Growth spurt in a lens with a posterior subcapsular cataract

Over a period of 5 years, the lenses of a patient with a unilateral posterior subcapsular cataract were documented using Scheimpflug slit-image photography. For the first time ever, a growth spurt was observed of the cataractous lens. It is postulated that this could be a reflection of either a mitotic spurt of the lens epithelium or a failure of compaction of the the deeper lens fibres.     

数字化图像分析在眼整形手术中的应用

客观、准确地测量眼睑位置可用于辅助眼整形手术术前诊断、医疗记录、评估手术疗效和教学、研究等方面.基于数字化图像的测量较临床手工测量更具优势,标准化的数字化图像为数据测量及图像处理提供了一种可重复性和可靠性更高的方法.规范化的相机位置、摄像参数、照明条件、背景及患者呈现状态可以提高照片质量.对常用数据的传统测量方法(手动...     

人和动物眼前段的Scheimpflug照相及计算机图像分析

目的 应用Ｓｃｈｅｉｍｐｆｌｕｇ照相技术在活体内对人眼和几种动物眼的眼前部图像进行测量分析。方法 应用眼前部图像分析系统（ＥＡＳ－１０００,日本Ｎｉｄｅｋ）,对正常成人以及豚鼠、大鼠、兔和 眼前部照相并作图像分析。结果 用ＥＡＳ－１０００系统能在人眼、豚鼠和大姒眼得到清晰的眼前部图像,而在兔和猫眼仅得到前半部晶状体以前的图像。测量并比较分析了各种眼球的角膜及晶状体的多个生理参数。结论 Ｓｃｈｅｉｍ     

The clinical grading of lens opacities

A simple system has been developed for the clinical grading of the presence and severity of lens opacities. The densities of nuclear opacities as seen on clinical slit-lamp examination are graded in comparison with a set of standard photographs. The extent of cortical opacities seen on retroillumination is estimated in terms of segments involved. The dimensions of posterior subcapsular opacities are measured using the slit beam. Inter-and intra-observer trials were conducted with three observers. Twenty subjects were selected to provide a range of lens opacities. Weighted Kappa statistics for intraobserver agreement for these three types of opacities range between 0.58 and 1.00 and for intraobserver agreement between 0.41 and 0.71. This clinical grading system shows good reproducibility and compares well with the grading of lens opacities in photographs. It should prove to be of considerable use in clinical and epidemiological studies of cataract.     

Monitoring in vivo lens changes

In this study the AA attempted to evaluate the relationship between lens optical density and lens fluorescence determined in vivo, with some specific (in vitro) biochemical changes occurring during cataract development. Special attention has been given to the comparison between diabetic and non diabetic cataracts. Prior to surgery all lenses were analysed by Scheimpflug photography to evaluate the topography of opacities and fluorescence distribution. Individual lenses were separated into cortex and nucleus and the amount of high molecular weight (HMW) protein aggregates was determined by FPLC (Fast Performance Liquid Chromatography). The results found in this study have shown that, as it would be expected, diabetic cataractous lenses present higher fluorescence levels than senile cataracts. It has also been shown that the increase in lens optical density, determined by Scheimpflug photography is clearly related to the increase in the amount of HMW-aggregates. Furthermore, in diabetic cataracts, a good correlation between protein aggregation and lens fluorescence determined in vivo has been found. Thus, it seems that in diabetic cataracts chemical or metabolic mechanisms leading to the production of fluorescent chromophores may be related to protein aggregation and therefore to the major processes involved in cataract development.     

