抑制巩膜软骨层增生对鸡形觉剥夺性近视的影响

鸡形觉剥夺性近视是一种常用的近视模型，研究发现在鸡剥夺眼巩膜软骨层细胞增殖活跃，细胞外基质合成增多，为了解巩膜软骨层细胞的异常增殖在剥夺性近视中眼轴延长的作用，本实验利用一种能抑制细胞增殖的药物5-Fu于剥夺眼结膜下注射，观察5-Fu对形觉剥夺性近视的影响。     

雏鸡形觉剥夺眼屈光状态、眼轴长度及巩膜形态学改变之间的关系

目的:研究雏鸡形觉剥夺性近视眼及形觉剥夺性近视眼恢复模型的屈光状态和眼轴长度的变化,并观察后极部巩膜的形态学改变,为探讨轴性近视的发病机制打下基础.方法:选用新孵出的普通肉食家鸡25只,采用半透明薄膜眼罩遮盖的方法对左眼进行形觉剥夺14d(形觉剥夺组)或遮盖11d后,去遮盖3d(形觉剥夺恢复组).两组右眼作为对照眼.分别对两实验组进行检影验光及A超测量眼轴长度.达规定时限后处死动物,取出眼球,于眼球中央部做矢状面的纵向切开,行HE染色,光镜下观察巩膜形态学改变,采用 Metamorp 图像分析软件测量巩膜软骨层和纤维层厚度.结果:形觉剥夺组剥夺眼形成了高度近视(-12.1±4.3D),眼轴增长(9.86±0.38mm),与右眼的屈光( 2.7±0.5D)和眼轴(8.71±0.28mm)相比,差异具有显著性(P＜0.01);形觉剥夺恢复3d与剥夺14d相比,屈光度(-5.5±1.2D)减低(P＜0.05),眼轴长度虽无明显变化(P＞0.05),但眼轴增长速度明显减慢(0.003mm/d vs 0.196mm/d),甚至比对侧对照眼的增长速度(0.116mm/d)还要慢.各组前房深度、晶状体厚度无明显变化(P＞0.05).巩膜 HE 染色及厚度测量可见,剥夺眼的软骨巩膜增厚(144.3±4.78 vs 128.5±3.84μm),纤维巩膜变薄(12.1±0.9 vs 26.9±1.7μm),纤维层细胞数目减少,排列紊乱;剥夺恢复眼与剥夺眼相比,软骨层厚度变薄(135.4±3.32 vs 144.3±4.78μm),纤维层厚度增加(20.6±1.2 vs 12.1±0.9μm),分别接近对侧对照眼的软骨层和纤维层厚度.结论:形觉剥夺可导致幼鸡眼轴增长,诱发轴性近视,此眼轴增长主要是眼球后段的增长.在幼鸡发育期间去剥夺后,近视屈光度减低,眼轴增长速度减慢.伴随形觉剥夺性近视的形成,剥夺眼的纤维巩膜变薄,发生退行性改变.     

豚鼠短期形觉剥夺性近视屈光度眼轴及巩膜改变

目的:观察豚鼠短期形觉剥夺性近视(form deprivationmyopia,FDM)眼轴、屈光度变化及后极部巩膜病理性改变。方法:4周龄健康豚鼠40只,随机分成形觉剥夺实验组和年龄匹配正常对照组各20只。形觉剥夺实验组分为剥夺1,4,7和14d4个亚组,右眼为剥夺眼,采用半透明眼罩遮盖诱导轴性近视,左眼不予处理。对剥夺前后实验组和对照组双眼屈光度、眼轴进行测量,并对后极部巩膜进行HE染色光镜观察和透射电镜观察。结果:形觉剥夺7d近视程度和眼轴长度改变迅速,之后减慢并趋于平稳。4个实验亚组剥夺眼与实验前比较相对近视-0.30±0.45D,-3.65±0.78D,-6.98±0.65D,-8.68±1.12D,相对眼轴延长4.8±3.2,129.0±12.6,159.0±10.1,184.4±10.4μm。其中4,7,14d实验亚组剥夺眼与对照眼差别有统计学差异(P<0.01),剥夺眼后极部巩膜明显变薄,成纤维细胞密度降低,细胞外基质增多。1,4,7,14d实验亚组形觉剥夺眼后极部巩膜胶原纤维平均直径102.0,67.4,52.2,49.8nm,与正常对照眼比较差别有统计学意义(P<0.05)。结论:4周龄豚鼠单眼形觉剥夺4d即可出现轴性近视,1d即有巩膜病理改变,形态学改变先于生物学改变,形觉剥夺7d为近视发展高峰期。     

