三种仪器测量白内障术前角膜生物学参数的比较

目的：比较Pentacam、IOL Master和iTrace三种仪器测量白内障患者术前角膜曲率和散光的测量值的差异。

方法：前瞻性临床研究。收集白内障患者68例82眼，术前均接受IOL Master、Pentacam及 iTrace检查，测量患眼平坦轴角膜曲率(K1)、陡峭轴角膜曲率(K2)、角膜散光及轴向，计算平均角膜曲率(Km)、散光矢量 J0和J45，分析三种仪器测量结果的差异性、相关性和一致性。

结果：三种仪器测量的K1、K2、Km值均无差异(P>0.05)； 三种仪器测量的K1、K2、Km值均呈高度相关(|r|>0.5，P<0.01)，IOL Master与Pentacam、IOL Master与iTrace测量的J0、J45值均呈中度相关(0.3<|r|<0.5，P<0.01)，Pentacam与iTrace测量的J0、J45值均呈低度相关(0.1<|r|<0.3，P<0.05)； Bland-Altman分析法显示三种仪器测得K1、K2、Km、J0、J45一致性差。

结论：Pentacam、IOL Master和iTrace测量角膜曲率及散光之间具有相关性，但一致性差，不可任意替代使用，需根据患者眼部具体情况谨慎选择。     

不同像差分析设备对白内障患者角膜高阶像差测量的比较

目的: 比较新一代屈光分析仪OPD-ScanⅢ、扫频源眼前节光学相干断层扫描分析仪CASIA2与像差仪iTrace、三维眼前节分析仪Pentacam测量白内障患者角膜总高阶像差(tHOA)、角膜球面像差(SA)的差异性和一致性。方法: 系列病例研究。选取2021年5—8月在天津医科大学眼科医院白内障科行超声乳化白内障吸除联合人工晶状体植入术的白内障患者123例(123眼)。所有患者均采用iTrace、Pentacam、OPD-ScanⅢ和CASIA2测量角膜参数, 记录以角膜顶点为中心4 mm直径下的角膜tHOA及6 mm直径下的角膜SA的均方根(RMS)值。4种设备间测量结果的差异性分析采用两因素方差分析或Friedman检验, 相关性分析采用Person或Spearman相关分析。不同设备间测量结果的一致性评价采用Bland-Altman分析。结果: 4种设备测量角膜tHOA总体差异有统计学意义(Z=134.79, P<0.001)。两两比较显示, CASIA2和Pentacam测得的角膜tHOA差异无统计学意义, 且均高于OPD-ScanⅢ和iTrace(均P<0.0...     

不同角膜仪测量的角膜曲率值的一致性分析

目的：比较测得后三种不同角膜仪测量的角膜曲率,以评估其测量值之间的一致性。

方法：前瞻性研究。252例患者(252眼)使用IOL Master(IM),Bausch & Lomb手动角膜仪(Man)以及TOPCON KR-8800自动角膜仪(Top)进行角膜曲率测量。记录并对比平均角膜曲率值。使用Bland Altman统计方法进行仪器间的一致性分析。

结果：1)IOL Master 和 手动角膜仪：IOL Master平均角膜曲率为44.62±1.52 D,手动角膜仪为44.60±1.52 D。 t-test显示差异具有统计学意义(P=0.001); Bland-Altman图显示两种仪器间95%一致性区间(LOAs)为-0.22～0.22; 2)IOL Master 和自动角膜仪：IOL Master平均角膜曲率为44.62±1.52 D,自动角膜仪为44.46±1.53 D。t-test显示差异具有统计学意义(P<0.0001)。Bland-Altman图显示两种仪器间95%LOAs为 -0.24～0.55; 3)自动角膜仪和手动角膜仪：自动角膜仪平均角膜曲率为44.60±1.52 D,手动角膜仪为44.46±1.53 D。t-test显示差异具有统计学意义(P<0.0001)。Bland-Altman图显示两种仪器间95%LOAs为-0.30～0.57。