免散瞳眼底数码照相机筛查白内障需手术者的方法评估

目的通过免散瞳眼底数码照相方法诊断白内障并筛出白内障需手术者,探讨用该方法筛查白内障的可行性。设计前瞻性病例系列。研究对象2009年2月至8月同仁医院白内障中心就诊的白内障患者92例165眼。方法所有病例均检查裸眼视力及矫正视力,经裂隙灯显微镜检查并进行白内障分类分级。使用免散瞳眼底数码照相机进行小瞳孔眼底数码照相检查,根据眼底照片的模糊程度作出分级诊断。比较免散瞳眼底照相的诊断结果与裂隙灯检查结果的一致性,两种手术诊断标准所得筛查结果进行Kappa检验。主要指标灵敏度、特异度、约登（Youden）指数、阳性预测值、阴性预测值。结果免散瞳眼底照相与裂隙灯检查结果呈高度一致性。以裂隙灯显微镜检查为金标准,各级白内障中2级以上者免散瞳眼底照相诊断的灵敏度均在89％以上。免散瞳艰底照相筛查白内障需手术者的Kappa值均达0．70以上。皮质性、核性和囊下性的阳性预测值分别为100％、84．2％和76．2％,阴性预测值分别为82．4％、93．3％和91．9％。结论用免散瞳眼底照相方法筛查明显影响视力的中、重度白内障是可行的。可以用免散瞳眼底照相方法替代裂隙灯显微镜检查法筛查白内障需手术者。     

Photography of the anterior eye segment according to Scheimpflug's principle: options and limitations – a review

Scheimpflug photography and densitometric image analysis are very precise techniques for light scattering measurement and biometry in the anterior segment of the eye. They provide reproducible data on the characteristics of the anterior eye segment in clinical and experimental studies and the set of data obtained allows discrimination of light scattering changes because of ageing, disease or toxic effects. The techniques can also be used to determine no-effect levels or maximally tolerable dosages of physical and chemical noxious factors. Several Scheimpflug cameras have been marketed, but the only cameras commercially available today are the Nidek EAS 1000 and the Oculus Pentacam. This review outlines the development of the technique and its introduction into ophthalmology. Furthermore, the application of the technique in clinical and experimental ophthalmology as well as in ocular toxicology are presented and discussed.     

Pentacam眼前节分析仪定量测定晶状体密度及厚度

目的定量分析不同年龄及屈光度人群的晶状体密度及厚度。探讨晶状体与年龄及屈光度的关系。方法收集2006年5月至12月在复旦大学附属眼耳鼻喉科医院视光部就诊者，其中无白内障者262例（262眼），白内障患者38例（38眼）。美多丽点眼30min后进行裂隙灯生物显微镜、综合验光和0CULUS Pentacam眼前节分析仪的检查。Pentacam检查采用Enhanced dynamic的扫描模式，记录经角膜顶点轴线上晶状体各层，包括前囊、前囊下皮质、前皮质、核（最低点）、核（最高点）、后皮质及后囊的密度值，并手动测量该轴线上的晶状体厚度值。分析晶状体密度和厚度与年龄及等效屈光度的关系，并比较白内障晶状体与透明晶状体形态的差异。结果除前囊下皮质以及后囊外，晶状体各层的密度值均与年龄呈正相关关系，其中又以晶状体前皮质以及晶状体核密度与年龄的关系最为密切。可获得晶状体密度（Y）与年龄（X）的回归方程分别为：Y前皮质=5.96＋0.18X；Y柱最低=6.09＋0.07X；Y柱最高=6.81＋0.08X。晶状体厚度（Y）与年龄（X1）和屈光度（X2）均相关，可获得回归方程：Y厚度=3244.79＋17.38X1＋20.07X2。结论晶状体密度与厚度均随年龄呈递增趋势。可根据每个患者的年龄及屈光度进行估算，结果可用于白内障的筛查及辅助近视眼手术方式的选择。     

Photographic investigation of the human lens and cataract

Slit-image photography of the anterior segment of the eye can provide important information about the dimensions and optical densities of the refractive structures. It is crucial that the slit-image photograph be in perfect focus and that the slit-beam cut in exactly the same section (along the optic axis) on each occasion. The equipment, principles and techniques which make such precision slit-image photography possible are discussed. Clinical and research applications, especially regarding the human lens and cataract, are summarized.     

