Paired comparison of contrast sensitivity in diffractive multifocal IOLs and conventional monofocal IOLs

Multifocal intraocular lens (IOL) optics produce a retinal image of reduced contrast, which results from splitting incoming light between multiple focal points. This study sought to determine whether the reduced-contrast image results in functional loss of contrast sensitivity. Contrast sensitivity was measured in patients in the US Food and Drug Administration (FDA) study of the 3M Diffractive IOL, using the Pelli-Robson Letter Chart. Fifty-eight of these patients, including six from our clinic, were 'best-case' patients with no pathology, and also had paired multifocallmonofocal implants. Data from these 'best-case' patients with paired eyes indicate no functional difference in contrast sensitivity. Additional data obtained on our six patients with the Regan Low Contrast Charts suggest small predictable differences may exist for some patients at very low contrast levels. Further study is needed to determine whether these differences have functional significance.     

视觉对比敏感度的临床应用

视觉对比敏感度比标准视力表检查能够更加敏感、真实地反映及评估视功能情况。目前研究已显示其在白内障、青光眼、屈光不正、斜视、弱视及视网膜病变等眼病的早期诊断和疗效评价等诸多领域具有应用价值。本综述结合新近相关文献,概述了视觉对比敏感度在上述领域的应用。     

一种新型的可检测不同人工晶状体植入术后功能视力的模型眼

目的:通过这种新型的模型眼比较各种人工晶状体(以Tecnis为代表的非球面晶状体、以Array为代表的多焦晶状体及以EPOCH为代表的传统单焦球面晶状体)植入术后的功能视力。方法:我们这种新型的模型眼是根据理论模型眼的光学特性设计而来的。该模型眼是由一个焦距为35mm的球面设计的摄影镜头、一个置于房水的人工晶状体、一个电荷耦合照相机(CCDcamera)构成,图像分析采用目前国际上标准的商业化遥感处理软件系统。结果:模型眼和人眼具有相似的调制传递函数(modula-tiontransferfrequency,MTF)。模型眼所成的像和植入人工晶状体的眼睛所成的像相似,光阑的孔径和人工晶状体的屈光度可以改变,也可将镜片置于摄影镜头之前。结论:该模型眼能够即时的给出人工晶状体植入术后所成的像,让我们可以直接观察到模型眼构成的图像而不是数据,并能显示出各种人工晶状体的差异。     

Eye Model for Inspecting the Image Quality of IOLs

Purpose:To inspect and compare the image quality of an aspheric intraocular lens(IQ,Alcon)with those of conventional monofocal silicone and acrylic intraocular lens and multifocal intraocular lens(Array).Methods:The IOLs were tested in the eye model,which was designed to be optically equivalent to the theoretical eye model.The eye model is a combination of a spherical photographic lens with 35 mm focal length(IOL put in a water cell)and a charge coupled device(CCD)camera.The images constructed by the lenses are observed on a monitor of personal computer and the contrasts of the images are analyzed by using commercial image processing software.SHARP value is used to measure and estimate image definition.Results:The images constructed by changing the diameter of aperture stop and IOL.Observed by this eye model,the image definition of aspheric intraocular lens(IQ,Alcon)is better than others.Discussion:The proposed eye model is useful for testing functional vision and for inspecting the differences of intraocular lens.     

