近视散光患者角膜形态对高阶像差的影响

目的 探讨近视散光患者高阶像差的分布特点及角膜形态对其的影响.方法 用wavescan wavefront system波前像差仪对LASIK术前281例（434眼）近视散光患者进行客观测量,用TMS-4角膜地形图仪获得角膜表面规则指数（surface regularity index,SRI）、角膜表面不对称指数（surface asymmetry index,SAI）以及角膜表面形态.对屈光度、SRI和SAI与高阶像差作相关分析,将患者分别按角膜形态分为5组,对各组间的高阶像差的均方根值（root mean square,RMS）作秩和检验.结果 6.0 mm瞳孔直径下的总高阶像差（root mean square of higher order aberrations,RMSh）的均方根值为（0.286±0.098）μm,从3阶至6阶大致呈递减趋势,其中以3阶彗差、三叶草和4阶球差的均数最大.屈光力和SRI与RMSh没有显著的相关性,SAI与RMSh呈正相关,Pearson相关系数为0.161,P值为0.001.SAI值对高阶像差的影响较SRI值大,尤其是SRI值较低的患者,RMSh值随SAI的增高而增大,主要表现为3阶彗差和4阶球差的增大.角膜形态为不规则形和不对称领结形时高阶像差最大,主要表现为三叶草和3阶彗差的增大.结论 6.0 mm瞳孔直径时,最主要的高阶像差是3阶彗差、三叶草和4阶球差.角膜形态为不规则形和不对称领结形时高阶像差最大.SAI对高阶像差的影响比SRI大.     

LASIK术后眼高阶像差和角膜非球面系数Q值的变化

目的:观察2mm小光斑飞点扫描伴主动眼球跟踪系统的激光机行常规LASIK术后,眼高阶像差和角膜非球面系数Q值的改变,同时观察术后不同瞳孔直径下眼高阶像差的变化。方法:近视患者33例60眼均接受常规LASIK手术,术前和术后3mo分别检查记录5mm和6mm瞳孔直径下总高阶像差、三阶彗差、四阶球差和角膜前表面非球面系数Q值,并进行统计学分析。结果:LASIK术后,5mm和6mm瞳孔直径下各高阶像差均较术前显著增加,其中四阶球差增加最为显著;术后水平彗差比垂直彗差增加显著;术前术后6mm直径下高阶像差均较5mm直径下显著增大;LASIK术后角膜非球面系数Q值向正值方向明显变化,差异具有显著性。结论:近视眼常规LASIK术后,各项高阶像差明显增大,其中球差增大最为显著。手术前后6mm瞳孔直径下高阶像差均比5mm瞳孔直径下高阶像差明显增大。术后角膜表面非球面系数Q值由负值变为正值,且增大显著。     

近视眼患者角膜高阶像差分布及LASIK和波前像差引导的优化LASIK术后高阶像差变化的研究

目的比较常规准分子激光原位角膜磨镶术（laserin situ keratomileusis,LASIK）和角膜波前像差引导的优化屈光角膜切削术（optimized refractive keratomy,ORK）后近视眼患者视力及角膜前表面高阶像差的变化,探讨角膜波前像差引导的优化准分子激光原位角膜磨镶术（ORK-LASIK）的安全性和有效性。方法选取拟做LASIK手术的近视眼患者396例733眼,按球镜屈光度分成低度（≤-3.00D）、中度（-3.00～-6.00D）和高度（-6.00～-12.00D）3组,每组柱镜度数均小于-2.50D,各组再随机分成2组,一组行常规LASIK手术,另一组行ORK-LASIK。手术切削区直径为6.0～7.0mm。角膜波前像差分析为6mm瞳孔直径。术后随访6个月,检查裸眼视力及角膜地形图并进行波前像差分析。结果成人近视眼角膜前表面波前像差在6mm瞳孔直径以3阶和4阶为主,占90%,在3阶和4阶中又以彗差和球差为主,分别占角膜全部像差的27.7%和28.4%;球差和球镜度数呈负相关（r=-0.501,P〈0.05）,其他高阶像差和球镜度数无关。但在-6.00D以上的近视眼中,彗差和次级彗差均和球镜度数有关（F=8.808,7.123,P〈0.04,0.01）。角膜前表面各高阶像差均和年龄及性别无关。LASIK和ORK-LASIK2组比较,术后6个月时,低度和高度组2组的裸眼视力均达到术前矫正视力,差异无统计学意义（P〉0.05）;在中度组,ORK-LASIK组视力明显好于LASIK组,2组差异有统计学意义（P〈0.05）。术后6个月时,角膜前表面的球差、彗差和总高阶像差均较术前增加,和术前比较差异有统计学意义（P〈0.05）。在低度组,ORK-LASIK组和LASIK组比较角膜彗差和球差2组间差异无统计学意义（P〉0.05）;中、高度组ORK-LASIK组角膜彗差和球差较LASIK组明显下降,差异有统计学意义（P〈0.05）。结论角膜波前像差引导的ORK-LASIK手术能有效地矫正近视和散光,提高中度近视患者的视力,降低中、高度组术后彗差和球差,手术效果稳定、安全。     