纤维连接蛋白在形觉剥夺眼和正常眼的差异表达

目的：探讨实验性形觉剥夺性近视眼眼轴增大的影响因素,探讨导致形觉剥夺性近视眼的巩膜改变的分子水平机制。方法：单眼遮盖20只鸡雏4周制备实验性近视模型,然后使用免疫组织化学方法检测遮盖眼和对照眼的巩膜软骨组织的纤维连接蛋白（FN）表达情况。结果：遮盖眼巩膜软骨的软骨细胞质、细胞膜和软骨囊的FN的表达水平比对照眼明显增高（P＜0.01)。结论：FN与实验性近视眼的近视形成机制有关,可能有调节眼球增大的作用。     

形觉剥夺性近视豚鼠巩膜形态学观察

目的观察形觉剥夺性近视豚鼠眼后极部巩膜的改变。方法4周龄豚鼠14只,随机分为正常对照组(Ⅰ组),形觉剥夺(FD)组(Ⅱ组)。Ⅱ组豚鼠右眼采用半透明眼罩遮盖的方法建立形觉剥夺近视模型,2周后检测其屈光度、眼轴长,并观察后极部巩膜组织的光镜、电镜改变。结果2周后剥夺眼屈光度相对于对照眼及年龄匹配对照组分别为-3.1 D±1.60 D,-3.2 D±1.72 D(P<0.01)。剥夺眼眼轴相对于对照眼(7.90 mm±0.13 mm、7.87 mm±0.17 mm,P<0.01)和正常眼(7.90 mm±0.13 mm、7.70 mm±0.16 mm,P<0.05)明显延长。剥夺眼后极部巩膜组织变薄,胶原纤维直径变小,纤维间空间增大。结论形觉剥夺刺激豚鼠眼巩膜组织变薄,其改变与人类近视巩膜组织改变相似。     

视黄酸在早期形觉剥夺性近视豚鼠后巩膜中的变化

目的检测豚鼠早期形觉剥夺性近视（FDM）眼巩膜中视黄酸（RA）的水平,探讨RA在FDM眼后极部巩膜中的作用。方法3周龄三色豚鼠30只随机分组,正常对照组6只,形觉剥夺15d组和形觉剥夺24d组各12只,左眼用气球头套分别遮盖15d和24d,右眼为自身对照。实验前后均测量屈光度,实验结束后摘除眼球,测量眼轴长,应用高效液相色谱法（HPLC）测定后极部巩膜RA含量。结果形觉剥夺15d组、形觉剥夺24d组动物实验眼诱导出明显的相对近视,且与正常组比较差异有统计学意义（F=23.053,P〈0.05）。形觉剥夺15d组、形觉剥夺24d组实验眼眼轴均长于自身对照眼（P〈0.05）。形觉剥夺15d组、形觉剥夺24d组实验眼巩膜中RA水平较自身对照眼均明显升高（P〈0.01）,但形觉剥夺15d组、形觉剥夺24d组间比较差异无统计学意义（P=0.857）。结论形觉剥夺可诱导近视,且近视程度在早期随时间递增,形觉剥夺眼眼轴增长。豚鼠早期形觉剥夺眼后极部巩膜RA含量增多,但在15～24d时段内差异无统计学意义。     

