in anterior crystalline lens radii of curvature (-2.52mm) and a mean increase in CLT (0.222mm) and ASL (0.1138mm) were found in the. young group with an accommodation stimulus of 5.0D. However, no statistically significant changes of CLT, ASL, or crystalline lens radii of curvature were found in the presbyopic group. CONCLUSION: Our data showed that the shallowing of anterior chamber during accommodation was caused by the forward bulging of the anterior lens surface, rather than by anterior shifting of lens position in either young or presbyopic subjects.

Large-scale SiO_2 photonic crystal for high efficiency GaN LEDs by nanospherical-lens lithography

Wafer-scale SiO2 photonic crystal （PhC） patterns （SiO2 air-hole PhC, SiO2-pillar PhC） on indium tin oxide （ITO） layer of GaN-based light-emitting diode （LED） are fabricated via novel nanospherical-lens lithography. Nanoscale polystyrene spheres are self-assembled into a hexagonal closed-packed monolayer array acting as convex lens for expo- sure using conventional lithography instrument. The light output power is enhanced by as great as 40.5% and 61% over those of as-grown LEDs, for SiO2-hole PhC and SiO2-pillar PhC LEDs, respectively. No degradation to LED electrical properties is found due to the fact that SiO2 PhC structures are fabricated on ITO current spreading electrode. For SiO2- pillar PhC LEDs, which have the largest light output power in all LEDs, no dry etching, which would introduce etching damage, was involved. Our method is demonstrated to be a simple, low cost, and high-yield technique for fabricating the PhC LEDs. Furthermore, the finite difference time domain simulation is also performed to further reveal the emission characteristics of LEDs with PhC structures.

Alteration of Crystallin Polypeptides in Rat Lenses during the Development of Galactose-induced Cataract

Some striking differences in relative polypeptide abundanceof crystallins were observed in normal and galactose-induced cataractouslenses of rat by means of SDS-PAGE.In the cataractous lenses aprominent band appeared at about 25 kDa and the αA chain increasedmarkedly,whereas the relative amount of the 31 kDa band decreasedsubstantially.These alterations are similar to the changes observed duringthe incubation of young mouse lenses in glucose-free medium.Eye Science1993;9:143-145.

Evaluating the Effects of Graviton Redshift upon Spiral Galaxy Rotation Curves, Surface Brightness Magnitudes and Gravitational Lensing

The effects of the gravitational redshift of gravitons upon spiral galaxy rotation energy are compared to the standard mass to light analyses in obtaining rotation curves. The derivation of the total baryonic matter compares well with the standard theory and the rotation velocity is matched to a high precision. The stellar mass distributions obtained from the fit with graviton energy loss are used to derive the surface brightness magnitudes for the galaxies, which agree well with the observed measurements. In a new field of investigation, the graviton theory is applied to the observations of gravitational lenses. The results of these applications of the theory suggest that it can augment the standard methods and may eliminate the need for dark matter.

Kerr-Lens Self-Mode-Locked Laser Characteristics of Yb:Lu_(2)SiO_(5) Crystal

A diode-pumped Kerr-lens self-mode-locked laser is achieved by using Yb:Lu2SiO5(Yb:LSO)crystal without additional components.Under the incident pump power of 14.44 W,a self-mode-locked output power of 2.98 W is obtained in the five-mirror cavity,corresponding to an optical-optical efficiency of 20.6%.Pulses as short as 8.2 ps are realized at 1059 nm,with the corresponding pulse energy and peak power of 28.9 nJ and 3.5 kW,respectively.A pair of SF10 prisms are inserted into the laser cavity to compensate for the group velocity dispersion.The pulse width is compressed to 2.2 ps with an average output power of 1.25 W.

Lens-Like Effect in LiNbO_(3) : Fe Photorefractive Crystal

The lens-like effects,both photorefractive effect and thermo-optical effect,were studied in the LiNbO_(3):Fe sheet.The threshold light intensity above which the photorefractive effect was overwhelmed b-v the thermal effect was determined and the thermo-optical coefficient dn/dT is evaluated by the Z-scanning method.The limiting characteristics of LiNbO_(3):Fe sheet is examined.

Studies on Human Fetal Lens Crystallins Under Oxidative Stress and Protective Effects of Tea Polyphenols

Purpose: To investigate the oxidative modification of water-soluble crystallins of human fetal lens with H2O2 and fourteen metal ions with or without EDTA. Tea-polyphenols (TP) was added to above solutions in order to testing their antioxidative abilities. Methods: The experiments were performed at 37℃ with final concentration of 2.5mg/ml protein, 0.1 mM metal ions, 0.3 mM EDTA and 1.0 mM H2O2. Then the TP was added to the solution with CuSO4 and H2O2, after 5 or 24 hours, the crystallins were analysed with SDS-PAGE and IEF.Results : There were marked oxidative modifications of lens protein in H2O2 and copper without EDTA. In SDS-PAGE patterns, we found an increase in those species above of bands higher than 30 kD and some diffuse bands from 30 to 17 kD after 5 hours. In IEF patterns, there were a general increase on acidity with loss of the more basic species. When the TP was added, there was not any difference with control group.Conclusion: The results indicate that exposure of water-soluble

Thermal Lensing Measurement and Laser Performance of End-Pumped Lightly Doped Nd:GdVO_(4) Crystal

The thermal lensing effect generated in an end-pumped lightly doped Nd:GdVO4 crystal was found to be considerably weaker than that in Nd:YVO4 having the same Nd3+ concentration. Consequently, the laser performance of Nd:GdVO4 at high pump powers over 20 W was found to be superior to that of Nd:YVO4. TEM00 mode cw radiation of 14.3 W at 1.06μm was achieved with an optical conversion efficiency of 55%, and average slope efficiency of 62%.