先天性白内障术后眼轴角膜曲率及屈光度变化

目的 探讨先天性白内障术后患儿眼轴、角膜曲率及屈光度的变化.方法 对49例（84只眼）先天性白内障行晶状体超声乳化手术联合后囊切除及前部玻璃体切除手术,按年龄分为＜3岁、3～5岁及＞5岁3组.术前及术后1年分别测量眼轴长度、角膜曲率;手术后1周及术后1年验光.结果 3组患儿眼轴长度增长量分别为（1.88±0.93） mm,（1.37±0.78） mm及（0.54±0.82） mm,术后眼轴长度变化量随年龄增长而下降,3组间眼轴增长的长度比较差异有统计学意义.3组角膜曲率变化量分别为（-0.12 ±0.08）D,（＋0.09±0.05）D及（-0.06 ±0.02）D.角膜曲率术前和术后1年变化量3组间比较,差异无统计学意义.术后1周到1年屈光度的变化量分别是-2.06 D,-0.42 D和-0.23 D.3组屈光度数均有向近视方向转移的趋势,但随年龄增大,转移趋势变慢.结论 先天性白内障患儿施行白内障摘出合并前部玻璃体切除Ⅰ期人工晶状体植入术,对患儿眼球的发育无明显影响.儿童植入人工晶状体的屈光度选择应该考虑到儿童的年龄及眼轴的变化的影响.     

儿童双眼先天性白内障人工晶状体植入术后眼轴长度和屈光状态的变化

目的　探讨儿童双眼先天性白内障摘除人工晶状体植入术后眼轴长度和屈光状态的变化情况。方法　对38例(76只眼)已行白内障摘除、前后环形撕囊、前段玻璃体切除、晶状体囊袋内人工晶状体植入术的双眼先天性白内障患儿进行回顾性研究。按手术年龄分为2 ~3岁(A组)、4~5岁(B组)、6~7岁(C组)、8~12岁(D组)4组,检测术前和术后5年术眼的眼轴长度和角膜屈光力、术后1个月和5年的屈光状态,分析视力预后与眼轴长度和屈光状态变化的关系。结果　4组平均屈光度数变化分别为-2. 06、-1 .81、-0 .56及-0. 25D,差异有统计学意义(P<0. 01);眼轴长度平均增长1. 21、1 .13、0. 47及0 .34mm,差异有统计学意义(P<0 .01)。各组手术前、后角膜屈光力比较,差异均无统计学意义(P>0. 05)。术后50只眼( 65. 8% )最佳矫正视力≥0 .5。术后最佳矫正视力与屈光度数变化和眼轴长度变化无相关性(P>0. 05)。结论　双眼白内障摘除、前段玻璃体切除、晶状体囊袋内人工晶状体植入术可安全、有效治疗儿童双眼先天性白内障;术后屈光状态出现向近视方向移动的趋势,眼轴长度接近同龄正常儿童,屈光度数和眼轴长度的变化随手术年龄的增大而趋于稳定。2~5岁患儿双眼人工晶状体度数的选择应以低度欠矫为宜。     