鸡形觉剥夺性近视眼形态学及bFGF免疫组织化学研究

目的 了解形觉剥夺性近视（FDM）的参与因素。方法 实验鸡40只孵化2d，经初筛分为2组，切除实验组（右眼）上下睑缘各1mm，连续缝合，制造FDM的动物模型，遮盖时间为21d，常规视网膜检影法测屈光度，A型超声测眼轴长度，光学显微镜观察眼后极部组织病理变化，免疫组织化学法测后极部巩膜、视网膜中碱性成纤维细胞生长因子（bFGF）的变化。结果 诱发明显的FDM，实验眼眼轴延长（P〈0．05），镜下见实验眼巩膜软骨层增厚、纤维层变薄，软骨层内软骨细胞数目增多。bFGF免疫组织化学染色显示，bFGF在实验眼与对照眼巩膜、视网膜均有表达，在视网膜的表达实验眼强于对照眼，实验眼的视网膜外层又强于内层，巩膜bFGF的表达在两组间无显著性差异。结论 形觉剥夺性近视中有bFGF的参与。     

N-甲基-D-天冬氨酸受体1在形觉剥夺性近视豚鼠视网膜上的表达

目的对豚鼠行形觉剥夺建立近视动物模型，观察离子型谷氨酸受体N-甲基-D-天冬氨酸受体1（N—methyl—D—aspartate receptor 1．NMDAR1）在近视豚鼠视网膜上的动态表达．探讨其在近视发病机制中的作用。方法60只三色豚鼠随机分为3组：未遮盖组（Ⅰ）、单眼遮盖2周组（Ⅱ）、单眼遮盖3周组（Ⅲ），其中右眼遮盖为实验眼，左眼为自身对照眼。对各组进行视网膜检影和A超测眼轴。分别运用免疫组化及Western Blotting法检测各组豚鼠视网膜NMDAR1蛋白表达。结果Ⅰ组双眼呈轻度远视状态．双眼眼轴差异无显著性（P〉0．05）；Ⅱ组实验眼呈轻度近视（-1.583±1.478）D，自身对照眼呈轻度远视（2.500±1.017）D：实验眼眼轴较自身对照眼轻度延长（P〈0．05）；Ⅲ组实验眼呈中度近视（-3．417±l.169）D，自身对照眼呈轻度远视（1.813±1．072）D；实验眼眼轴较自身对照眼明显延长（P〈0．05）。免疫组化显示NMDAR1主要表达在豚鼠视网膜的内核层细胞及神经节细胞。Ⅰ组实验眼视网膜上NMDAR1蛋白含量为0．338±0．314．Ⅱ组实验眼NMDAB1蛋白含量升高为0．464±0．280．Ⅲ组实验眼视网膜NMDAR1蛋白含量明显上调为0．635±0．037;实验眼视网膜上NMDAR1蛋白含量随遮盖时间延长明显上调．与自身对照眼比较差异有显著性（P〈0．05）。结论形觉剥夺可明显上调豚鼠视网膜NMDAR1的蛋白表达，形觉剥夺产生的异常视觉信号可能通过刺激谷氨酸的释放、NMDAR1过度生成，参与近视的调控。     