近视眼LASIK术后角膜像差变化的临床观察

目的研究准分子激光角膜原位磨镶术(laser insitu keratomileusis,LASIK)前后角膜像差的改变。方法对53例103眼施行LASIK手术的近视眼患者,采用角膜地形图及角膜像差系统检测术前、术后1周、术后1月角膜像差,分别记录直径为5mm、6mm、7mm时的角膜彗差、球差、总均方根值。结果角膜球差、彗差、总均方根术后均增加,术前、术后之间均有统计学差异(P<0.01),而术后1周与1月之间无统计学差异(P>0.05),且差值均随直径增大而增大;术后总均方根在角膜直径为5mm时较术前减小。结论研究的角膜范围越大,得出的角膜高阶像差值越大;术后除5mm范围内的总均方根值下降外,其余数值均高于术前;角膜彗差、球差、总均方根值在LASIK术后1周已基本趋于稳定。角膜像差的研究对指导个体化的近视激光治疗有着非常重要的意义。     

LASIK后角膜高阶像差改变分析

目的 探讨近视LASIK术后角膜高阶像差的变化情况.方法 回顾性分析近视LASIK手术患者75例145只眼,比较患者术前术后角膜非球面系数(Q值)、总体高阶像差均方根值(RMSh)、3～7阶像差均方根值(RMS3-RMS7)、球差、慧差、三叶草像差等数值,用多元线性回归分析筛选引起术后角膜高阶像差改变的因素.结果 术前角膜高阶像差与年龄无相关关系;术后各观察值的大小主要受术前相应各数值的大小、预矫屈光度数、切削区大小等因素的影响,术前值越大、预矫屈光度越大以及切削区越小,术后角膜高阶像差值越大;术后Q值、RMSh以及球差的增加量主要受预矫屈光度数和切削区大小的影响;慧差以及三叶草像差的增加与切削区大小无关.使用较小切削区(5.25mm)时的单位屈光度矫正引起的高阶像差增加值以及角膜前表而非球面系数改变值高于使用较大切削区时,差异有统计学意义.结论 LASIK术后角膜高阶像差增大,预矫屈光度数高和切削区小是引起术后角膜高阶像差增加较大的主要原因.     

不同屈光度近视SMILE术后1个月角膜屈光力分布及角膜高阶像差研究

目的比较低、中、高度近视患者飞秒激光小切口角膜基质透镜取出术(SMILE)术后1个月的角膜屈光力分布与角膜高阶像差。方法采用系列病例观察研究方法。选取209例SMILE患者的右眼入组,根据手术矫正等效球镜度(SE)分为低(SE<-3.0 D)、中(-3.0 D≤SE<-6.0 D)、高(SE≥-6.0 D)度近视3组,使用Pentacam眼前节分析系统测量与角膜中央直径4 mm环的平均屈光力相差0.5 D以内(△0.5 D)的角膜区域最大环直径及角膜高阶像差,分析不同近视分组术后角膜屈光力分布及其与角膜高阶像差变化的相关关系。结果低、中、高度近视组患者微透镜直径差异无统计学意义,矫正近视度数越高,△0.5 D分布最大环直径越小。术后角膜总高阶像差、球差和彗差较术前增加,术后球差在高度近视组明显增加,矫正近视度数越高,增加程度越大;术后三叶草差及变化值在3组患者中差异无统计学意义。△0.5 D分布最大环直径与手术前后角膜总高阶像差、球差、彗差的变化值呈显著负相关。结论SMILE矫正近视度数越高,术后产生良好视力的角膜范围越小,而术后角膜高阶像差越大,提示在矫正中高度近视时,确保安全前提下应设计较大直径微透镜,提高患者术后视觉质量。     