Early cortical lens opacities: a short overview

Cataract is still the dominant cause of blindness worldwide. Cortical cataract is the most prevalent of the age‐related changes in the human lenses that require surgical intervention to restore vision. The absence of adequate cataract surgery in most developing countries is the main cause of the high prevalence of cataract blindness worldwide. Lens ageing is accompanied by dramatic increases in stiffness, light scattering and coloration of the lens nucleus. These changes start to become manifest as early as the fourth or fifth decade of life and lead to nuclear cataract in old age. In the same period the equatorial deep lens cortex starts to show small opaque shades, which eventually grow out to segmental and annular opacities. These opaque shades are filled with small vesicles and contain abnormal amounts of cross‐linked proteins, cholesterol and phospholipids. They are bordered by membranes that are rich in square arrays, have ‘degenerate’ gap junctions and have few intramembranous particles. It has been shown that the opaque shades represent cohorts of locally affected fibres segregated from unaffected neighbouring fibres by ‘non‐leaky’ membranes. This segregation is an effective mechanism delaying the outgrowth of these opacities to cuneiform cataracts entering the pupillary space and thus leading to blinding cortical cataracts. Although cataract formation is mostly considered to be a multi‐factorial disease, oxidative stress might be one of the leading causes for both nuclear and cortical cataract. In cortical cataracts shear stress between cortex and nucleus during accommodation may also play a significant role.     

Changes in the lens epithelium with respect to cataractogenesis—light microscopic and Scheimpflug densitometric analysis of the cataractous and the clear lens of diabetics and non-diabetics

Background We compared the human lens documented, using the Scheimpflug densitometry, with the light microscopic changes in the epithelium of the anterior central lens in patients with age-related cataract and diabetes mellitus type II and verified the findings on the control tissue of the clear eye lens. We wanted to determine the relevance of the lens epithelium in cataract formation in type II diabetics compared to non-diabetics.Materials and methods One hundred fifty central lens capsules (138 cataract and 12 clear lenses) of type II diabetics (n=77, 45 female, 32 male) and non-diabetics (n=73, 41 female, 32 male) were examined by light microscope, regarding defined histomorphological parameters. Further criteria were duration of diabetes, diabetic retinopathy, cataract (PENTACAM, scheimpflug densitometric definition), protein content in the aqueous humour (laser flare meter 500 KOWA, tyndallometry), different blood parameters and glucose content in the aqueous humour.Results The mean cell density in the cataractous lens in type II diabetics was 3,951±528 cells/mm² and in non-diabetics 4,329±580 cells/mm² (P<0.001); in the clear lens it corresponded to 4,593±409 cells/mm² (type II diabetics) and 4,894±333 cells/mm² (non-diabetics, P=0.207). The cell density of the cataractous lens in type II diabetics (P=0.005) and in non-diabetics (P=0.035) is smaller than that of the clear lens. The cell area of the lens epithelium in the cataractous diabetic lens is larger (P<0.001) and the nucleus-plasma ratio is lower (P<0.001) than those of the clear non-diabetic lens. The increase in damage of the lens epithelium correlates with the decrease of cell density (P< 0.001), the increase of nucleus area and volume (P< 0.001), and the decrease of nucleus-plasma ratio (P< 0.001). Risk factors for the decrease of cell density are advanced age (P=0.015), type II diabetes (P=0.01), increase in glucose content in the aqueous humour (P=0.014), increase in blood sugar (P=0.003) and increase in glycosylated haemoglobin (P=0.039).Conclusions The lens epithelium is primarily damaged in type II diabetics who develop age-related cataract. This might play an important role in cataract formation.     

Changes in the internal structure of the human crystalline lens with age and accommodation

Scheimpflug images were made of the unaccommodated and accommodated right eye of 102 subjects ranging in age between 16 and 65 years. In contrast with earlier Scheimpflug studies, the images were corrected for distortion due to the geometry of the Scheimpflug camera and the refraction of the cornea and the lens itself. The different nuclear and cortical layers of the human crystalline lens were determined using densitometry and it was investigated how the thickness of these layers change with age and accommodation. The results show that, with age, the increase in thickness of the cortex is approximately 7 times greater than that of the nucleus. The increase in thickness of the anterior cortex was found to be 1.5 times greater than that of the posterior cortex. It was also found that specific parts of the cortex, known as C1 and C3, showed no significant change in thickness with age, and that the thickening of the cortex is entirely due to the increase in thickness of the C2 zone. With age, the distance between the sulcus (centre of the nucleus) and the cornea does not change. With accommodation, the nucleus becomes thicker, but the thickness of the cortex remains constant.     