非球面多焦点IOL眼的对比敏感度和拟调节力分析

目的评价白内障超声乳化摘出联合非球面衍射型多焦点人工晶状体植入术后患者的视觉质量和拟调节力。方法 54例(75眼)于我院行白内障超声乳化摘出联合人工晶状体植入术的患者进行分组,其中SN6AD3组17例(25眼)植入非球面多焦点人工晶状体Acrysof ReSTOR SN6AD3,SN60D3组18例(25眼)患者植入多焦点人工晶状体Acrysof ReSTOR SN60D3,SN60WF组19例(25眼)植入单焦点非球面人工晶状体Acrysof SN60WF。术后3个月时检查裸眼及矫正远视力、裸眼近视力、最佳矫正远视力下的近视力、拟调节力、对比敏感度,并比较3组患者脱近用镜率。结果术后3个月,三组患者裸眼远视力和最佳矫正远视力差异均无统计学意义(均为P>0.05);SN60D3组和SN6AD3组术后裸眼近视力(0.205±0.111、0.192±0.120)和最佳矫正远视力下的近视力(0.212±0.114、0.250±0.130)明显优于SN60WF组(0.661±0.278与0.661±0.278;均为P<0.01),SN60D3组和SN6AD3组间差异无统计学意义(P>0.05)。眩光及无眩光时,在各空间频率下SN60WF组和SN6AD3组对比敏感度均大于SN60D3组。SN6AD3组调节幅度为(0.925±0.549)D,SN60D3组为(0.964±0.582)D,SN60WF组为(0.390±0.235)D,SN6AD3组与SN60D3组间差异无统计学意义(P=0.993),SN6AD3组与SN60D3组的调节幅度均高于SN60WF组(P<0.01)。SN6AD3组脱近用镜率80%、SN60D3组72%,两组均优于SN60WF组(24%,均为P<0.01)。结论 ReSTOR非球面衍射型多焦点人工晶状体SN6AD3能提供良好的远、近视力,植入后术眼具有较SN60D3更高的对比敏感度,能有效改善白内障患者术后的视觉质量。     

Array人工晶状体眼调制传递函数和对比敏感度与瞳孔大小的关系

目的研究Array多焦点人工晶状体（SN-40N，AMO）术后调制传递函数（modulation transfer function，MTF）及对比敏感度（contrast sensitivity，CS）与瞳孔直径之间的关系。方法随访最近2年于我科行Array人工晶状体植入术的患者共124例（196眼），按严格的纳入标准选取研究对象，得到38例（57眼）。用iTrace视觉功能分析仪测量MTF及瞳孔直径，以iTrace3．1软件分析不同瞳孔直径下的MTF。用CGT-1000对比度眩光测试仪测量患者的对比敏感度及眩光敏感度,将患者按瞳孔直径≤3．5mm及〉3．5mm分为两组,比较两组患者的裸眼视力、最佳矫正视力、最佳矫正远视力下的近视力、波前像差及对比敏感度函数（contrast sensitivity function，CSF）。结果当瞳孔直径在2．0-3．5mm时，MTF随瞳孔增大而减小（P=0．000-0．025）；当瞳孔直径〉3．5mm时，MTF基本不变（P〉0．05）。瞳孔直径〉3．5mm组在最佳矫正远视力下有着更好的近视力（P=0．049），球差Z12较大（P=0．006），两组患者之间的CSF差异没有统计学意义（P〉0．05）。结论Array人工晶状体的调制传递函数及最佳矫正远视力下的近视力受到瞳孔大小的影响,但是.没有发现对比敏感度与瞳孔直径之间存在相关性。     

