眼挫伤后前房深度和晶状体厚度变化对屈光状态影响的分析

目的探讨眼挫伤后的前房深度和晶状体厚度的变化对屈光状态的影响。方法收集符合条件、资料完整的33例（33眼）眼挫伤的临床资料进行回顾性分析。分析前房深度、晶状体厚度、屈光度、眼轴长度的变化。结果33眼均有不同程度的近视,平均屈光度为（-1．80±0．16）D;入院时伤眼前房深度变浅,平均深度为（3．16±0．08）mm;晶状体厚度增加,平均厚度为（4。11±0．08）mm,对比健眼前房深度（3．32±0．07）mm、晶状体厚度（3．93±0．07）mm及治疗后前房深度（3．39±0．06）mm、晶状体厚度（3．93±0．05）mm差异均具有统计学意义（P〉0．05）,而健眼与治疗后伤眼的前房深度、晶状体厚度相比差异无统计学意义（P〉0．05）。健眼、入院时伤眼、治疗后伤眼前房深度与晶状体厚度之和的分析,两两比较差异均无统计学意义（P〉0．05）。健眼、人院时伤眼、治疗后伤眼的眼轴长度分别为（23．29±0．14）mm、（23．27±0．16）mm、（23．20±0．15）mm,两两比较差异均无统计学意义（P〉0．05）。结论眼挫伤后的近视改变是由于挫伤导致的前房深度变浅和晶状体厚度增加造成的。经过积极治疗这种近视状态是可以恢复的。     

应用超声生物显微镜对挫伤性近视发病机制的研究

目的应用超声生物显微镜（UBM）并结合普通超声波，初步探讨挫伤性近视的发病机制。方法对51例（66只眼）眼球钝挫伤患者，在急性期和恢复期分别用自动验光仪测量屈光度；A超测量晶状体厚度；UBM测量角膜厚度、前房轴深、小梁睫状突距离（TCPD）、A角、睫状突的高度（T值）；66例正常眼为对照进行分析。结果眼球受钝挫伤后均表现为近视；且急性期晶状体变厚、前房变浅、TCPD缩短、A角变小、T值增大（P〈0．05）；而角膜厚度变化不明显（P〉0．05）。对照组各参数比较无明显差异（P〉0．05）。结论挫伤性近视的发病有诸多因素。除睫状肌痉挛外，前房变浅、晶状体变凸是共同机制；而睫状体肿胀及位置的改变是原发因素；UBM具有重要的临床应用价值。     

成年近视眼患者的屈光状态分析

目的通过统计行准分子激光屈光手术的患者术前检查的各项手术指标数据，分析其屈光状态，从而探讨影响近视度数（等值球镜度数）的因素。方法精确测量674例患者（1282眼）的各项术前指标．用SPSS软件包处理所测数据，进行相关的回归分析。结果674例（1282眼）患者，年龄18～43岁，平均（25．0±5．85）岁；等值球镜-0．50～-24．00D，平均（-6．13±1．38）D。近视等值球镜度数（屈光度）与眼轴长度、晶状体厚度呈正相关（分别为r=0．631、0．078，P均〈0．05）；在中度近视组与平均角膜屈光力呈正相关（r=0．093，P〈0．05），而在低、高度近视组与平均角膜屈光力无明显的相关性；与年龄和前房深度呈负相关（分别为r=一0．236、-0．140，P均〈0．05）；与角膜厚度、眼压无明显的相关性。结论眼轴长度、角膜屈光力、晶状体厚度、前房深度和年龄对近视度数（等值球镜度数）均有一定的影响。[眼科新进展2007；27（2）：129-131]     