Separation of lens proteins in rats with tryptophan deficiency cataracts

Rats on tryptophan-free diet develop posterior subcapsular (saucershaped) cataracts and discrete anterior subcapsular haze. Trp-deficient rats have a lower lens dry weight than normal lenses of the same age. There is a slight significant increase of lens water in the diet group. The water insoluble lens protein showed no changes by the trp-free diet, whereas β-crystallins were severely affected. After 20 days of trp deficiency the amount of β-crystallin was only 72% of the value found in controls. α- and γ-crystallins were less affected and showed only a slight (but significant for α-crystallin) decrease.     

A co-occurrence of familial isolated cherry red spot and multiple lens opacities

Purpose

To present a co-occurrence of familial isolated cherry red spot (CRS) and multiple lens opacities in all siblings from the same family without any other systemic or ocular diseases.

Methods

Four siblings from the same family had bilateral punctate lens opacities and bilateral CRS at the macula.

Results

The oldest one had left eye exotropia and amblyopia, otherwise the other siblings had no additional ocular findings. Systemic investigation, physical examination, and laboratory tests were within normal limits.

Conclusion

Bilateral isolated CRS along with punctate lens opacities were seen in all siblings from the same family without any systemic and ocular diseases.     

Role of Scheimpflug imaging for assessment of posterior lens capsule in pediatric traumatic cataract

Purpose:To find the accuracy of Scheimpflug imaging for the evaluation of posterior lens capsule and to assess the incidence of pre-existing posterior capsular tear (PCT) in pediatric traumatic cataracts.Methods:It was a prospective, non-randomized, and interventional study. Scheimpflug imaging was done preoperatively to detect pre-existing PCT in pediatric traumatic cataracts after blunt trauma. All patients underwent cataract extraction with intraocular lens implantation. Intraoperatively, the posterior capsule status was noted and compared with the preoperative Scheimpflug images.Results:Forty-seven eyes of 47 children having traumatic cataracts following closed-globe injury were included. There were 32 males and 15 females with a mean age of 10.91 ± 2.75 years. The mean duration of performing the Scheimpflug imaging from injury was 41.7 ± 7.78 days. Preoperative Scheimpflug imaging showed intact posterior lens capsule in 36 eyes and PCT in 11 eyes. Intraoperative, 37 eyes had an intact posterior lens capsule and 10 eyes had PCT. The Scheimpflug imaging did not detect the PCT in three eyes (false-negative), and in four eyes, PCT was detected falsely on Scheimpflug imaging (false-positive). The sensitivity and specificity of the Scheimpflug imaging were 70 and 89.18%, respectively. The accuracy of the technique was 85.11%.Conclusion:Scheimpflug imaging is a useful modality for the detection of PCT preoperatively in cases with doubtful posterior lens capsule integrity.     

北京农村居民白内障筛查流程的探讨

目的通过免散瞳数码眼底照相在农村居民白内障筛查的应用,探讨农村白内障筛查流程的可行性。设计人群横断面研究。研究对象北京农村参加合作医疗的55～80岁居民约52万人。方法2008年7-11月对北京10个涉农区县进行了以白内障为主的眼病筛查。由各区县卫生局组织,在视力检查和慢性病问卷调查后,对低视力（生活视力）者应用免散瞳数码眼底照相机进行跟前节和眼底照相,图像上传到浏览器,服务器（B／S）构架的数据库,由专业人员集中阅片,并做出白内障、需白内障手术和其他眼病的诊断。主要指标低视力及需白内障手术者的人数。结果目标人群中建立眼科电子病历43．5万份（应答率83．6％）。发现低视力患者约4．6万人,行眼前节及眼底照相21383人。发现白内障患者12441人,占照相者的58．14％。需手术的白内障患者4623人,占照相者的21．60％。除白内障以外,还发现了其他眼科疾病,并得到了慢性病的资料。结论50岁以上农村居民在低视力筛查后,以数码眼底照相机免散瞳眼前节和眼底照相筛查白内障的流程不仅具有简单、快速的优点,且可实现多种致盲跟病联合筛查。（眼科,2009,18：80—83）