不同屈光度近视SMILE术后1个月角膜屈光力分布及角膜高阶像差研究

目的 比较低、中、高度近视患者飞秒激光小切口角膜基质透镜取出术(SMILE)术后1个月的角膜屈光力分布与角膜高阶像差。方法 采用系列病例观察研究方法。选取209例SMILE患者的右眼入组,根据手术矫正等效球镜度(SE)分为低(SE<-3.0 D)、中(-3.0 D≤SE<-6.0 D)、高(SE≥-6.0 D)度近视3组,使用Pentacam眼前节分析系统测量与角膜中央直径 4 mm环的平均屈光力相差0.5 D以内(△0.5 D)的角膜区域最大环直径及角膜高阶像差,分析不同近视分组术后角膜屈光力分布及其与角膜高阶像差变化的相关关系。结果 低、中、高度近视组患者微透镜直径差异无统计学意义,矫正近视度数越高,△0.5 D分布最大环直径越小。术后角膜总高阶像差、球差和彗差较术前增加,术后球差在高度近视组明显增加,矫正近视度数越高,增加程度越大;术后三叶草差及变化值在3组患者中差异无统计学意义。△0.5 D分布最大环直径与手术前后角膜总高阶像差、球差、彗差的变化值呈显著负相关。结论 SMILE矫正近视度数越高,术后产生良好视力的角膜范围越小,而术后角膜高阶像差越大,提示在矫正中高度近视时,确保安全前提下应设计较大直径微透镜,提高患者术后视觉质量。     

飞秒激光制瓣LASIK联合波前优化治疗近视及散光术后的角膜像差

目的 研究飞秒激光制瓣LASIK（飞秒LASIK）联合波前优化治疗近视及散光术后角膜像差的特性.方法 回顾性研究.行飞秒LASIK手术的近视及近视散光患者30例（30眼）,平均年龄（20.9±2.8）岁;术前平均等效球镜度（-6.48±1.61）D.应用Pentacam眼前节分析仪测量角膜前表面6、7、8、9 mm直径下的Q值,采用Keratron角膜波前像差分析仪测量6 mm瞳孔直径下角膜波前像差.随访时间为术后3个月,手术前后数据采用配对t检验,采用Pearson相关分析角膜像差、Q值与其他参数的相关性.结果 6 mm瞳孔直径下角膜高阶像差、总球差、总彗差、水平彗差、垂直彗差、初级球差、x-向次级像散、次级水平彗差、次级垂直彗差、次级球差均较术前增加,差异有统计学意义（t=-8.254、-7.385、-6.108、-5.651、-2.195、-7.565、-4.628、-2.974、-2.748、-7.068,P＜0.05）.角膜前表面4个直径范围内Q值均较术前增加,差异有统计学意义（t=16.999、-19.208、-21.502、-22.197,P＜0.05）.6 mm瞳孔直径下手术前后Q值变化量（△Q6mm）与高阶像差变化量、总球差变化量、初级球差变化量、总彗差变化量呈正相关（r=0.736、0.792、0.788、0.383,P＜0.05）,△Q6mm与总三叶草变化量、次级球差变化量无相关性（r=0.099、-0.348,P＞0.05）.结论 飞秒LASIK联合波前优化治疗近视及近视散光是安全、有效的,但术后角膜高阶像差仍有显著增加.     

角膜波前像差引导FS-LASIK治疗近视合并不同程度散光的疗效观察

目的:比较角膜波前像差引导的FS-LASIK手术治疗近视合并不同程度散光患者的术后疗效及角膜高阶像差的变化。方法:回顾性病例研究。选取2020-04/10在昆明爱尔眼科医院初次行角膜波前像差引导的FS-LASIK手术治疗近视合并散光患者133例265眼。根据散光程度分为三组：低散光组：散光度≤1.0D共62例124眼,中散光组：散光度1.25～2.0D共54例107眼,高散光组：散光度≥2.25D共17例34眼。记录患者术前及术后3mo时的视力及屈光度,使用Pentacam三维角膜地形图测量患者角膜,记录角膜6mm直径范围的总高阶像差(均方根)、球差、水平彗差、垂直彗差、水平三叶草差、倾斜三叶草差,观察三组患者术后效果并比较手术前后角膜高阶像差的变化情况。结果:三组患者术后视力的有效性指数均大于1.1,残余屈光度均在±0.30D以内,低散光组残余屈光度较其他两组最少(P<0.05)。术后3mo时三组患者的角膜总高阶像差、球差、垂直彗差较术前均增加(P<0.05)。高散光组术后的球差增量较其他两组最少(P<0.05)。结论:角膜波前像差引导的FS-LASIK手术矫正近视...     

