角膜屈光手术后屈光回退的手术治疗进展*

屈光回退是角膜屈光手术后的并发症之一,其治疗方法主要为药物治疗和手术治疗。对于需要再次手术的患者,应根据初次手术方式、距离初次手术时间、回退度数,在充分评价角膜情况后合理选择增效术,确保手术的安全性和有效性。目前,准分子激光原位角膜磨镶术和飞秒激光小切口角膜基质透镜取出术是治疗近视和近视散光的主要手术方式。本文就两者术后屈光回退手术治疗的适应症、不同增效术的优缺点及注意事项作一综述。     

皮质类固醇激素冲击疗法治疗LASIK术后屈光回退的观察

目的:观察皮质类固醇激素冲击疗法对准分子激光原位角膜磨镶术(excimer laser in situ keratomileusis, LASIK)治疗近视术后发生屈光回退的治疗效果, 探讨此方法在临床应用的可能性.方法:对LASIK术后发生屈光回退的近视眼患者24例(48眼)采用皮质类固醇激素冲击疗法:每天9次0.1 %氟美童滴眼液点眼, 3周后改为每天4次逐周递减再治疗4周.治疗后进行了6个月的临床观察, 评价患者的视力和屈光度改变.结果:LASIK术后出现屈光回退的病例经激素治疗后视力得到改善, 屈光状态得到改变, 治疗后3周与7周的效果差异不显著.药物治疗中有激素性高眼压和其他激素副作用产生, 经降眼压治疗后未对视功能产生明显影响.结论:皮质类固醇激素冲击疗法治疗LASIK术后屈光回退并发症安全有效, 是再次LASIK手术治疗屈光回退的补充.     

准分子激光原位角膜磨镶术的护理体会

准分子激光原位角膜磨镶术（LASIK）是目前安全性、准确性、稳定性以及疗效的预测性都较好的一种屈光不正矫治术．是目前治疗近视及近视散光首选的屈光手术之一。其原理是用显微板层成形系统掀开一个角膜瓣．在瓣下角膜基质层上用准分子激光根据近视、远视和散光度数进行精确切削。我院于2008年2月从德国引进世界上先进的第八代爱丽丝智能高速扫描准分子激光治疗系统。自4月份开展该术以来。共有212例（408只眼）患者要求手术,通过术前资料评估及术前检查．筛查确定出198例进行LASIK术。通过术前的心理护理、术中密切配合以及术后的详细指导及定期复查随访．疗效满意．现将护理体会总结如下。     

光诱导角膜交联及检测技术的研究进展

由于圆锥角膜疾病导致越来越多的人患有近视,常见的矫正方法有佩戴近视眼镜、隐形眼镜等.随着科技的进步,利用光对近视等眼科疾病进行屈光矫正已经成为当前临床中常用的方法.使用光诱导角膜胶原蛋白发生交联,从而达到治疗圆锥角膜疾病、提高患者视力水平的目的,这是一种新型的光治疗眼睛疾病的方法.同时这种方法由于无侵入性、对操作者能力...     

角膜生物力学的测量及临床应用进展

摘要：角膜是重要的屈光间质,约占眼光学系统总屈光力的70％;因其特殊的生理结构,可表现出复杂的生物力学性质。随着近年来科学技术的进步,用于测量角膜生物力学的方法也在不断更新,获得的生物力学参数也更加精确。越来越多的国内外研究团队将对角膜生物力学的研究同临床相结合,发现当角膜形态发生变化时,其生物力学参数也会发生相应的改变。因此,可以通过对患者角膜生物力学的测量来判断病变的发展程度,也可以根据所测得的力学参数来进行手术设计,甚至可以初判患者的愈后情况。但在角膜生物力学方面的研究仍缺乏深度,对其与部分临床疾病的联系仍缺乏充分的认知,仍需探讨如何将角膜生物力学检查更好地服务于临床。本文将对角膜生物力学的离体、活体测量方法及其目前在圆锥角膜、青光眼、翼状胬肉、屈光不正及屈光不正的矫正等临床方面的应用研究作一综述。     

