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.

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.

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.

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.

老视发病机制及防治方法的研究进展

老视是一种随着年龄增长,眼晶状体的弹性和可塑性下降,睫状肌功能变弱,导致近距离工作和阅读发生困难、视物不能持久、易出现视疲劳的疾病。本文对老视的发病机制及防治方法进行综述,发现影响老视的因素主要有年龄、性别、疾病和药物等,治疗方法主要包括光学矫正、手术和药物治疗,均可在一定程度上改善老视的视近困难。目前,光学矫正是最常见治疗方法,矫治手术分为角膜手术、晶状体手术和巩膜手术,均存在着一定的限制和风险。药物治疗包括缩瞳类药物、恢复晶状体弹性药物以及中药,但多处于研究阶段。本研究通过对老视发病机制及防治方法的总结,可为未来的临床研究及治疗提供思路。

浅析检影验光中模拟眼与人眼的区别

模拟眼和人眼有本质区别,模拟眼是1个简单的屈光系统,检影上手容易;而人眼不仅仅是1个屈光系统,还有晶体调节、瞳孔变化等机制,人眼检影操作困难。模拟眼检影是检影验光学习的基础,只有充分掌握检影技巧,熟练检影后才可以进行人眼检影。

Multiple methods of surgical treatment combined with primary IOL implantation on traumatic lens subluxation/dislocation in patients with secondary glaucoma

AIM:To describe clinical findings and complications from cases of traumatic lens subluxation/dislocation in patients with secondary glaucoma,and discuss the multiple treating methods of operation combined with primary intraocular lens(IOL)implantation.METHODS:Non-comparativeretrospectiveobservational case series.Participants:30 cases(30 eyes)of lens subluxation/dislocation in patients with secondary glaucoma were investigated which accepted the surgical treatment by author in the Ophthalmology of Xi’an No.4Hospital from 2007 to 2011.According to the different situations of lens subluxation/dislocation,various surgical procedures were performed such as crystalline lens phacoemulsification,crystalline lens phacoemulsification combined anterior vitrectomy,intracapsular cataract extraction combined anterior vitrectomy,lensectomy combined anterior vitrectomy though peripheral transparent cornea incision,pars plana lensectomy combined pars plana vitrectomy,and intravitreal cavity crystalline lens phacofragmentation combined pars plana vitrectomy.And whether to implement trabeculectomy depended on the different situations of secondary glaucoma.The posterior chamber intraocular lenses(PC-IOLs)were implanted in the capsular-bag or trassclerally sutured in the sulus decided by whether the capsular were present.Main outcome measures:visual acuity,intraocular pressure,the situation of intraocular lens and complications after the operations.RESULTS:The follow-up time was 11-36mo(21.4±7.13).Postoperative visual acuity of all eyes were improved;28 cases maintained IOP below 21 mm Hg;2cases had slightly IOL subluxation,4 cases had slightlytilted lens optical area;1 case had postoperative choroidal detachment;4 cases had postoperative corneal edema more than 1wk,but eventually recovered transparent;2 cases had mild postoperative vitreous hemorrhage,and absorbed 4wk later.There was no postoperative retinal detachment,IOL dislocation,and endophthalmitis.CONCLUSION:To take early treatment of traumatic lens subluxation/dislocation in patients with secondary glaucoma by individual surgical plan based on the different eye conditions would be safe and effective,which can effectively control the intraocular pressure and restore some vision.

Age-related changes in the kinetics of human lenses:prevention of the cataract

The crystalline lens is a transparent,biconvex structure in the eye that,along with the cornea,helps to refract light to be focused on the retina and,by changing shape,it adjusts focal distance（accommodation）.The three classes of structural proteins found in the lens areα,β,and γ crystallins.These proteins make up more than 90% of the total dry mass of the eye lens.Other components which can be found are sugars,lipids,water,several antioxidants and low weight molecules.When ageing changes occur in the lens,it causes a gradual reduction in transparency,presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye.The main changes that occur with aging are： 1） reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2）crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3）production of advanced glycation end products（AGEs）,lipid accumulation,reduction of reduced glutathione content and destruction of ascorbic acid.Even if effective strategies in preventing cataract onset are not already known,good results have been reached in some cases with oral administration of antioxidant substances such as caffeine,pyruvic acid,epigallocatechin gallate（EGCG）,α-lipoic acid and ascorbic acid.Furthermore,methionine sulfoxide reductase A（MSRA） over expression could protect lens cells both in presence and in absence of oxidative stress-induced damage.Nevertheless,promising results have been obtained by reducing ultraviolet-induced oxidative damage.

Identification of the preferentially targeted proteins by carbamylation during whole lens incubation by using radio-labelled potassium cyanate and mass spectrometry

AIMTo attempt to identify the primary targets of carbamylation in bovine lenses incubated under physiological condition.

The effect of lens aging and cataract surgery on circadian rhythm

Many organisms have evolved an approximately 24-hour circadian rhythm that allows them to achieve internal physiological homeostasis with external environment.Suprachiasmatic nucleus（SCN） is the central pacemaker of circadian rhythm,and its activity is entrained to the external light-dark cycle.The SCN controls circadian rhythm through regulating the synthesis of melatonin by pineal gland via a multisynaptic pathway.Light,especially shortwavelength blue light,is the most potent environmental time cue in circadian photoentrainment.Recently,the discovery of a novel type of retinal photoreceptors,intrinsically photosensitive retinal ganglion cells,sheds light on the mechanism of circadian photoentrainment and raises concerns about the effect of ocular diseases on circadian system.With age,light transmittance is significantly decreased due to the aging of crystalline lens,thus possibly resulting in progressive loss of circadian photoreception.In the current review,we summarize the circadian physiology,highlight the important role of light in circadian rhythm regulation,discuss about the correlation between age-related cataract and sleep disorders,and compare the effect of blue light-filtering intraocular lenses（lOLs） and ultraviolet only filtering lOLs on circadian rhythm.