近视散光患者眼球高阶像差的研究

目的了解国人近视散光患者眼球高阶像差的分布、瞳孔直径、近视、散光度数对高阶像差的影响。方法使用依据Tscherning原理设计的Allegretto Wave波前像差仪,对147只眼准分子激光原位角膜磨镶术(LASIK)前的近视散光情况进行检查,分别提取当瞳孔直径为4．0、4．5、5．0、5．0、5．5、6．0、6．5及7．0mm时高阶像差的均方根(RMS)值,根据近视和散光的度数高低分组对比研究分析。结果同一只眼内从3阶到6阶像差的RMS值呈递减趋势;同阶像差内最大值与最小值相差6．1至36．6倍;随着瞳孔的增大,高阶像差相应增加,尤其以3阶的彗差和4阶的球差增速快。当瞳孔小时近视度数只影响次级球差(第6级),随着瞳孔增大,近视度数既增加次级球差,也增加球差(第4级),当瞳孔直径≥5．0mm时,次级彗差(第五级)也增加,但在任何瞳孔直径下,近视度数对彗差无明显影响。散光度数对高阶像差的影响：当瞳孔直径≥6．5mm时,散光度数即使第3级彗差增加,也使第5阶的次级彗差增加,但在任何瞳孔直径下,散光度数对球差无明显影响。结论高阶像差在个体中存在较大差异,瞳孔直径、近视和散光程度对高阶像差有明显的影响。     

Segmentation and accuracy in copying and drawing: Experts and beginners

As part of an ongoing investigation into real-world copying and drawing, I recorded the eye-hand drawing strategies of 16 subjects with drawing experiences ranging from expert to novice while they copied a line drawing of a standing nude. The experts produced accurate copies whereas all the beginners produced marked inaccuracies of overall scaling, proportion and shape. Analysis of eye and hand movements showed that the experts alone segmented the original drawing into simple line sections that were copied one at a time using a direct eye-hand strategy not requiring intermediary encoding to visual memory. The results suggest that segmentation into simple lines defines the task-specific process of accurate copying, and that this process is restricted to experts, i.e. acquired through training and practice. Additional preliminary tests also suggest that a similar process may apply to drawing a model from life.     

Proximal and accommodative convergence and age

The authors have estimated the phoria for distant and near fixation in two groups of subjects (mean age 27.5 ± 4.4 and 59.2 ± 8.2 years). Different accommodative stimuli were induced by adding minus lenses for distant fixation and plus lenses for near fixation. Statistical analysis of the experimental data indicates that, for distant fixation, the value of phoria per unit of accommodative stimulus is significantly lower in presbyopic than in nonpresbyopic subjects. Also, during near fixation, the accommodative convergence (AC/A ratio) is more reliable in the presbyopic subjects when the accommodative stimulus is progressively reduced. This varying behavior indicates in presbyopic subjects that proximal convergence is of greater relative importance in the determination of the fusion-free position. In nonpresbyopic subjects, accommodative convergence is the more important component.     

Anesthesia and preoperative and postoperative medications

Although certain methods such as retrobulbar blocks are used extensively, improvements in procedure can always be implemented. The use of ultrasound, low concentrations of anesthesia, careful monitoring, and, in the case of risk patients, anesthesia standby are all important considerations to ensure uneventful treatments. Topical anesthesia eliminates needle risk as well as risk of ptosis and bruising. Because it has been demonstrated that bacteria routinely enter the anterior chamber during uncomplicated cataract surgery, certain irrigation solutions are helpful, but still debatable. Postoperatively, diclofenac, flurbiprofen, and timolol have all been proven to be effective in reducing ocular inflammation, reducing incidence of CME, and controlling pressure increase, respectively.     