C57BL／6小鼠形觉剥夺性近视巩膜COLlσ2启动子区域CpG岛甲基化水平

目的研究C57BL／6小鼠形觉剥夺性近视形成和恢复期巩膜COLlα2 mRNA表达及其启动子区域CpG岛甲基化水平。方法实验研究。单眼形觉剥夺建立C57BL／6小鼠近视动物模型和恢复期动物模型,分别单眼遮盖4周（48只）和单眼遮盖4周恢复1周（24只）,另外设立正常对照组小鼠36只。实验前后分别用红外偏心摄影验光仪测量小鼠眼球的屈光状态,OCT检测小鼠眼轴长度和玻璃体腔深度。RT—PCR检测巩膜COLlα2 mRNA表达水平;硫化测序聚合酶链式反应（BSP）检测C57BL／6小鼠巩膜COLlα2启动子区域CpG岛甲基化水平。同一小鼠的实验眼和对侧眼比较采用配对t检验,不同组间比较采用独立样本t检验。结果 形觉剥夺4周,实验眼相比对侧眼形成明显的相对近视（t=-2.64,P〈0．05）,并伴有眼轴和玻璃体腔延长。形觉剥夺4周恢复1周后,相对近视和延长的眼轴和玻璃体腔长度都获得恢复。形觉剥夺4周后,实验眼和正常对照眼相比COLlcα2mRNA表达明显下降（t=3．05,P〈0．05）,形觉剥夺4周恢复1周实验眼与正常对照眼相比差异无统计学意义。形觉剥夺4周,实验眼和对侧眼及正常对照眼COLlα2启动子区域CpG岛甲基化水平差异均无统计学意义。结论小鼠单眼形觉剥夺4周可诱导出相对近视,巩膜内COLlα2 mRNA表达明显下降,但该改变与其基因启动子区CpG岛的甲基化状态无关．     

RARβ在豚鼠形觉剥夺性近视眼中的表达

目的检测视黄酸受体β（RARβ）在视网膜、脉络膜和巩膜中的表达，探讨RARβ和视黄酸（RA）对哺乳类动物形觉剥夺性近视的作用。方法采用形觉剥夺的方法建立豚鼠眼近视模型。选用1～3d龄健康三色豚鼠45只，随机分为3组，Ⅰ组为持续遮盖8周组，Ⅱ组为遮盖7周后去遮盖1周组，Ⅲ组为遮盖1周组。右眼为遮盖眼，左眼为开放对照眼。测量双眼实验前后的屈光状态及眼轴。应用免疫组织化学和RT-PCR技术检测RARβ的蛋白和mRNA表达水平。结果Ⅰ组诱导出了豚鼠明显的近视改变（P〈0．05）。Ⅱ组去遮盖眼近视度明显降低，眼轴较Ⅰ组短（P〈0．05）。Ⅲ组遮盖眼屈光度和眼轴与对照眼相比差异无显著统计学意义（P〉0．05）。Ⅰ组和Ⅲ组遮盖眼视网膜内核层RARβ蛋白表达高于对照眼（P〈0．05）。Ⅲ组遮盖眼视网膜、脉络膜和巩膜RARβmRNA表达增强（P〈0．05）。结论去除形觉剥夺可以抑制近视。形觉剥夺眼视网膜RARβ蛋白的高表达早于屈光度和眼轴的改变。RARβ在形觉剥夺眼视网膜、脉络膜和巩膜中的表达增强。     

Induced myopia associated with increased scleral creep in chick and tree shrew eyes

PURPOSE: To investigate the role of scleral creep in the axial elongation of chick and tree shrew eyes with induced myopia. METHODS: Form-deprivation myopia was induced with a diffusing occluder worn over one eye. Scleral samples from the posterior pole and equatorial regions of myopic, contralateral (control), and age-matched normal chick and tree shrew eyes were loaded in vitro with a force of 5 g for 20 minutes while creep extension was monitored. The elastic behavior of sclera from myopic, control, and normal chick eyes was also compared. RESULTS: In both chick and tree shrew, posterior and equatorial scleral samples from myopic eyes had significantly (P < 0.05) greater creep extensions than equivalent samples from control and normal eyes (n = 10, each group). Among individual tree shrews the difference in creep rate between the sample from the myopic eye and that from the control eye correlated with vitreous chamber elongation (r = 0.746, P < 0.05) and development of myopia (r = 0.792, P < 0.01) in the deprived eye. No such association was found in the data from chicks. The elastic properties of chick sclera were unaffected in form-deprivation myopia. CONCLUSIONS: In chick and tree shrew, form-deprivation myopia is associated with increased creep rate of posterior and equatorial sclera. In tree shrew, the correlation between increased scleral creep rate and vitreous chamber elongation in myopic eyes supports the hypothesis that induced changes in the axial length of the mammalian eye are mediated by changes in the creep properties of the sclera.     