调制传递函数和对比敏感度函数评价LASIK术后早期视觉质量的研究

目的:应用调制传递函数(modulation transfer function,MTF)检查和对比敏感度函数(contrast sensitivity function,CSF)检查评价近视患者准分子激光原位角膜磨镶术(Laser in situ keratomileusis,LASIK)术后视觉质量的变化。方法:前瞻性研究。47例92眼行LASIK手术的患者按照术前验光度数分为低度近视组(A组)、中度近视组(B组)、高度近视组(C组)。术前等效球镜值分别为-2.28±0.48D,-4.54±0.97D,-6.86±1.17D。分别于术前,术后1wk;1,3mo检查裸眼视力(the uncorrected visual acuity,UCVA)、最佳矫正视力(best-corrected visual acuity,BCVA)、屈光度、波前像差、3mm和5mm瞳孔下的MTF和昼视及夜视视远状态下的CSF。利用德国Zeiss公司WASCAAnalyer波阵面像差仪检查三组患者在3mm和5mm瞳孔下去掉高阶像差后的MTF曲线,将图像扫描并载入至Engauge Digitizer4.1数字化软件,得出一定空间频率下的MTF值;利用Optical6500对比敏感度测试灯箱(美国STEREO OPTICAL公司)测量患者在昼视及夜视视远状态下的CSF值。对数据进行配对t检验。结果:(1)术后1wk,CSF值与术前相比有明显下降。术后3mo,只有明环境下低空间频率和暗环境下低中度近视组的低空间频率的CSF值可以恢复至术前。近视度数越高,中高空间频率的CSF值越不容易恢复至术前。(2)3mm瞳孔条件下低度近视组100L/mm,150L/mm,300L/mm空间频率的子午曲线和中度近视组50L/mm空间频率的子午曲线的MTF值,在术后7d与术前相比已经无统计学差异。3mm瞳孔条件下中度近视组150L/mm,200L/mm,300L/mm空间频率的弧矢曲线、高度近视组250L/mm空间频率下的子午曲线的MTF值和5mm瞳孔条件下低度近视组100L/mm,300L/mm,400L/mm空间频率下的子午曲线、中度近视组400L/mm,500L/mm空间频率下的弧矢曲线,200L/mm,400L/mm空间频率下的子午曲线,高度近视组全部空间频率下的弧矢曲线,100L/mm,200L/mm,300L/mm空间频率下的子午曲线的MTF值术后3mo可恢复到术前水平。其余所有空间频率下的MTF值均能在术后1mo恢复至术前水平。结论:(1)MTF值比CSF值恢复更早,只有部分低空间频率的CSF值可以恢复至术前,而所有的MTF值均能恢复至术前水平。(2)MTF值在术后早期可以更早更全面和客观的反映出视觉质量的提高。(3)利用Carl Zeiss公司WASCA Analyer波阵面像差仪检测患者MTF可以更立体全面客观的反映术后人眼光学系统的改变。     

Visual performance with simultaneous vision multifocal contact lenses

Purpose: The aim was to assess visual performance after PureVision high addition multifocal contact lens (PM) fitting through contrast sensitivity measured under different illumination levels for both distance and near. Methods: In a cross‐over study, 20 presbyopic patients were randomly assigned to PM or spectacles. Near contrast sensitivity was measured with the Vistech VCTS 6500 system. Distance contrast sensitivity and distance visual acuity (VA) were measured with the Functional Vision Analyser under photopic (85 cd/m²) and mesopic (3.0 cd/m²) conditions, the latter also under two levels of induced glare: 1.0 lux and 28 lux. Near VA was measured by logMAR charts under approximately 80 cd/m² luminance settings. Results: Average monocular spectacle corrected and PM VA were ‐0.02 ± 0.05 and 0.03 ± 0.05 logMAR for distance photopic, 0.16 ± 0.10 and 0.23 ± 0.07 logMAR for distance mesopic and ‐0.03 ± 0.05 and 0.05 ± 0.06 logMAR for near photopic, respectively. Average binocular spectacle corrected and PM VA were ‐0.05 ± 0.07 and ‐0.01 ± 0.03 logMAR for distance photopic, 0.10 ± 0.06 and 0.18 ± 0.05 logMAR for distance mesopic and ‐0.08 ± 0.06 and 0.02 ± 0.05 logMAR for near photopic, respectively. Statistically significant differences were found between the contrast sensitivity with the two types of correction for both distance and near, with spectacle correction being better in all cases. Conclusion: PureVision multifocal contact lenses preserve good VA and good visual performance under real‐life conditions.     

早期白内障患者对比敏感度测定及手术时机研究

目的 :前瞻性研究早期老年性白内障患者的手术前后视力、眩光和不加眩光下对比敏感度 (contrastsensitivityfunction ,CSF)的变化 ,探讨具有视觉影响主诉的早期白内障患者的手术时机。方法 :选择矫正视力在 0 .5及以上的早期老年性白内障患者 18例 2 3眼 ,作术前、术后 1个月加眩光和不加眩光的CSF测定。结果 :所有患者术前CSF值明显下降 ,在眩光下更加明显 ,各频段加眩光前后CSF值差异有非常显著性 (P <0 .0 1) ;术后CSF值恢复至正常范围 ,眩光与不加眩光下无明显差异 ,P >0 .0 5。所有患者术后视力均明显提高。结论 :CSF测定可以为视力表视力较好的早期老年性白内障患者提供客观依据。当白内障患者觉得视力变差影响日常工作、生活 ,而视力差的主要原因就是白内障时 ,即可考虑手术治疗     