Anesthesia and preoperative and postoperative medications

Retrobulbar blocks, although widely used, still have potentially serious complications. Topical anesthesia presents less risk of injury to the globe and less pain but requires careful usage and an experienced surgeon. New techniques, however, allow for an increase in the percentage of patients able to have topical anesthesia. Preoperatively, 2.5% phenylephrine is found to be just as effective as 10% phenylephrine, and, when compared with wound closure and surgeon's experience, the effect of prophylactic medications was found to be negated. Postoperatively, diclofenac is found to be as effective an anti-inflammatory agent as prednisolone. Also, the addition of 10% phenylephrine to 4% pilocarpine drops enhances the effectiveness of pharmacologic treatment of postoperative iridocorneal adhesions. In addition, ophthalmologists should be aware of emerging antibiotic resistance.     

Paraneoplastic and non-paraneoplastic retinopathy and optic neuropathy: Evaluation and management

Paraneoplastic syndromes involving the visual system are a heterogeneous group of disorders occurring in the setting of systemic malignancy. Timely recognition of one of these entities can facilitate early detection and treatment of an unsuspected, underlying malignancy, sometimes months before it would have otherwise presented, and gives the patient an increased chance at survival. We outline the clinical features, pathogenesis, and treatment strategies for the retinal- and optic nerve–based paraneoplastic syndromes: cancer-associated retinopathy; melanoma-associated retinopathy; paraneoplastic vitelliform maculopathy; bilateral diffuse uveal melanocytic proliferation; paraneoplastic optic neuropathy; and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome. Distinguishing these disorders from their non-paraneoplastic counterparts (e.g., autoimmune-related retinopathy and optic neuropathy, and acute zonal occult outer retinopathy) and determining appropriate systemic evaluation for the responsible tumor can be challenging. In addition, we discuss the utility and interpretation of autoantibody testing.     

Nodes and nodal points and lines in eyes and other optical systems

The typical stigmatic optical system has two nodal points: an incident nodal point and an emergent nodal point. A ray through the incident nodal point emerges from the system through the emergent nodal point with its direction unchanged. In the presence of astigmatism nodal points are not possible in most cases. Instead there are structures, called nodes in this paper, of which nodal points are special cases. Because of astigmatism most eyes do not have nodal points a fact with obvious implications for concepts, such as the visual axis, which are based on nodal points. In order to gain insight into the issues this paper develops a general theory of nodes which holds for optical systems in general, including eyes, and makes particular allowance for astigmatism and relative decentration of refracting elements in the system. Key concepts are the incident and emergent nodal characteristics of the optical system. They are represented by 2 × 2 matrices whose eigenstructures define the nature and longitudinal position of the nodes. If a system's nodal characteristic is a scalar matrix then the node is a nodal point. Otherwise there are several possibilities: Firstly, a node may take the form of a single nodal line. Second, a node may consist of two separated nodal lines reminiscent of the familiar interval of Sturm although the nodal lines are not necessarily orthogonal. Third, a node may have no obvious nodal line or point. In the second and third of these classes one can define mid-nodal ellipses. Astigmatic systems exist with nodal points and stigmatic systems exist with no nodal points. The nodal centre may serve as an approximation for a nodal point if the node is not a point. Examples in the Appendix , including a model eye, illustrate the several possibilities.     

Sensitivity to first- and second-order motion and form in children and adults

We compared the sensitivity of adults and children aged 3-10 years to first- and second-order motion and form. For first-order stimuli, at all ages sensitivity was better for motion than form, and motion thresholds were better at 6 Hz than at 1.5 Hz. For second-order stimuli, at all ages sensitivity was better for form than motion, and motion thresholds were better at 0.25 cyc/deg than at 1 cyc/deg. Thresholds became adult-like later for motion than for form and later for first-order than second-order stimuli. For first-order stimuli, the changes with age were larger and more protracted.     

Estrogen and progesterone receptors and human conjunctiva

Freshly frozen conjunctival tissue from premenopausal and postmenopausal women and male subjects were processed for estrogen and progesterone receptors by using monoclonal antibodies and a peroxidase-antiperoxidase technique. No immunocytochemical staining was localized in the nuclei of the cells treated with the monoclonal antibodies to human estrogen receptor or human progesterone receptor in any of the conjunctival specimens, in contrast to the strongly positive staining in breast adenocarcinoma controls. Immunocytochemical staining disclosed no evidence for estrogen or progesterone receptors on cells of the ocular surface.