近视眼眼轴长度、前房深度及晶状体厚度的测量分析

目的探讨近视屈光度与眼袖长度、前房深度及晶状体厚度之间的关系。方法采用日本产NIDEK-US2520B型超声显像仪对屈光度在-3.00D以上的近视患者163例(312眼)进行眼轴长度、晶状体厚度和前房深度测量。结果随着近视度数的增加,其眼轴长度和前房深度明显增加,而晶状体厚度与眼轴长度的比值则显著降低(P<0.05)。在屈光度相同的各组中,眼轴长度、晶状体厚度和晶状体厚度与眼轴长度比值存在明显的性别差异(P<0.05),而前房深度的性别差异无显著性(P>0.05)。结论近视屈光度的增加可同时伴有眼轴长度、前房深度和晶状体厚度与眼轴长度比值的改变。     

调节对儿童屈光构成因素的影响

目的：通过分析调节对儿童屈光构成因素的影响，探讨调节与屈光不正、特别是与近视眼的关系。方法：检测135例（270只眼）儿童睫状肌麻痹前后的前房深度（AD）、晶状体厚度（LT）、玻璃体腔径（VL）、眼轴长度（AL）的变化以及睫状肌麻痹后的屈光状态。对其中136只眼行睫状肌麻痹前后角膜地形图检查。结果：不论远视眼、正视眼还是近视眼在睫状肌麻痹后胶房加深（P＜0．01），晶状体变薄（P＜0．01），玻璃体腔径缩短（P＜0．01），但远视眼睫状肌麻痹后眼轴增长（P＜0．05），近视眼眼轴缩短（P＜0．01）；远视眼睫状肌麻痹后，以角膜中心点中心，直径为3mm的环平均角膜屈光度（MD3，P＝0．009）和角膜曲率K1（P＜0．05）增加；近视眼睫状肌麻痹后除MD3（P＝0．033）、K1（P＜0．05），K2以及以角膜中心点为中心，直径为5mm,7mm的环平均角膜屈光度（MD5、MD7）均降低（P≤0．01）；角膜垂直径线下方的平均角膜屈光度（LMD）大于上方的平均角膜屈光度（UMD）而水平径线颞侧的平均角膜屈光度（LaMD)大于鼻侧的平均角膜屈光度（MMD）（P＜0．01）。结论：调节对眼的几乎所有屈光构成因素有着显著的影响；它本身不仅是传统意义上的晶状体本身屈光度增加，同时还伴有晶状体的相对前移；角膜的非球面性即便是在同一垂直或水平径线上的屈光分布也是非对称的。     

应用Lenstar 900测量不同程度轴性近视生物参数分析

目的：采用眼光学生物测量仪（ Lenstar 900）测量轴性近视眼部生物参数,并分析参数间的关系。 方法：将近视患者413例826眼按照等效球镜度数进行分为3组：低度近视（〈3.00D,104眼）,中度近视（3.00~6.00D,500眼）,重度近视（〉6.00D,222眼）,采用Lenstar 900对所有眼进行检测,得到角膜中央厚度（ CCT ）、前房深度（ AD）、晶状体厚度（ LT）、眼轴长度（ AL）等参数。各组参数进行方差分析,等效球镜、AL,LT之间相关分析。结果：不同程度轴性近视患者AL（F=206.16,P〈0.01）、AD（F=4.764,P〈0.05）存在差异性,而CCT、LT这两项参数无差异性。 Person相关分析等效球镜（ SE）度数与AL（ r=0.662, P〈0.01）、AD（r=0.095,P〈0.05）呈正相关,与CCT,LT无相关性。 AL与AD（r=0.347, P〈0.01）、CCT（r=0.126, P〈0.01）呈正相关,与LT呈负相关（r=-0.265,P〈0.01）。 LT与AD呈负相关（r=-0.496,P〈0.01）。 结论：近视程度越深, AL 和 AD 越大。等效球镜度数与AD呈正相关。 AL与等效球镜度数、AD、CCT正相关,与LT负相关性。 LT与AD呈负相关。     