手术治近视 三思而后行

人类对近视眼的研究已数百年。近些年,角膜激光手术作为治疗近视眼的一种新方法受到了许多患者和医生的推崇,但也引起了很大争议。英国《星期日泰晤士报》曾报道：“由于担心患者的长期安全,政府医疗监督部门正在阻止国家医疗服务系统进行眼部激光手术”。而美国的《眼科学》杂志也指出,“此类眼部手术的失败率是1／10,     

飞秒激光在白内障手术中的应用新进展

飞秒激光辅助的白内障手术是目前最热门的白内障手术之一。即在计算机系统引导下利用飞秒激光进行透明角膜切口的制作,晶状体核裂解和晶状体前囊膜的切开,明显降低了传统超声乳化手术中的并发症,具有十分广阔的临床应用前景。然而飞秒激光辅助的白内障手术目前仍然处于临床应用初级阶段,其昂贵的价格是影响其研究和应用的主要原因,手术安全性及远期屈光效果仍然需要长期的随访观察。本文根据文献资料,就飞秒激光在白内障手术中的优势及临床应用的局限性进行综述。     

手术治近视 三思而后行

人类对近视眼的研究已数百年。近些年,角膜激光手术作为治疗近视眼的一种新方法受到了许多患者和医生的推崇,但也引起了很大争议。英国《星期日泰晤士报》曾报道：“由于担心患者的长期安全,政府医疗监督部门正在阻止国家医疗服务系统进行眼部激光手术”。而美国的《眼科学》杂志也指出,“此类眼部手术的失败率是1／10,     

吉西他滨眼内应用抑制兔眼白内障术后 后囊膜混浊的实验研究

目的：研究眼内应用浓度为5mg／ml的吉西他滨（GEM）对于后囊膜混浊的抑制作用。方法：12只（24眼）实验动物随机分为A、B二组,A组为治疗组,B组为对照组。所有的实验动物均进行晶状体囊外摘除＋人工晶体植入术。A组术中应用5mg/ml吉西他滨溶液作水分离;B组术中应用平衡盐溶液作水分离。术后定期观察角膜水肿,评价PCO及进行角膜内皮细胞分析。结果：术后第1天,第3天,第7天两组角膜水肿的例数均无差异。术后第二周,两组后囊膜发现不同程度混浊,第四周后囊膜混浊程度分级,对照组中央后囊明显混浊;角膜内皮细胞分析显示两组的角膜内皮数量明显低于术前,比较两组的角膜内皮数量减少量无统计学意义。结论：实验显示眼内应用5mg／ml吉西他滨后囊膜混浊程度较对照组明显轻。尽管眼内应用有导致眼内组织毒性反应的可能性,但通过用药方法的改进和保护措施的加强是可以有效避免或减轻的,因此吉西他滨是一种有潜力的预防后发性白内障的侯选药物。     

角膜新生血管的治疗新进展

角膜本身无血管,毛细血管网围绕角膜缘,如果血管超越角膜缘进入透明区即为病理性。角膜新生血管不是一种独立的角膜病,而是一种病理改变。由于维持角膜无血管的平衡因素被破坏,角膜缘的毛细血管侵入角膜周边部1-2 mm,即可视为角膜新生血管(CNV)形成1。随着它对感染的消除、创伤愈合、抑制免疫介导的角膜溶解有一定作用,但其结构和功能不完善,容易发生血浆渗漏,造成角膜水肿、脂质沉着以及激发的角膜瘢痕化,严重影响视力;也使角膜移植排斥反应的发生率大大增加。CNV的生长有利于病原微生物的清除和组织的修复,但严重影响了角膜的透明性,导致一系列的并发症,破坏眼球的完整性,目前国内外对治疗角膜新生血管的药物进行了大量的研究,希望通过不同的药物、不同的治疗方法解决这个大难题。     