结论：使用不同的仪器获得的角膜曲率数据是不可替换的,这对于白内障外科医生在外科手术计划和结果评估方面具有重要意义。     

两种眼前节分析系统测量屈光手术前后波前像差的一致性

目的：研究SCHWIND和SIRIUS眼前节分析系统测量屈光手术患者手术前后像差结果的一致性。

方法：前瞻性对照研究。选取2017-06/12于四川大学华西医院眼科行飞秒制瓣准分子激光原位角膜磨镶术的屈光不正患者180例360眼,采用SCHWIND和SIRIUS眼前节分析系统测量角膜平轴和陡轴曲率的度数和轴向、Kappa角度数及高阶像差等数据。

结果：采用SCHWIND和SIRIUS眼前节分析系统测得的本组患者术前和术后1mo的角膜平轴度数和方向、陡轴度数和方向、术后1mo的Kappa角度数和方向、术前和术后1mo的彗差和三叶草数据差异均无统计学意义(P>0.05)。术前,两种检测方法检测的总高阶像差和球差数据差异均有统计学意义(P<0.01),SCHWIND测量值高于SIRIUS测量值; 术后1mo,两种检测方法检测的总高阶像差和球差数据差异均无统计学意义(P>0.05)。

结论：SCHWIND和SIRIUS眼前节分析系统测量屈光手术患者手术前后影响成像质量的相关数据具有较好的一致性。     

Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量瞳孔偏移量的对比研究

目的：评价Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量瞳孔偏移量(pupillary offset)的差异和一致性。

方法：随机选取2017-11/2018-02在我院行准分子激光原位角膜磨镶术(LASIK)的患者311例604眼。术前应用Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量患者瞳孔偏移量,比较两种仪器测量结果的差异性和一致性。

结果：Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量的右眼、左眼、双眼总的offset值均有差异(P<0.05)。两种仪器测量的右眼、左眼、双眼offset轴向均无差异(P>0.05)。两种仪器测量的右眼offset值、offset轴向95%一致性界线(LoA)分别为-0.11～0.19mm、-157.01°～135.35°。左眼offset值、offset轴向95% LoA分别为-0.12～0.18mm、-150.16°～158.22°。双眼offset值、offset轴向95%LoA分别为-0.11～0.19mm、-154.30°～147.10°。

结论：Pentacam眼前节分析仪测量的瞳孔偏移量比Keratron Scout角膜地形图仪的测量值小,差异在临床可以接受的范围内。两种仪器均可以获得准确的瞳孔偏移量数据,可相互参考、校正和补充。     

Pentacam与AS-OCT测量眼前节生物参数的比较

目的：在两组人群中比较Pentacam眼前节分析仪与眼前节光相干断层扫描(AS-OCT)测量的角膜曲率及角膜散光、中央角膜厚度和前房深度的差异性、相关性及一致性,为临床使用提供参考。

方法：前瞻性临床研究。纳入青年近视术前检查者64例124眼、年龄相关性白内障患者61例85眼,先后使用Pentacam和AS-OCT进行测量,获得眼前节生物参数。在两组人群中采用配对样本t检验分别对两种仪器测量结果的差异性进行比较,所得数据的相关性采用 Pearson相关性分析,测量结果的一致性采用 Bland-Altman 分析。

结果：近视组两种仪器测得的陡峭角膜曲率(Ks)、平坦角膜曲率(Kf)、平均角膜曲率(Km)有显著差异(P<0.001),而白内障组测得的Ks、Kf、Km无差异(P>0.05),两组人群两种仪器测量的J₀(散光参数)、平均角膜厚度(CCT)、前房深度(ACD)均有差异(P<0.05),测得J₄₅(散光参数)无差异(P>0.05)。两组人群中两种仪器测量的Ks、Kf、Km、J₀、J₄₅、CCT及ACD均具有线性相关(P<0.001)。近视组测量的Ks、Kf、Km的一致性良好,而白内障组测量的Ks、Kf、Km的一致性较差。

结论：Pentacam和AS-OCT测量散光参数、CCT及ACD时具有较好一致性,可互换使用,而测量Ks、Kf、Km时的一致性受年龄相关因素影响,优先考虑选择Pentacam。     