人眼调节前后眼球形态的磁共振成像初步研究

目的利用磁共振成像（MRI）探讨人眼调节时的晶状体及相关结构形态变化特点。设计前瞻性研究。研究对象健康志愿者。方法对8例健康志愿者11只正视眼分别在视近状态和视远状态进行MRI检查,对晶状体、前房及眼轴的MRI图像进行测量,调节前后晶状体及相关因素的变化进行配对t检验。主要指标晶状体的厚度、截面积,前房深度及眼轴长度。结果11只正视眼视远时晶状体厚度、截面积、前房深度、眼轴平均为（3．51±0．20）mm、（22．89±1．82）mm^2、（3．54±0．27）mm、（23．91±0．90）mm,视近时平均为（3．73±0．34）mm、（23．17±1．66）mm^2、（3．29±0．32）mm、（23．82±1．07）mm,调节前后晶状体厚度、前房深度有显著性差异（t=3．563、P=0．007;t=4．804、P=0．001）,晶状体截面积、眼轴差异无显著性（t=1．890、P=0．095;t=0．913、P=0．388）,晶状体厚度差、前房深度差差异有显著性（P=0．000）。结论MRI能反映晶状体在调节状态下的形态特点,有望成为研究人眼调节机制的重要方法之一。（眼科,2010,19：97-99）     

晶状体眼前房型人工晶状体植入术矫正高度近视后放大率与视力的关系

目的 探讨有晶状体眼前房型人工晶状体植入术后高度近视患者视网膜成像放大率的变化规律,了解视网膜放大率变化与视力提高量之间的关系。方法 对近视屈光度为-15．13D～29．00D的23例患者（30只眼）行有晶状体眼前房型人工晶状体植人术,手术前后检查最佳矫正视力、屈光度、眼屈光参数（角膜曲率、前房深度、眼轴长度、人工晶状体位置）。根据模型眼理论,应用ZEMAX光学设计软件计算手术前后视网膜成像放大率的变化,分析放大率变化与屈光度、最佳矫正视力（BCVA）、视力提高量之间的关系。结果 术后3个月,28只眼（93％）术后BCVA超过术前,2只眼（7％）术后BCVA等于术前。屈光度与放大率变化成正相关,近视越深放大率变化越大（r=0．996,P〈0．01）;屈光度与手术前后最佳矫正视力均为负相关（r=-0．62,-0．57;P〈0．01）;近视越深,最佳矫正视力越差;放大率变化与视力提高量成正相关（r=0．42,P=0．02）;放大率变化较大,术后视力提高量较多。结论 有晶状体眼前房型人工晶状体植入术后视网膜成像放大率变大是影响术后最佳矫正视力提高的因素之一,视力提高量与放大率变化量有一定的相关性。     

阿托品治疗儿童近视

本研究为随机、双盲及安慰剂对照试验，旨在观察阿托品治疗儿童近视的有效性及安全性。400例6～12岁儿童分成两组，每组200例，左、右眼各100只参与治疗。两组间无年龄、性别及种族差异，屈光度数-1．00～6．00D。阿托品治疗组平均近视为（-3．36±1．38）D，安慰剂组平均近视为（-3．58±1．17）D，两组治疗眼眼轴平均长度24．80mm。两组未治疗眼平均近视分别为（-3．40±1．35）D和（-3．55±1．21）D，平均眼轴长分别为24．81和24．76mm。治疗组予1％阿托品，对照组予安慰剂每晚1次（安慰剂含0．5％羟丙基甲基纤维素和1：10000苯扎氯胺）持续2年。研究期间，所有儿童行睫状肌麻痹后自动验光以及全面的眼球生物学测量（包括前房深度、晶状体厚度、玻璃体腔深度和眼轴长。眼轴长平均测6次，离散值〈0．12mm）。近视进展定义为相对于基线值而变化的等效球面量（SER），基线值于初次治疗后2周测定。近视进展的分析包括三部分：M（球镜度数）、J0（0度线上的Jackson交叉柱镜度数）、J45（45度线上的Jackson交叉柱镜度数）。用最佳矫正视力，眼压，裂隙灯、眼底检查及多焦视网膜电图评价安全性。     