小鸡形觉剥夺性近视眼后极部巩膜MMP-2与TIMP-2 mRNA表达的动态变化

目的　探讨小鸡形觉剥夺性近视眼 (form deprivationmyopia,FDM )后极部巩膜基质金属蛋白酶 2 (matrixmetalloproteinase 2 ,MMP 2 )及其特异性组织抑制剂 (tissuein hibitorofmatrixmetalloproteinase 2 ,TIMP 2 )mRNA表达的时间动态性变化。方法　 5 0只 1d龄来亨雏鸡以半透明眼罩分别遮盖右眼 4、7、14、2 1、30d制备FDM动物模型 ,每组10只 ,未遮盖眼为自身对照眼 ,并随机选取同数目同龄小鸡作为正常对照眼。实验前及预定实验时间进行视网膜检影验光和眼轴长度测量。摘除眼球 ,提取后极部巩膜总RNA ,采用一步法逆转录 聚合酶链反应检测每组小鸡后极部巩膜MMP 2、TIMP 2mRNA表达水平。结果　与正常组、自身对照组相比 ,FDM后极部巩膜MMP 2mRNA显著增高 ,TIMP 2mRNA表达明显降低 ,组间差异非常显著 (P <0 .0 1)。随遮盖时间延长 ,MMP 2mRNA表达逐渐上调 ,7～ 2 1d达最高峰 ,以后轻度下降 ,但仍维持于一较高水平 ,不同遮盖时间组间差异显著 (P <0 .0 1) ,而TIMP 2mRNA表达与之相反。自身对照组MMP 2mRNA表达较同龄正常对照组有轻度上调趋势 ,TIMP 2有下调趋势 ,但组间均无统计学差异 (P >0 0 5 )。结论　MMP 2 /TIMP 2之间动态平衡失调极可能是启动小鸡FDM巩膜细胞外基质早期主动重塑的关键     

Scleral changes in chicks with form-deprivation myopia

The sclera in myopic regions of chick eyes was studied histologically and compared to the sclera in corresponding regions of normal fellow eyes. Chicks had been monocularly deprived of form vision in the nasal half of the retina from hatching. The fellow control eye and the temporal retina of the deprived eye had normal vision. With this treatment, the resulting form-deprivation myopia and eye enlargement are restricted to the retinal region that had been form deprived. We found that the cartilaginous sclera in the myopic nasal region exhibited several differences from that in the corresponding non-myopic region: it was thicker, its cell density was lower, and the number of chondrocytes and binucleate cells was higher. In contrast, the fibrous sclera was thinner. These changes suggest that form-deprivation myopia causes an increased production of extracellular matrix and an increased level of mitotic activity in the cartilaginous sclera. As expected, the non-myopic temporal regions of experimental and control eyes did not differ in any of these parameters. The findings of the present study suggest that the eye enlargement accompanying form-deprivation myopia is not the consequence of scleral stretching but of abnormal growth.     

NGF在鸡巩膜中的表达及其与形觉剥夺性近视眼形成的关系

目的探讨神经生长因子(NGF)在鸡形觉剥夺性近视形成中巩膜中的表达和变化情况。方法鸡雏30只,随机分为3组,每组10只,于出生后第2 d将右眼以半透明眼罩遮盖作为遮盖眼,左眼开放作为对照眼。分别遮盖3、7、14d。运用免疫组织化学和原位杂交技术探测NGF蛋白及其mRNA在鸡巩膜软骨细胞中的表达。结果NGF蛋白及其mRNA均表达于巩膜的软骨细胞中尤其在双核细胞中;两者在各时间段遮盖眼巩膜中阳性细胞数均明显高于对照组(P<0.05);免疫组织化学(FDG=20.556P<0.01)和原位杂交(FDG=25.520P<0.01)在对照组(或遮盖组)各组间阳性细胞的表达数目随时间变化明显下降。结论NGF对鸡巩膜软骨层的发育和形觉剥夺性近视的形成密切相关。     