不同像差分析设备对白内障患者角膜高阶像差测量的比较

比较新一代屈光分析仪OPD-ScanⅢ、扫频源眼前节光学相干断层扫描分析仪CASIA2与像差仪iTrace、三维眼前节分析仪Pentacam测量白内障患者角膜总高阶像差（tHOA）、角膜球面像差（SA）的差异性和一致性。方法：系列病例研究。选取2021年5—8月在天津医科大学眼科医院白内障科行超声乳化白内障吸除联合人工晶状体植入术的白内障患者123例（123眼）。所有患者均采用iTrace、Pentacam、OPD-ScanⅢ和CASIA2测量角膜参数，记录以角膜顶点为中心4mm直径下的角膜tHOA及6mm直径下的角膜SA的均方根（RMS）值。4种设备间测量结果的差异性分析采用两因素方差分析或Friedman检验，相关性分析采用Person或Spearman相关分析。不同设备间测量结果的一致性评价采用Bland-Altman分析。结果：4种设备测量角膜tHOA总体差异有统计学意义（Z=134.79，P<0.001）。两两比较显示，CASIA2和Pentacam测得的角膜tHOA差异无统计学意义，且均高于OPD-ScanⅢ和iTrace（均P<0.001），OPD-ScanⅢ和iTrace测量结果差异无统计学意义。iTrace、Pentacam、OPD-ScanⅢ和CASIA2测量的角膜SA总体差异有统计学意义（F=114.72，P<0.001），结果分别为（0.291±0.079）μm、（0.445±0.147）μm、（0.310±0.092）μm和（0.277±0.131）μm。两两比较显示，OPD-ScanⅢ和iTrace、CASIA2和iTrace结果间差异均无统计学意义，其余各组间差异均有统计学意义（均P<0.05）。相关性分析显示，4种设备测量角膜tHOA和角膜SA均呈正相关性（r=0.27~0.69，均P<0.001）。Bland-Altman分析显示，iTrace与OPD-ScanⅢ测量角膜tHOA及角膜SA的95％一致性界限（95％LoA）分别为-0.11~0.09、-0.15~0.12，均显示临床可接受的一致性，4.07%~5.69%的测量值在95％LoA外，其余设备测量结果间95％LoA较宽，一致性较差。结论：OPD-ScanⅢ与iTrace测量以角膜顶点为中心4mm直径下的角膜tHOA和6mm直径下的角膜SA结果无差异，相关性及一致性好上，但除此之外的几种设备测量结果间差异性较大。     

Pentacam与IOL Master测量角膜屈光力的比较

目的：比较Scheimpflug 原理摄像系统Pentacam与光学相干生物测量仪IOL Master测量角膜正常的白内障患者角膜屈光力,分析两者的一致性。

方法：前瞻性临床研究。选取我院2017-01/06门诊就诊的角膜正常的白内障患者41例64眼,术前分别采用IOL Master和Pentacam测量角膜屈光力,采集的数据包括：sim K、true net power、角膜中央1.0～7.0mm直径Holladay equivalent K(EKR)(Pentacam)及Km\〖Km=(K1+K2)/2\〗(IOL Master)。两种仪器测量K值之间的差异采用配对样本t检验,其相关性采用Pearson相关性分析,一致性采用Bland-Altman法。

结果：角膜正常的白内障患者Pentacam测量所得true net power、角膜中央1.0、2.0、3.0mm直径EKR 比IOL Master测量所得Km小; 角膜中央4.5、5.0、6.0、7.0mm直径EKR比IOL Master 测量所得Km大,差异具有统计学意义(均P<0.01)。Pentacam测量所得 sim K、角膜中央4.0mm直径EKR与IOL Master测量所得Km差值最小,差值均值分别为-0.03±0.252和0.04±0.244D,差异无统计学意义(t=-1.018,P=0.313; t=1.461,P=0.149); 且一致性最高,95%一致性界限分别为-0.53～0.46D和-0.43～0.52D。两种仪器间所测量K值均具有较高的相关性(均r>0.9,P<0.01)。

结论：角膜正常的白内障患者Pentacam测量所得sim K、角膜中央4.0mm 直径EKR与IOL Master测量所得Km一致性最高,但使用中需结合临床意义进一步对仪器的适用范围加以判断。     

四种不同仪器测量白内障患者术前角膜曲率和散光的比较

目的：比较波前像差仪OPD-Scan Ⅲ、光学相干生物测量仪IOL Master、三维眼前节分析系统Pentacam及自动电脑验光仪KR-8900 四种不同仪器测量角膜曲率、角膜散光的差异性和一致性，指导白内障术前检查应用。