巩膜环扎加压术对眼屈光状态影响的临床观察

目的 通过测定巩膜环扎加压术前后眼屈光状态，探讨手术对屈光状态改变的影响。方法 观察行巩膜环扎加压术者19例（19只眼），测定术前1天、术后1月的模拟角膜镜读数、散光度及其轴向、角膜中央区3mm平均屈光力、角膜后表面高度、前房深度、晶状体厚度、眼轴长度、屈光度及术后双眼波前像差。结果 术后术眼各项高阶像差Z3、Z4、Z5及总高阶像差Zg与健眼比较均值增加，其中Z3、Z5及总高阶像差Zg的比较有统计学显著性差异（P〈0．05），K1值、散光值、屈光度、眼轴、前房深度、晶状体厚度及角膜后面表高度比较有显著性差异（P〈0．05），而K2值、散光轴向和角膜中央3mm平均屈光力无显著性差异（P〉0．05）；眼屈光度与眼轴、K1值密切相关，统计学有显著意义；结论 巩膜环扎加压术后，高阶像差增加，低阶像差向负值偏移，柱镜部分增加明显。     

OCT测量近视眼在不同调节状态下眼前段结构变化

目的:探讨不同程度近视眼在不同调节状态下OCT(optic coherence tomography,OCT)测量的眼前段结构的变化。方法:招募60例近视患者,年龄:18～39岁,按近视程度分为轻中度近视组和高度近视组,用眼前段OCT对测试眼分别在调节放松(0D)、诱发3.00D和5.00D调节三种调节状态下进行眼前段扫描分析,分别测量不同调节状态下角膜后表面曲率(posterior corneal curvature,PCC)、前房深度(anterior chamber depth,ACD)、晶状体厚度(lens thickness,LT)和暗瞳直径的大小,采用重复测量的方差分析比较不同调节状态下上述参数的差异以及不同程度近视在相同调节状态下各参数的差异。结果:在调节放松情况下,轻中度近视组眼前段OCT测得的平均PCC,ACD,LT和瞳孔直径(pupil diameter,PD)分别为:6.92±0.91mm,2.67±0.19mm,4.17±0.21mm和6.21±0.56mm;高度近视组的平均PCC,ACD,LT和PD分别为:6.83±0.81mm,2.92±0.23mm,4.22±0.24mm和5.95±0.42mm。轻中度近视组与高度近视组在PCC和LT方面的差异均无显著性(t=0.401,-0.742;P=0.690,0.461),而ACD方面,高度近视组显著大于轻中度近视组(t=-4.637,P=0.000),高度近视组的PD则小于轻中度近视组(t=2.011,P=0.049)。两不同程度近视组中,在0.0D,3.00D和5.00D三种不同的调节状态下测得的PCC的差异均无显著性(F=0.084,0.047;P=0.920,0.954);ACD随调节的逐渐增大而均变浅(F=19.44,8.455;P=0.000,0.001);LT随调节的逐渐增大而均增厚(F=31.149,15.245;P=0.000,0.000);PD随调节的逐渐增大而均减小(F=83.634,53.429;P=0.000,0.000)。结论:眼前段OCT可以定量观察近视眼调节时眼前段各部分的变化,高度近视眼前房较轻中度近视深,而瞳孔较小;发生不同程度调节时,角膜的形状相对稳定,LT,ACD及PD随调节量的增加其变化量逐渐增大。     

Analysis of the eye's anterior segment with optical coherence tomography. Static and dynamic study