Inducing form-deprivation myopia in fish

PURPOSE: To induce form deprivation myopia in fish and investigate the role of the lens in the development of refractive error. METHODS: Tilapia (Oreochromis niloticus), approximately 4 months old and from 26 to 63 g, were divided into three groups. Translucent goggles were directly sutured over the right eye for 4 weeks to induce form-deprivation myopia; the left eye served as an untreated contralateral control. The refractive state was measured by retinoscopy. Ocular dimensions were determined from frozen sections and with ultrasound biomicroscopy, and a scanning laser system was used to determine the optical quality of excised lenses. RESULTS: After 4 weeks of form-deprivation treatment, all the deprived fish eyes showed development of significant amounts of myopia ranging from -3.75 to -26.25 D, with the average amounting to -10.27 +/- 1.14 D. Eye dimension measurements show that the vitreous and anterior chambers of the treated eye are significantly longer axially than those of the contralateral eyes. No significant change in optical quality was found between lenses of the myopic and nonmyopic eyes. The fish recovered completely from the myopia 5 days after the goggle was removed. CONCLUSIONS: Although lower vertebrates are capable of lifelong growth, their eyes are susceptible to form-deprivation myopia. Thus, the visual environment is an important factor controlling ocular development in lower vertebrates, as well as in higher ones, and eye development is not strictly genetically determined. This study also indicates that lens growth and optical development are largely independent from the refractive development of the whole eye.     

小鸡形觉剥夺性近视眼巩膜TIMP-2 mRNA表达的时间动态变化

目的 探讨小鸡形觉剥夺性近视眼(FDM)后极部巩膜基质金属蛋白酶2组织抑制剂(TIMP-2)mRNA表达水平的动态变化。方法 取1d龄来亨雏鸡以半透明眼罩分别遮盖右眼4、7、14、21、30d制备FDM动物模型,未遮盖眼为自身对照眼,并随机选取同数目同龄小鸡作为正常对照眼。实验前及预定实验时间进行视网膜检影验光和眼轴长度测量,摘除眼球,提取后极部巩膜总RNA,采用一步法逆转录-多聚酶链反应检测每组小鸡后极部巩膜TIMP-2 mRNA表达水平。结果 与正常组、自身对照组相比,FDM后极部巩膜TIMP-2 mRNA表达明显降低,组间差异非常显著(P<0.01)。随遮盖时间延长其表达降低,7～21d降低最明显,FDM组间差异显著(P<0.01)。自身对照组TIMP-2 mRNA表达水平较同龄正常对照组存在下调趋势,但组间无统计学差异(P>0.05)。结论 后极部巩膜TIMP-2表达抑制极可能作为导致巩膜ECM主动重塑的始发因素之一而参与FDM形成。     