方法：前瞻性临床研究。选取2017-04/06在我院就诊的白内障患者45例86眼，分别应用OPD-Scan Ⅲ与Pentacam、IOL Master、KR-8900测量患者受检眼角膜曲率(K₁、K₂)和散光轴位，并计算出平均角膜曲率(mean keratometry，K_m)、散光矢量J₀和J₄₅，采用配对样本t检验对测量结果的差异进行比较，相关性分析采用线性相关分析，一致性评价采用Bland-Altman分析。

结果：在测量K₁值时，OPD-Scan Ⅲ与IOL Master测量值的差异有统计学意义(P<0.001)； 在测量K₂、K_m值时，OPD-Scan Ⅲ与IOL Master、Pentacam测量值的差异均有统计学意义(P<0.05)； OPD-Scan Ⅲ与另外3种仪器的其他测量值间相比较，差异无统计学意义(P>0.05)。经Pearson相关分析，其结果显示：OPD-Scan Ⅲ与KR-8900、IOL Master及Pentacam测量值间均有一定相关性(r=0.408～0.980，P<0.001)。Bland-Altman散点图中，OPD-Scan Ⅲ与Pentacam及IOL Master在测量角膜曲率时一致性较差，与KR-8900的一致性较好； OPD-Scan Ⅲ与KR-8900、IOL Master、Pentacam在测量角膜散光时一致性较差。

结论：OPD-Scan Ⅲ具有操作简单方便、非接触式等优点。测量角膜曲率时，OPD-Scan Ⅲ与KR-8900一致性较好，可以相互替换，与Pentacam及IOL Master一致性较差； 测量角膜散光时，OPD-Scan Ⅲ与KR-8900、IOL Master及Pentacam一致性较差，使用时需根据4种仪器的原理、适用范围及临床情况加以衡量。     

Pentacam和Keratron Scout测量Kappa角的一致性分析

目的：探讨Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量Kappa角的一致性,评价两种仪器测量结果的重复性。

方法：前瞻性随机对照研究。选取2018-01-01/30在我院眼视光中心行近视术前检查的患者69例,所有受试者由同一检查者分别采用Pentacam和Keratron Scout重复测量3次,以(X,Y)坐标形式记录Kappa角的大小,采用组内相关系数(ICC)、Cronbach''s Alpha系数评价两种仪器测量Kappa角的重复性; t检验比较两种仪器测量结果的差异,Pearson相关分析其相关性; Bland-Altman图评估两种仪器测量结果的一致性。

结果：3次重复测量时,两种仪器均表现出很好的重复性,两种仪器测得Kappa角差异无统计学意义(X值：P=0.17; Y值：P=0.61),Pearson相关分析表明Kappa角大小具有相关性(X值：r=0.90,P<0.01; Y值：r=0.91,P<0.01)。Bland-Altman图显示X值和Y值95%一致性区间分别为-0.11～0.14mm和-0.10～0.11mm。

结论：Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量角膜屈光手术患者Kappa角重复性好,两种仪器测量的Kappa角结果一致性好,可以相互验证。     

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.     

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.     

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.     

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.     

Nutritional antioxidants and age-related cataract and maculopathy

Loss of vision is the second greatest, next to death, fear among the elderly. Age-related cataract (ARC) and maculopathy (ARM) are two major causes of blindness worldwide. There are several important reasons to study relationships between risk for ARC/ARM and nutrition: (1) because it is likely that the same nutritional practices that are associated with prolonged eye function will also be associated with delayed age-related compromises to other organs, and perhaps, aging in general, (2) surgical resources are insufficient to provide economic and safe surgeries for cataract and do not provide a cure for ARM, and (3) there will be considerable financial savings and improvements in quality of life if health rather than old age is extended, particularly given the rapidly growing elderly segment of our population. It is clear that oxidative stress is associated with compromises to the lens and retina. Recent literature indicates that antioxidants may ameliorate the risk for ARC and ARM. Given the association between oxidative damage and age-related eye debilities, it is not surprising that over 70 studies have attempted to relate antioxidant intake to risk for ARC and ARM. This article will review epidemiological literature about ARC and ARM with emphasis on roles for vitamins C and E and carotenoids. Since glycation and glycoxidation are major molecular insults which involve an oxidative stress component, we also review new literature that relates dietary carbohydrate intake to risk for ARC and ARM. To evaluate dietary effects as a whole, several studies have tried to relate dietary patterns to risk for ARC. We will also give some attention to this emerging research. While data from the observational studies generally support a protective role for antioxidants in foods or supplements, results from intervention trials are less encouraging with respect to limiting risk for ARC/ARM prevalence or progress through antioxidant supplementations, or maintaining higher levels of antioxidants either in diet or blood. Without more information it is difficult to parse these results. It would be worthwhile to determine why the various types of studies are not yielding similar results. However, there are many common insults and mechanistic compromises that are associated with aging, and proper nutrition early in life may address some of these compromises and provide for extended youthful function later in life. Indeed, proper nutrition, possibly including use of antioxidant supplements for the nutritionally impoverished, along with healthy life styles may provide the least costly and most practical means to delay ARC and ARM. Further studies should be devoted to identifying the most effective strategy to prevent or delay the development and progress of ARC/ARM. The efforts should include identifying the right nutrient(s), defining useful levels of the nutrient(s), and determining the age when the supplementation should begin.     