PURPOSE: To study the biometric modifications of the anterior segment depending on accommodation and age. To try and define their possible applications in certain fields of anterior segment surgery, in particular in refractive implants. MATERIAL AND METHOD: Anterior chamber biometry can be very easily studied with 1310-nm wavelength optical coherence tomography. The equipment has a fixation target that can be focused and defocused with negative lenses in order to stimulate natural accommodation. The human anterior chamber was therefore studied during accommodation. We studied 104 eyes of 56 patients aged between 7 and 82 years. Refraction was between +5D and - 5D. A single operator carried out all the measurements. The anterior chamber's horizontal diameter, the anterior chamber's depth, the horizontal pupil diameter and the horizontal radius of curvature of the crystalline lens' anterior pole were measured unaccommodated or after stimulating accommodation. RESULTS: The different static or dynamic measurements were compared to ametropia, age and accommodation. At rest, the average AC diameter was 12.33 mm, the average AC depth was 3.11 mm and the average pupil diameter was 4.26 mm. On average, for 1 D of accommodation, the crystalline lens anterior pole moved forward by 30 microm. There was a 0.3-mm reduction in its radius of curvature and a 0.15-mm reduction in pupil diameter. Several other measurements are illustrated on graphs. CONCLUSIONS: The AC OCT is a user-friendly instrument to evaluate the anterior segment and explore the anterior chamber (cornea, iris, crystalline lens, irido-corneal angle). The 1310-nm light wavelength is blocked by pigments preventing exploration behind the iris. However, the AC OCT is capable of providing good-quality images and a better visualization of the anatomical relationships of the anterior segment, even behind an opaque cornea.     

景深对超声乳化术后假晶状体眼伪调节的影响

目的探讨白内障超声乳化术后假晶状体眼的景深对伪调节的影响。方法白内障患者30例（60眼），年龄（62.77±5.27）岁（50-70岁），其中44眼为假晶状体眼。测量屈光状态、调节幅度、瞳孔直径。睫状肌麻痹后，分别在不矫正散光和配戴人工瞳孔镜片（直径2.5mm）情况下测量单眼调节幅度。采用SPSS11.0统计软件行统计学分析。结果假晶状体眼的移近法单眼调节幅度为（2.35±1.14）D。散光和人工瞳孔对调节幅度的影响分别为0.21D和0.16D。调节前、后瞳孔直径分别为（4.52±0.66）mm和（2.72±0.64）mm。单眼调节幅度与调节前后瞳孔直径变化无相关性（r=0.164，P=0.305）。睫状肌麻痹时不矫正散光和配戴人工瞳孔镜片的单眼调节幅度分别为（0.61±0.18）D和（0.77±0.14）D。结论对于白内障超声乳化术后的假晶状体眼，瞳孔和单纯近视散光所致景深是伪调节的产生机制之一，但不是主要机制。增大景深不是改善伪调节的主要方法，今后还需要从人工晶状体本身的设计或在眼内的位置变化等方面来研究伪调节的机制和相应的改善方案。     

角膜塑形镜治疗青少年近视的远期效果

【摘要】 目的 观察角膜塑形镜治疗青少年近视7年的效果。设计 回顾性病例系列。研究对象30例青少年近视患者。方法 对2000-2005年间在北医眼视光学研究中心验配角膜塑形镜且连续配戴7年及以上并可按时复查的30例（60眼）患者,使用综合验光仪、裂隙灯、A超等仪器,分别进行戴镜前及戴镜后6个月,l 、3、5和7年时间点的屈光度、视力、角膜曲率、眼轴长度、前房深度、晶状体厚度等检查的比较,综合各指标评估青少年长期配戴角膜塑形镜的有效性。主要指标 球/柱镜度数、裸眼视力、矫正视力、平均K 值、眼轴长度、前房深度、晶状体厚度。结果 戴镜6个月时,患者裸眼视力从4.26±0.28提高到4.71± 0.36（P=0.00）,角膜曲率平均K值从（43.66±1.85）D变平坦到（42.41±1.66）D（P=0.00）,球镜屈光度（-4.76±2.20）D明显减小到（-2.06±2.90）D（P=0.00）;戴镜6个月至7年,裸眼视力、球镜度、角膜曲率平均K值分别为4.70、-2.80 D、42.40 D,基本趋于稳定且差异无统计学意义;戴镜前至戴镜7年及以上眼轴长度从（25.59±1.07）mm缓慢增加到（26.28±1.44） mm。结论 科学合理配戴角膜塑形镜7 年的结果显示,其可有效地降低患者近视度,提高患者裸眼视力,控制眼轴增长。（眼科, 2012, 21: 371-374）     