Association of lens opacities,intraocular straylight,contrast sensitivity and visual acuity in European drivers

Purpose: To study the relationship between lens opacity and intraocular straylight, visual acuity and contrast sensitivity. Methods: We investigated 2422 drivers in five clinics in different European Union (EU) member states aged between 20 and 89 years as part of a European study into the prevalence of visual function disorders in drivers. We measured visual acuity [Early Treatment Diabetic Retinopathy Study (ETDRS) chart], contrast sensitivity (Pelli–Robson chart) and intraocular straylight (computerized straylight meter). Lens opacities were graded with the Lens Opacities Classification System III (LOCS) without pupillary dilation. Participants answered the National Eye Institute Visual Functioning Questionnaire – 25. Results: Intraocular straylight was related more strongly to LOCS score than to both visual acuity and contrast sensitivity. Visual acuity and contrast sensitivity were correlated to each other well, but to intraocular straylight to a much lesser extent. Self‐reported visual quality was best related to contrast sensitivity; night driving difficulty was best related to visual acuity. Conclusion: Straylight is found to have added value for visual function assessment in drivers, whereas if visual acuity is known contrast sensitivity has limited added value.     

Eye model for observing the images constructed by IOLs

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白内障眼的波前像差、对比敏感度及眩光敏感度研究

目的分析早期年龄相关性白内障患者的波前像差、对比敏感度和眩光敏感度改变。设计前瞻性病例对照研究。研究对象年龄相关性白内障患者62例(107眼),其中皮质性白内障组31例(50眼)、核性白内障组17例(32眼)、后囊下白内障组14例(25眼);正常对照组36例(36眼)。方法使用主观像差仪和自动眩光对比敏感度检查仪对受试者进行波前像差、对比敏感度及眩光敏感度检测。主要指标波前像差、对比敏感度及眩光敏感度。结果各组白内障患者整体像差和总高阶像差普遍高于正常对照组(P均<0．05)。皮质性白内障组和核性白内障第5阶像差高于正常组(P均<0．05)。所有受试者眩光敏感度均比对比敏感度下降明显(P均<0．05)。与正常组相比,皮质性白内障组的对比敏感度和眩光敏感度在低频段和中频段下降显著,核性白内障组的对比敏感度和眩光敏感度在低频段下降显著,后囊下白内障组的对比敏感度和眩光敏感度在全频段下降显著(P<0．05)。白内障组对比敏感度及眩光敏感度和高阶像差存在相关性,但在不同类型白内障,在对比敏感度和眩光敏感度的不同频段,在各阶像差中结果有所不同(r=-0．716-0．191,P<0．05)。结论早期白内障患者波前像差增高,对比敏感度及眩光敏感度下降。对比敏感度及眩光敏感度检查和波前像差测定结合进行,可有效、客观、定量地反映早期白内障患者的视觉质量下降。     

新标准下超声乳化术后人工晶状体眼视觉对比敏感度的研究

目的探讨新标准下超声乳化术后人工晶状体眼视觉对比敏感度（CSF）的变化。方法试验组超声乳化联合人工晶状体植入手术的白内障124例（139眼）,分为青、中和老年3个年龄组。术后3个月用对比敏感度测试仪行单眼昼、昼眩光、夜和夜眩光的4种状态下5种空间频率（1．5、3、6、12和18cpd）CSF测定,正常对照组是同年龄正常人74例（148眼）,双眼矫正视力均≥1．0。结果超声乳化术后患者CSF大致恢复到正常范围,但其值较正常对照组降低。3个年龄组昼及昼眩光状态低、中频（1．5、3、6cpd）超声乳化术后患者与正常对照组比较差异无统计学意义（P〉0．05）;高频（12、18cpd）比较P〈0．05,老年组在12cpd时P〉0．05。3个年龄组夜及宿眩光状态低频（1．5、3cpd）超声乳化术后患者与正常对照组比较P〈0．05,但老年岁组在3cpd时P〉0．05;6cpd比较各组差异P〉0．05,且不论超声乳化术后组还是正常对照组,CSF值随年龄增长均呈逐渐下降趋势。结论新测试标准下,超声乳化联合人工晶状体植入可恢复患者的CSF,但尚未达到同龄人正常水平。人工晶状体植入的设计原理对CSF的影响尚需要进一步探讨。     