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

Acute lens-induced glaucomas: A review

Lens-induced factors are important and common mechanisms causing acute elevation of intraocular pressure. While in most cases, the diagnosis and management are straight-forward, in others it is difficult and can lead to improper procedures, complications and poor visual outcomes. This review was done with the aim of studying the various types of lens-induced glaucomas, classifying them in an easy way to understand manner, their clinical features, current management and future possibilities.

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.

Patterns of synuclein expression throughout lens development

Synucleins belong to a family of small soluble proteins with chaperonic activity implicated in human diseases, but their normal function is not completely understood. Expression of ?, ? and ?-synucleins was analyzed in rat and human lens on different stages of development. No significant expression of ?- and ?-synucleins were found, whereas ?-synuclein was expressed in both species only on early stages of lens development. Examination of ?-synuclein upstream region demonstrated the similarity in its organization with promoter regions of crystallins and heat shock protein’s genes. ?-Synuclein upstream region contains motives identical or similar to regulatory cis-elements in their promoters including binding sites for Pax6 and Sox. These results suggest that ?-synuclein plays a role in distinct temporal events in lens development, presumably acting as a specific chaperone.

Broccoli sprouts juice prevents lens protein aggregation in streptozotocin-induced diabetic rat

AIM: To investigate the effect of broccoli sprouts juice in preventing lens protein aggregation in diabetic rat model.METHODS: Totally 25 male Wistar rats were divided into negative control group, diabetic group without juice treatment as positive control and diabetic group given broccoli sprouts juice 0.25, 0.5 and 1 g/d for 28 d. Diabetic rat model was obtained by administering a single dose streptozotocin 65 mg/kg intraperitoneal. At the end of the study, all rats were examined for fasting blood sugar level(FBS), visual cataract score using slit lamp biomicroscope and lens αB-crystallin expression using Western blot method. Statistical analysis was performed using one way ANOVA with post hoc test, correlation test, and simple linear regression.RESULTS: Positive control group had the highest cataract score and lens aggregated αB-crystallin expression. Broccoli sprout juice dose of 1 g/d group had the mildest cataract score, as well as the expression of lens aggregated αB-crystallin compared to treatments groups 1 and 2, opposite to lens native αB-crystallin expression. The broccoli sprout juice groups gave a significant decrease in cataract score, and also in lens aggregated αB-crystallin expression in diabetic rat models(P<0.05). CONCLUSION: Broccoli sprout juice has a significant effect in preventing lens protein aggregation in diabetic rat model. The higher dose gives better visual cataract scores, lower lens aggregated αB-crystallin expression and higher lens native αB-crystallin expression.

Comparative Studies of the Carbohydrate of Human Gamma-Crystallins from Fetal and Adult Lenses with Agglutinins

Using gel chromatography of Sephadex G-75 superfine connectedwith Sephadex G-50 fine column,three human γ- crystallins(γ1,γ2,γ3)couldbe obtained.Seven agglutinins(LCA,SBA,DBA,PNA,BSL,RCA and UEA)were used to detect the sugar of sub-γ-crystallins,which had been transferredto nitrocellulose membrane and finally stained with ABC reagents and the sub-strate of HPR.These results suggested that γ2-and γ3-crystallin contain sugar,but γ1-crystallin has no sugar.There is a decrease of carbohydrate of γ2 and γ3as...

Potassium Iodide and Acrylamide Fluorescence Quenching Studies on Gamma-Crystallins of Human Lenses in Development and Aging

γ_1-γ_2-and γ_3-crystallin(corresponding to γs-,γC-and γD- crys-tallin respectively)of human fetal,2 year and 20^+ year old lenses areseparated by Sephadex gel chromatography.lodide and acrylamide are usedto quench the tryptophane fluorescence of sub-γ-crystalline fractions and Ksvand fa values are calculated.The results show that iodide has no clear quench-ing effects on all γ-crystallins,the quenching effects of acrylamide on the tryp-tophan fluorescences of γ1-γ2-and γ3-crystallin from lenses of the ...

Distribution of Human Lens Crystallins and Their Sulphydryl Contents of Different Age in Two-dimension Electrophoresis

Purpose: To analyze water-soluble(WS) human lens proteins of fetus, adult and age-related cataract by two-dimensional IEF/SDSPAGE electrophoresis. Methods: DACM [ N- (7-Dimethylamino-4-methyl-3-coumarinyl) maleimide ] was used to determine the lens proteins sulphydryl (SH) content.Result: Protein SH contents in WS lens proteins have no significant difference among fetus, adult and age-related cataract lens. This is different from the relative published results obtained in lens proteins of animal cataract model using similar SH detecting methods.Conclusions: IEF/SDS-PAGE electrophoresis demonstrated that there were much more fragmentation of crystallins during lens development and cataractogenic process. It is suggested that this phenomenon is likely to be due to further conformational changes in the fragmented cyrstallins during aging and cataractogenic process. Eye Science 1999; 15:32-35.