Static and dynamic analysis of the anterior segment with optical coherence tomography

PURPOSE: To study biometric modifications of the anterior segment with accommodation and age and determine possible applications in areas of anterior segment surgery, particularly implantation of refractive lenses. SETTING: Clinique Monticelli, Marseille, France. METHOD: The study comprised subjects between 7 years of age and 82 years of age in whom anterior chamber biometry was evaluated using 1,310 nm wavelength optical coherence tomography (OCT). The equipment has a fixation target that can be focused and defocused with negative lenses to stimulate natural accommodation. All measurements were performed by the same operator. The horizontal diameter of the AC, the anterior chamber depth (ACD), the horizontal pupil diameter, and the horizontal radius of curvature of the crystalline lens' anterior pole were measured in the unaccommodated state and after stimulating accommodation. RESULTS: Fifty-six subjects (104 eyes) were included; the refractions ranged from +5.0 diopters (D) to -5.0 D. The static and dynamic measurements were compared with ametropia, age, and accommodation. At rest, the mean AC diameter was 12.334 mm, the mean ACD was 3.106 mm, and the mean pupil diameter was 4.258 mm. With 1.0 D of accommodation, the anterior pole moved forward by a mean of 30 microm, the radius of curvature decreased 0.3 mm, and the pupil diameter decreased 0.15 mm. CONCLUSIONS: The AC OCT is a user-friendly instrument for evaluating the anterior segment and examining the AC (cornea, iris, crystalline lens, and iridocorneal angle). The 1,310 nm light wavelength is blocked by pigments, preventing examination behind the iris. However, the AC OCT is capable of good image quality and visualization of the anatomical relationships in the anterior segment, even behind an opaque cornea.     

Objective evaluation of the changes in the crystalline lens during accommodation in young and presbyopic populations using Pentacam HR system

AIM: To quantify the changes in the lens profile with accommodation in different age groups. METHODS: The Pentacam HR system was used to obtain the images of the anterior eye segment from 23 young and 15 presbyopic emmetropic subjects in unaccommodated (with an accommodation stimulus of 0.0D) and accommodated (with an accommodation stimulus of 5.0D for the young group and 1.0D for the presbyopic group) states. The phakic crystalline lens shape, including curvature of crystalline lens and central lens thickness (CLT), and the measurements of anterior segment length (ASL), central anterior chamber depth (CACD) were investigated. The anterior chamber volume (ACV) was also measured. RESULTS: The reduction of CACD and ACV were significant in both groups after accommodation stimulus. From the profile of anterior eye segment, a significant decrease in anterior crystalline lens radii of curvature (-2.52mm) and a mean increase in CLT (0.222mm) and ASL (0.108mm) were found in the young group with an accommodation stimulus of 5.0D. However, no statistically significant changes of CLT, ASL, or crystalline lens radii of curvature were found in the presbyopic group. CONCLUSION: Our data showed that the shallowing of anterior chamber during accommodation was caused by the forward bulging of the anterior lens surface, rather than by anterior shifting of lens position in either young or presbyopic subjects.     

青少年屈光不正眼在不同调节状态下晶状体的变化特点

目的:观察青少年远视眼与近视眼在不同调节状态下晶状体参数的动态变化,分析其差异并探讨晶状体变化的特点。方法:随机选取2019-01/10于我院门诊就诊的7～15岁青少年屈光不正患者50例86眼,分为近视组(29例46眼,平均等效球镜度-2.17±1.41D)和远视组(21例40眼,平均等效球镜度1.92±1.49D)。通过光学生物测量仪(IOL Master)测量眼轴长度(AL),通过眼前节光学相干断层扫描分析仪(SS-OCT)观察不同调节状态下(0、-3、-6D)晶状体厚度(LT)、晶状体前表面曲率半径(ALRC)、晶状体后表面曲率半径(PLRC)的动态变化。结果:调节放松状态下(0D),近视组LT显著小于远视组,ALRC与PLRC大于远视组(均P<0.01),且远视组眼轴短于近视组(22.49±1.12mm vs 24.48±0.82mm,P<0.01)。随着调节刺激的增大(-3、-6D),两组LT均显著增厚,ALRC与PLRC均显著减小(均P<0.01)。-3、-6D调节状态下,两组ALRC变化率均高于PLRC变化率(P<0.01),但两组间LT变化率及P...     