Aurium变色人工晶状体植入术后对比敏感度和眩光对比敏感度的研究

目的 研究Aurium变色人工晶状体对术后对比敏感度和眩光对比敏感度的影响.方法 临床病例系列对比研究.选取2010年8月至2011年4月在南昌大学第二附属医院眼科就诊的白内障超声乳化联合人工晶状体植入术后患者,且随访资料完整的病例70例(眼),其中37例为Aurium (model400)变色人工晶状体组,33例为黄色蓝光滤过型IQ (SN60WF)人工晶状体组.观察患者术后3个月时的裸眼视力(UCVA),最佳矫正视力(BCVA),对比敏感度(CS)和眩光对比敏感度(GS).结果 二组患者术后3个月时的裸眼视力和最佳矫正视力差异均无统计学意义(P＞0.05).Aurium组和IQ组在明适应、明适应眩光、暗适应条件下,两组之间的对比敏感度和眩光对比敏感度差异无统计学意义(P＞0.05),在暗适应眩光条件下Aurium组的眩光对比敏感度(空间频率3 cpd、6 cpd)要优于黄色蓝光滤过型IQ组,差异有统计学意义(P＜0.05).结论 植入Aurium变色人工晶状体术后患者的视力与黄色蓝光滤过型IQ人工晶状体的视力差异无统计学意义.Aurium变色人工晶状体在暗适应眩光条件下,空间频率(3 cpd、6 cpd)的眩光对比敏感度要优于黄色蓝光滤过型IQ人工晶状体.     

对比敏感度和眩光敏感度在早期老年性白内障手术指征中的临床意义

目的探讨早期有症状的老年性白内障患者手术前后对比敏感度(contrastsensitivity,CS)和眩光敏感度(glaresensitivity,GS)的变化,为手术时机的选择提供科学依据。方法选择最佳矫正视力在0.5—1.0的42人共63眼,检查、分析患者术前1d及术后3w的视力、CS和GS。结果术前不同视力患者各频段的CS比较,仅高频段差异有显著意义(P<0.05),低、中频段差异无显著意义(P>0.05);各频段GS比较,差异无明显意义(P>0.05)。术后3周时视力、CS和GS较术前均明显提高,差异有显著意义(P<0.01)。虽然术前矫正视力为0.9～1.0的11眼与术后最佳矫正视力比较,差异无显著意义(P>0.05),但不同视角的CS及GS较术前均提高,差异有显著意义(P<0.05)。视力、CS、GS的变化与白内障的类型、混浊程度、部位、瞳孔大小密切相关,其客观量化仍需深入探讨。结论CS及GS检查可早期、灵敏、全面地反映早期老年性白内障患者的视功能状态,为早期有症状的老年性白内障患者确定手术时机提供科学依据,亦是评价手术疗效的有效标准。     

A clinical study to assess feasibility,acceptance, and outcome of multifocal intraocular lens in patients with bilateral immature cataract at a tertiary eye care institute

Purpose:To assess feasibility, acceptability, and outcome of multifocal intraocular lenses (IOL) in patients with bilateral immature cataract.Methods:1691 patients with bilateral immature cataract were included in the study. The feasibility of these IOLs was calculated by studying ocular parameters using Visionix VX120 and subjective characteristics. A prospective study was then conducted in 148 eyes of 74 patients in which multifocal IOLs were implanted. Their visual outcome was assessed using LogMAR for distance and Snellen''s chart for near vision, contrast sensitivity by Pelli-Robson chart, and satisfaction using visual function-7 questionnaire.Results:Considering ocular and subjective characteristics, it was feasible to implant the lens in 920 patients (54.40%) and the acceptability rate was 8.04%, most common reason for decreased acceptability was cost (85%) of IOL. The median distance uncorrected visual acuity (UCVA) at day 7 and at 30 days was LogMAR 0.2 (0.1–0.3) and 0.15 (0.1–0.2), respectively, which was statistically significant compared to preoperative distance UCVA (P < 0.001). The median near UCVA at day 7 and 30 days was N6 for both and statistically significant (P < 0.001) compared to preoperative near UCVA. 77.02% patients had distance UCVA of LogMAR (0.0–0.2) and 91.8% had near UCVA of N6–N8 at 30 days. The contrast sensitivity was decreased in all patients.Conclusion:Appropriately selected patients can achieve spectacle independence and good visual satisfaction which begins with proper patient education, lifestyle and personality dynamics, and individualized weighing of benefits and side effects of multifocal IOLs.     