人工晶状体植入术治疗儿童白内障临床效果及影响因素

目的:探讨先天性白内障人工晶状体(intraocular lens,IOL)植入术后屈光状态的远期变化及其相关影响因素。方法:入选我院2013-01/2014-01先天性白内障患儿70例110眼,按患者年龄分为A组(<2岁)、B组(2~6岁)、C组(7~12岁),均进行先天性白内障摘除联合IOL植入术,比较三组术后角膜曲率、眼轴、屈光状态情况,分析其眼轴变化影响因素。结果:A组、B组、C组术后角膜曲率差异无统计学意义(P>0.05);A组术后与术后3mo角膜曲率比较差异均有统计学意义(P<0.05),B和C组术后与术后3mo角膜曲率差异无统计学意义(P>0.05);A组术后3mo角膜曲率差异显著高于B组和C组(P<0.05),B组和C组术后3mo角膜曲率差异无统计学意义(P>0.05);A组、B组和C组术后眼轴长度差异无统计学意义(P>0.05);A组术后与术后3mo眼轴长度比较差异均有统计学意义(P<0.05),B和C组术后与术后3mo眼轴长度差异无统计学意义(P>0.05);A组术后3mo眼轴长度差异显著高于B组和C组(P<0.05),B组和C组术后3mo眼轴长度差异无统计学意义(P>0.05);三组患者术后屈光状态呈现近视移动变化趋势,A组术后屈光变化率及屈光度变化显著高于B和C组,差异有统计学意义(P<0.05)。结论:先天性白内障摘除联合IOL植入术后屈光状态呈现近视化趋势,2岁以下患儿表现显著。近视化影响因素主要为眼轴增长。     

IOL Master测量人工晶状体度数精确性的临床评价

目的：：比较IOL Master与传统超声生物测量法对人工晶状体度数测量的准确性和特点,评价IOL Master的临床应用价值。方法：分析2014-06/2015-06间于我院行白内障超声乳化摘除及人工晶状体植入术的年龄相关性白内障患者164例206眼,术前分别用IOL Master、传统的超声生物测量仪和角膜曲率计测量眼轴长度和角膜曲率,使用SRK-Ⅱ公式计算人工晶状体度数。对患者施行超声乳化白内障摘除术后,按照IOL Master测量得出的人工晶状体度数植入可折叠人工晶状体,术后3 mo检查患者的视力和屈光状态。结果：IOL Master 和超声波检查法测得的眼轴分别为23.86±1.05mm和23.50±0.83mm,两者对比差异有统计学意义( P=0.025)。 IOL Master 和手动角膜曲率计测得的角膜曲率分别为44.18±1.35D和43.70±1.41D,两者对比差异有统计学意义(P=0.01)。术后3mo患者平均绝对屈光误差分别为0.41±0.30D 和0.93±1.10D,两者对比差异有统计学意义(P=0.027)。结论：IOL Master具有非接触性、操作简便、安全而且易于被患者接受的特点,对眼轴长度和角膜曲率测量的精确性较高,从而对人工晶状体度数测算更精确,提高了对患者术后屈光状态的可预测性。     

先天性白内障人工晶状体植入术后眼球发育和屈光的变化

严重影响儿童视觉发觉的先天性白内障需要接受手术治疗,通过恢复视轴的清晰,为视觉发育创造条件。手术方式以白内障摘除联合一期或二期人工晶状体植入术为主,患儿年龄是决定手术时机和方式选择的重要因素。由于植入人工晶状体的度数固定,破坏了儿童眼球发育过程中各屈光因素演化的平衡状态,使得术后患儿的眼球发育和屈光状态可能受到诸多手术相关因素及人工晶状体本身的影响,主要体现在眼轴长度变化及近视漂移两方面。（国际眼科纵览,2012,36：327—330）     

先天性白内障儿童眼球发育的观察

目的通过观察眼轴和角膜屈光力,了解先天性白内障儿童的眼球发育状况.方法将64例单眼先天性白内障和107例双眼先天性白内障患儿分为1岁以下、1～3岁、4～5岁、6～9岁、10岁以上5个年龄组比较分析其眼轴和角膜屈光力情况.结果在P＝0.05水平上只有1～3岁组单眼先天性白内障患眼眼轴较健眼有显著性差异;单眼先天性白内障与双眼先天性白内障患眼轴长度无显著性差异;64.4%先天性白内障眼眼轴长于正常同龄儿童均值;单眼先天性白内障患儿的患眼与健眼间角膜屈光力无显著性差异.结论形觉剥夺只是影响先天性白内障眼轴发育的诸多因素之一,为儿童先天性白内障选择人工晶状体屈光度时也应考虑其他因素对眼轴发育的影响.     