OCTA用于检测不同屈光人群的黄斑区视网膜密度和厚度及其相关性分析

目的:采用光学相干断层扫描血管成像技术(OCTA)检测不同屈光人群的黄斑区视网膜密度及厚度并分析其相关性。方法:选取2016年2月～2018年2月我院收治的近视患者200例为研究对象,根据等效球镜度数的差异将其分为轻度近视组(-0.50～-2.75D)52例、中度近视组(-3.00～-5.75D)46例、高度近视组(-6.00～-8.75D)48例、超高度近视组(≤-0.90D)54例。所有患者均进行OCTA检测,比较各组患者黄斑区不同区域视网膜血管密度以及厚度的差异。结果:轻度近视组、中度近视组、高度近视组、超高度近视组等效球镜均呈逐渐降低趋势,而眼轴长度均呈逐渐升高趋势,各组间对比差异有统计学意义(P0.05)。超高度近视组患者中心凹、中心凹旁、颞侧、上方、鼻侧、下方视网膜血管密度和中心凹、中心凹旁、颞侧、上方、鼻侧、下方视网膜厚度相比轻度近视组、中度近视组、高度近视组均显著降低(P0.05)。经Pearson相关性结果显示:近视屈光人群的黄斑中心凹以及上方视网膜血管密度以及视网膜厚度呈正相关关系(P0.05)。结论:采用OCTA检测不同屈光人群的黄斑区视网膜密度及厚度,结果表明近视屈光度患者的黄斑区视网膜密度增加以及黄斑区视网膜厚度的增厚呈正相关关系。     

近视眼LASIK术后眼高阶像差变化

探讨近视眼LASIK术后眼波阵面像差高阶像差各项的变化。方法:采用NIDEK OPD-Scan ARK-1000型波前像差扫描系统对LASIK治疗近视的62只眼在术前术后眼的波前像差进行了评估。在术前、术后10天、术后一个月分别测量眼的波阵面像差。比较6mm瞳孔下高阶像差各项的变化。结果:在全部接受检查的病例中,总的高阶像差(RMSh)均有所增加。从Zernik各项绝对值来看,球差C12变化最大。术后10天比术前增加6．7742倍(P=0．0001)。其次是彗差C7 C8(X轴、Y轴上的彗差),分别增加了4．883倍(P=0．0001)、3．7523倍(P=0．0001)。结论:LASIK术后眼的总的高阶像差均方根值(RMSh)明显增加,尤其是球差和彗差;但在恢复过程中高阶像差有下降的趋势。用像差仪来指导和评估LASIK等屈光手术可以更全面、更准确。     

Visual-optical characteristics of caged and semifree-ranging monkeys

Five species of macaques and one species of mangabey comprising a total of 324 monkeys (132 males and 192 females) were given visual examinations which included measures of corneal curvature, depth of the anterior chamber, thickness of the lens, depth of the vitreous chamber, total axial length, total power of the eye and intraocular pressure as well as the refractive error of eye under cycloplegia in the anesthetized monkey. Cercocebus and Macaca mulatta demonstrated the greatest amount of myopia and Macaca fascicularis the least, with M. speciosa, M. fuscata, and M. nemestrina in order between these extremes. The M. nemestrina eye approximates that of the chimpanzee in size and relationship of the components. The findings indicate that males have larger eyes than females, the curvature of the cornea decreases as the axial length increases, and there is a close relationship between the length of the eye and the amount of myopic refractive error. There is some evidence that amount of myopia and the percentage of animals showing a myopic refractive error are related to the visual conditions and the behavior patterns of the different species.     

Biofeedback of accommodation to reduce functional myopia

Functional myopia may be defined as the refractive condition of the eye due to spasm of the ciliary muscle. As a result of the ciliary muscle spasm, the crystalline lens becomes more convex, creating a myopic refractive condition. The normal increase and decrease in the refractive power of the crystalline lens is known as accommodation and is controlled by the autonomic nervous system innervation to the ciliary muscle. Previous studies have reported that voluntary control of accommodation is possible by biofeedback training (Cornsweet & Crane, 1973; Randle, 1970). The present research investigated the application of biofeedback control of accommodation to reduce functional myopia. A double-reversal, multiple-baseline design was used to conduct the experiment. The results revealed that the three adult male subjects achieved the preset criterion, a 1/2-diopter reduction from initial baseline to a subsequent baseline. Further analysis of the data revealed even greater changes between initial baseline and feedback periods. Although generalization to a nonexperimental environment was not trained, each subject showed a reduction in myopia and an increase in visual acuity. The results of the experiment clearly demonstrated that functional myopia is subject to voluntary control.The research presented in the text was submitted in partial fulfillment of the requirements for the degree of doctor of philosophy in the Ferkauf Graduate School, Yeshiva University. The author wishes to express appreciation to his dissertation committee, professors Carl Auerbach, Abraham Givner, and Allan C. Goldstein. Also, appreciation is given to Ralph Dippner and John Orzuchowski for their assistance.     