Pathogenesis of transient high myopia after blunt eye trauma

OBJECTIVE: To determine the pathogenesis of transient high myopia after blunt eye trauma. DESIGN: Two observational case reports and literature review. METHODS: Refraction was measured in two patients with an autorefractometer in the acute and convalescent stages after a blunt eye injury. The anterior chamber angle, the ciliary body, and the choroid were examined by ultrasound biomicroscopy (UBM) in the acute and convalescent stages. In one patient, the anterior chamber depth, lens thickness, and axial length were measured by A-scan ultrasonography in the acute and convalescent stages. MAIN OUTCOME MEASURES: Comparison of the refraction, anterior chamber depth, lens thickness, axial length, and the UBM-determined appearance of the choroid and ciliary body during the acute stage with the values during the convalescent stages. RESULTS: The first patient showed a myopic shift of -9.75 diopters (D) and an anterior chamber shallowing of 0.94 mm measured 3 days after trauma by an air bag inflation compared with the measurements at the convalescent phase. UBM showed an annular ciliochoroidal effusion with ciliary body edema, anterior rotation of the ciliary processes, and disappearance of the ciliary sulcus. Eleven days after the injury, these UBM findings normalized, and the myopia decreased to -0.75 D, 27 days after trauma. The second patient had a myopic shift of -8.9 D compared with the convalescent phase, immediately after blunt trauma by a firework. Seven days after the injury, UBM revealed a partial cyclodialysis in addition to findings similar to those in the first patient. Ten days after injury, a myopic shift (-4.75 D), anterior chamber shallowing (by 1.1 mm), and thickening of the crystalline lens (by 0.27 mm) were observed compared with the convalescent phase. Associated UBM findings confirmed the anterior shift of the lens-iris diaphragm. Seventeen days after trauma, the UBM findings, including the cyclodialysis, were normalized, and the myopia had decreased to -1.0 D. CONCLUSIONS: Transient high myopia after blunt trauma is caused by anatomic changes in the ciliary body and crystalline lens. The anterior shift of the lens-iris diaphragm caused by ciliochoroidal effusion with ciliary body edema and thickening of the crystalline lens from blunt eye trauma are involved in traumatic high myopia.     

Changes in ocular dimensions and refraction with accommodation

The purpose of this study was to measure the changes in ocular dimensions with accom-modation, with particular reference to the radius of curvature of the posterior surface of the crystalline lens. The increase in power of the eye with accommodation is considered to arise primarily from a decrease in the radius of curvature of the anterior surface of the lens, with the role of the posterior surface somewhat unclear. We measured the axial dimensions (A-Scan ultrasonography), cornea1 radius of curvature (keratometryl, refractive error (auto-refractor) and radii of curvature of the lenticular surfaces (video phakometryl for 11 subjects, mean age 21.2 + 2.6 years, for five levels of ocular accommodation up to 8.00D. At maximum accommodation the mean changes were a decrease in anterior chamber depth of 0.24 mm. an increase in lens thickness of 0.28 mm. a decrease in radius of curvature of the anterior surface of the lens of 4.95 mm and 1.34 mm for the posterior surface. The corres-pondtng increase in power of the lenticular surfaces for an equivalent refractive index of 1.422 for the lens was 5.53 D and 3.10 D for the anterior and posterior surfaces respectively. No significant changes were recorded in axial length or vitreous chamber depth. We conclude that when crystalline lens power is calculated on the basis of an equivalent refractive index, changes in the posterior surface of the lens contribute around one third of the Increase in lens power associated with 8.00 D of ocular accommodation.