先天性白内障摘除人工晶体植入术后屈光状态的观察

目的探讨先天性白内障摘除人工晶体植入的临床疗效。方法对3~14岁先天性白内障摘除联合人工晶体植入108例(175眼),随访3~5年,观察视力、角膜曲率、眼轴长度和屈光度的变化。结果术后5年,单眼患者术眼和健眼平均眼轴长度之间无显著性差异(P>0.05);双眼患者平均眼轴长度与单眼患者健眼之间也无显著性差异(P>0.05)。单眼患者术眼和健眼术后5年屈光状态均向近视漂移,二者之间差异有显著性(P<0.01)。结论儿童先天性白内障摘除人工晶体植入不影响患儿眼球的正常发育,人工晶体的选择原则应结合患儿年龄术后形成屈光欠矫。     

早期先天性白内障摘除及IOL植入术后6~8岁眼轴长度变化

目的：观察生后3mo内行先天性白内障摘除术,并在眼轴发育至21mm时行二期人工晶状体植入术后6~8岁人工晶状体（IOL）眼患儿眼轴长度的变化。 方法：对15例26眼出生后3mo内行白内障摘除联合后囊膜连续环形撕囊及前段玻璃体切割术,并在眼轴发育至21mm（年龄在2周岁左右）时行二期人工晶状体植入术后的患儿进行连续观察。分别在6,7,8岁时测量术眼眼轴长度,另选取年龄和性别相匹配的正常儿童作为对照组,采用横断面病例对照研究比较两组间的差异。 结果：各年龄段术后患儿平均眼轴长度分别为23.75±140,23.88±1.73,23.91±1.55mm,与对应年龄对照组比较,6岁阶段眼轴发育比正常对照组儿童长,差异有统计学意义（P＜0.05),7~8岁阶段与正常对照组无差异（P＞0.05）。 结论：出生后早期行先天性白内障摘除并在2周岁左右行二期人工晶状体植入术后的人工晶状体眼患儿,在6~8岁阶段,6岁时眼轴发育较同龄正常儿童快,但7~8岁时眼轴发育较同龄正常儿童基本相同。     

非洲黑人与中国汉族白内障患者角膜曲率、眼球轴长及人工晶状体度数的差异

目的:观察非洲黑人及中国汉族人角膜曲率、眼球轴长及人工晶状体屈光度的差异。方法:回顾性比较60例非洲肯尼亚及60例中国汉族行白内障手术患者角膜曲率、眼轴长度和人工晶状体屈光度的差异。结果:选取60例非洲病例平均年龄67.6±16.4岁,平均人工晶状体度数22.88±1.84D,平均垂直角膜曲率43.03±0.63D,平均水平角膜曲率42.70±0.8D,平均眼球轴长22.81±0.88mm;60例中国汉族病例平均年龄64.7±11.5岁,平均人工晶状体度数21.55±1.67D,平均垂直角膜曲率44.66±1.73D,平均水平角膜曲率43.75±1.80D,平均眼球轴长23.15±0.86mm。两者之差异均有统计学意义。结论:非洲黑人与中国汉族人的眼轴和角膜曲率存在差异,白内障手术时人工晶状体屈光度范围不同。     

两种角膜曲率测量方法在临床中的应用

目的 比较ORBSCANⅡ和角膜曲率计测量角膜曲率的临床应用效果。方法 应用ORBSCANⅡ和角膜曲率计分别测量110眼角膜曲率，A超测量眼轴长度，并分别代入THEORETIC／T或REGRSSIONⅡ公式，计算所需人工晶状体（IOL）度数。结果 角膜曲率及眼轴长度和10L度数之差异均无统计学意义（P〉0．05）。结论 应用ORBSCANⅡ测量角膜曲率和角膜曲率计有很好的一致性，均能较好地为开展白内障超声乳化人工晶状体植入术服务。     

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.