Ethics and optometry: concepts and applications

Ethics refers both to the study of behaviour, and moral principals. The related concepts of justice and law are also relevant to optometry. A profession typically claims specialist knowledge and ethical behaviour – putting the interests of clients above its own. However, professional codes fail as ethical directives, and their goals are questioned. Beginning with broad principles, institutional ethics and issues of general health care provision are considered, and applications to optometry are made. Ethical theory can guide us in interacting with our patients, utilising resources and ordering priorities. The conservative approach to consumerism and advertising is defended on the basis of protecting public and professional interests. Ethical behaviour can be fostered, and this process should begin in undergraduate education.     

Exogenous attention and color perception: performance and appearance of saturation and hue

Exogenous covert attention is an automatic, transient form of attention that can be triggered by sudden changes in the periphery. Here we test for the effects of attention on color perception. We used the methodology developed by Carrasco, Ling, and Read [Carrasco, M., Ling, S., & Read, S. (2004). Attention alters appearance. Nature Neuroscience, 7 (3) 308-313] to explore the effects of exogenous attention on appearance of saturation (Experiment 1) and of hue (Experiment 2). We also tested orientation discrimination performance for single stimuli defined by saturation or hue (Experiment 3). The results indicate that attention increases apparent saturation, but does not change apparent hue, notwithstanding the fact that it improves orientation discrimination for both saturation and hue stimuli.     

Aberration and contrast sensitivity comparison of aspherical and monofocal and multifocal intraocular lens eyes

BACKGROUND: Higher-order aberrations and contrast sensitivity were evaluated in patients who underwent phacoemulsification cataract extraction followed by implantation of aspherical, monofocal or multifocal intraocular lens (IOL) replacements. METHODS: In this comparative trial, 124 patients with an average age of 66.8+/-5.2 years and their 124 eyes were randomly divided into three surgical implantation groups to receive one of three types of IOLs in replacement of cataract lenses. The patients of group 1 were given an aspherical IOL Z9001 (AMO, Santa Ana, CA, USA) replacement, and group 2 was implanted a monofocal IOL SA60AT (Alcon, Fort Worth, TX, USA) and group 3 the multifocal IOL SA40N (AMO). Post-surgical best-corrected visual acuity, corneal aberrations, total ocular aberrations, pupil diameters, capsulorhexsis sizes and contrast sensitivity were measured and compared. RESULTS: There was no statistical difference for mean best-corrected visual acuity, pupil diameter, curvilinear capsulorhexis size and corneal aberration among the three groups. For the spherical aberration, fourth-order higher-order aberration and total ocular higher-order aberration, the SA40N group was higher than the SA60AT group and the SA60AT group was higher than the Z9001 group, and the differences between the three groups were statistically significant for these measurements. Contrast sensitivity was higher for the Z9001 group than the SA60AT group and the SA60AT group was higher than the SA40N group, and the difference was statistically significant in all the spatial frequencies of 3, 6, 12 and 18. CONCLUSIONS: Although the multifocal IOL can provide near vision, it can increase higher-order aberration and negatively influence contrast sensitivity. However, the aspherical IOL can reduce aberration and improve contrast sensitivity as compared with the monofocal IOL.