矩形光栅法视网膜调制传递函数测定技术的研究

目的:证明利用矩形光栅法测定人眼视网膜-大脑调制传递函数(MTF)的有效性,从而可以开发出一种结构小巧、移动性好、价格便宜、性能稳定的MTF测量仪。方法:在实验室搭建实验装置,分别利用矩形光栅法的实验装置和平板法视网膜MTF测量仪器,来测定正视眼组和屈光不正组的不同空间频率条纹分辨的阈值,算出并分析比较所测MTF值。结果:用本实验装置所测量的MTF曲线特征符合人眼MTF的山型特点。在六个空间频率下用本实验装置所测的正视眼和屈光不正组的MTF值之间没有显著性差异,P >0.05。对于同一样本组,用本实验装置和平板法微机控制视网膜MTF测定仪所测量的视网膜MTF值之间比较没有发现显著性差异,P >0.05。结论:本实验装置经过试用证明,其性能稳定、结果正确、可避开屈光因素的影响、能有效反映人眼的MTF曲线特征,与以往方法所测MTF值的符合性好,从而证明了利用矩形光栅测量视网膜MTF的原理的正确性。     

全息光栅法视网膜调制传递函数测定装置的实验研究

目的验证在光学实验平台上利用全息光栅法及“0”级空间滤过法搭建的调制传递函数（modulation transfer function,MTF）测量装置的可行性,从而为今后该种仪器的顺利开发、生产做好相关理论和实验的基础工作。方法利用全息光栅法及“0”级空间滤过法在光具座上搭建视网膜调制传递函数测定实验装置．并进行一般人群测量,根据所测量结果与25例正常人（50眼）的调制传递函数进行比较分析。结果用本实验装置所测量的MTF曲线结果为：MTF的峰值位于中空间频率区6cpd,在低频区和高频区MTF呈下降趋势,曲线表现一倒置的“U”字形,符合人眼MTF的特点。结论本实验装置经过初步试用表明,利用全息光栅法及“O”级空间滤过法制作的视网膜调制传递函数测定装置所测人眼的MtF曲线特征,与正常人眼MTF值的符合性好,为今后开发基于全息光栅法及“O”级空间滤过法的人眼调制传递函数测量产品提供了可靠的实验依据。     

全视系统空间MTF测试系统设计

目的：介绍一种用VB程序编制的快速，简便，有效的全视系统黑白和色觉空间调制传递函数（MTF）测量系统设计方法。方法：按照调制传递函数MTF定义和Weber定律；采用矩形条纹作为视标（矩形条纹由VB编程实现）。对比度由计算机的像素灰度有别变化决定。将MTF的范围按对数等间隔分成13档，然后按公式分别计算每一档对应的前景和背景的灰度值，空间频率SF的设计由视标宽度，视标和被测者距离所决定。结果和结论：在计算机显示屏上显示出各种空间频率和各种对比度的矩形条纹（并保持它们平均亮度不变，条纹分黑白，红、绿、蓝四种，作为测量全视系统从3cpd到47．5cpd，分13档，按对数等份，沿X方向改变；MTF也分13档，沿Y方向改变，用本视标初步检测了20只正常眼，所得结果和文献报道相似，均呈带通型，但本研究应用方波条纹，因为其边缘能增强视知觉，使得视觉系统感效应，另外，在相同空间频率下，黑白全视系统MTF与绿色MTF相差不大，而红色MTF与绿色MTF、黑白MTF相比，MTF值降低，蓝色MTF曲线与上述三种比较，MTF值相关最大。