单眼高度近视患者眼前节形态学研究

目的 了解高度近视眼眼前节形态的结构特点,探讨高度近视眼与中低度屈光不正眼的眼前节形态是否存在差异.方法 单眼高度近视患者23例（46眼）,年龄（24.1±12.4）岁（范围8～49岁）,屈光参差（8.73±4.73）D（范围1.62～16.75 D）,进行双眼间的对照研究,高度近视眼（屈光不正度数高于-6.00 D）为高度近视组,对侧眼（屈光不正度数在-5.75 D之内）为对照组.用A型生物超声仪测量中央角膜厚度和眼轴长度,Pentacam眼前节三维分析仪测量角膜前后表面曲率（中央区角膜最大与最小子午线角膜曲率的平均值）或曲率半径、角膜前后表面非球面形态（30°范围的平均Q值）、角膜前后表面散光、前房深度、前房角及前房容积.采用SPSS 15.0统计软件,配对t检验用于双眼间的参数比较,直线相关用于两参数间的相互关系分析.结果 高度近视组的眼总散光、眼轴长度及跟轴长度/角膜曲率半径（AL/CR值）分别为（1.43±1.26）D、（27.45±1.63）mm及3.60±0.22;对照组的眼总散光、眼轴长度及AL/CR值分别为（0.93±0.92）D、（24.19±1.41）mm及3.16±0.12,两组比较均有统计学意义（t=-2.539,P〈0.05;t=8.606,P〈0.01;t=8.167,P〈0.01）.高度近视组的角膜前、后表面曲率,角膜前、后表面散光,角膜前、后表面非球面系数Q值,前房深度,前房角及前房容积分别为（44.1±1.8）D、（-6.3±0.3）D,（1.4±1.0）D、（0.3±0.2）D,-0.35±0.13、-0.16±0.18,（3.12±0.30）mm,（38.7±4.2）°及（178±37）mm^3;而对照组的上述参数分别为（44.1±1.8）D、（-6.4±0.3）D,（1.3±0.8）D、（0.4±0.2）D,-0.33±0.10、-0.20±0.19,（3.08±0.32）mm,（38.8±5.8）°及（175±40）mm^3;两组差异均无统计学意义（P〉0.05）.眼轴长度与等效球镜度在高度近视组和对照组均显示了高度线性相关关系（高度近视组r=0.662,P〈0.01;对照组r=0.618,P〈0.01）.在高度近视组和对照组,角膜顶点曲率半径与等效球镜度无相关性（高度近视组r=0.287,P〉0.05;对照组r=0.261.P〉0.05）.结论 高度近视眼与中低度屈光不正眼眼前节形态无明显差异,而眼轴长度存在明显差异,高度近视眼眼轴明显延长.     

角膜放射状切开术后5—8年屈光稳定性观察

目的观察角膜放射状切开术（RK）后屈光的长期稳定性问题,为临床手术提供指导。方法选择有完整的资料并由一人进行RK手术的患者48例（96只眼）,由专人对随访患者进行检查,详细记录视力、屈光度及眼部的临床情况。结果48例（96只眼）患者,术后5～8年平均屈光度为（-2.14±2.36）D,与术后1周时的-0.68D有差别（P<0.001）。高度近视与中度近视在RK术后5～8年的屈光度变化分别为（-1.86±2.06）D和（-0.94±1.06）D,差别有显著的意义,P<0.05。术后5～8年,96只眼的平均屈光度变化为（-1.46±1.75）D,与Waring和Sawelson的研究比较,差别有显著性。结论本组患者的随访结果显示,RK术后仍有向近视发展的倾向,尤其是高度近视。     

Dynamic changes of ocular biometric parameters: a modified form-deprivation myopia model of young guinea pigs

AIM: To evaluate the dynamic ocular biometric changes of a modified form-deprivation myopia model in young guinea pigs. METHODS: The animals were randomly assigned to two groups: the monocularly deprived facemask group (MDF, with all the right eyes covered, n=24) and the normal control group(free of facemask, n=24). Each group was then equally divided into four subgroups which were followed up for 2, 4, 6 and 8 weeks, respectively. Parameters measured from every eye included refraction, corneal curvature, axial length and the dry weight of sclera at the posterior pole. RESULTS: All the facemasks remained in place during the follow-up. The covered eyes developed myopia with the vitreous chamber lengthening and the dry weight of posterior sclera reduced at each time point compared with the contralateral uncovered(P<0.05 at all time points). The changes had a linear correlation with the deprivation time (P<0.05). There were no significant differences in all the parameters between the uncovered eyes of MDF group and the normal control group (P>0.05 at all time points). CONCLUSION: Monocular form deprivation with the facemask is highly effective and non-invasive in inducing axial myopia in guinea pigs. The axial myopia is mainly caused by the increased vitreous chamber length and the weakened posterior sclera rigidity. The form-deprivation eye didn't interfere with the natural development of the contralateral eye.