Animal Models of Myopia: Learning How Vision Controls the Size of the Eye

As they grow up, approximately 25% of children in the United States become myopic (nearsighted). A much smaller fraction become significantly hyperopic (farsighted), while the majority develop little or no refractive error and are emmetropic. The causes of refractive error, especially myopia, have been the subject of debate for more than a century. Some have held that myopia is primarily an inherited disorder, and others, that myopia is caused by protracted near work and, especially, by accommodation during protracted near work. It has not been possible, based solely on clinical observations, to resolve the relative roles of heredity versus environment in the development of refractive error. In the mid-1970s, several animal models were developed to study the mechanisms underlying refractive error. Using animal models, it was found that the visual environment exerts a powerful influence on refractive state by controlling the axial length of the eye during the postnatal developmental period. Although several species have been examined, three have emerged as primary models and have played complementary roles: tree shrews (mammals closely related to primates), chicks, and monkeys. Each has advantages and disadvantages. Collectively, research on animal models has provided evidence on three issues, namely that (1) the visual environment can produce refractive error; (2) an emmetropization mechanism normally guides eyes to low refractive error; and (3) under-accommodation, rather than excessive accommodation, may cause myopia. Two decades of research on animal models have provided criteria that may be used to evaluate the usefulness of additional species as models of emmetropization.     

Measurement of Myopia and Normal Human Choroidal Thickness Using Spectral Domain Optical Coherence Tomography

Myopia is a common ophthalmic deficiency. The structure and function of choroid layer is assumed to be associated with myopia. In this study, a laboratory developed spectral domain optical coherence tomography scanning system is used to image human eyes. The axial resolution of the system is about 7 μm, and the acquisition rate is 100 kHz. Firstly, a cross-sectional image was acquired by averaging 100 images from imaging posterior segment of each eye. The choroid thickness was measured by 11 discrete points. The average thickness of normal human eyes was (0.296 ± 0.126) mm, whereas the average choroid thickness of myopic eyes was (0.220 ± 0.095) mm. Afterwards, the T test is used to calculate the data statistically. The analysis of the final result is based on the average thickness measured and the thickness of each measuring point. There was a significant difference in choroid thickness between myopia and normal eyes (P value < 0.01), which indicates that the choroid thickness of myopia was significantly thinner than that of normal eyes. Besides, there are findings that the choroidal thickness in nasal side is thinner than that in the fovea and temporal side in each eye. The choroidal thickness on temporal side in myopia eye has the most significant difference comparing with that in normal eye. The comprehensive evaluation of myopia and normal choroidal thickness using spectral domain optical coherence tomography may provide an important reference for the development of medical methods for diagnosis and treatment of myopia.     

Biophysical properties of corneal cells reflect high myopia progression

Myopia is a common ocular disorder with significant alterations in the anterior ocular structure, including the cornea. The cell biophysical phenotype has been proposed to reflect the state of various diseases. However, the biophysical properties of corneal cells have not been characterized during myopia progression and their relationship with myopia remains unknown. This study characterizes the biophysical properties of corneal cells in normal, myopic, and recovered conditions, using two classical myopia models. Surprisingly, myopic corneal cells considerably reduce F-actin and microtubule content and cellular stiffness and generate elevated traction force compared with control cells. When myopia is restored to the healthy state, these biophysical properties are partially or fully restored to the levels of control cells. Furthermore, the level of chromatin condensation is significantly increased in the nucleus of myopic corneal cells and reduced to a level similar to healthy cells after recovery. These findings demonstrate that the reversible biophysical alterations of corneal cells reflect myopia progression, facilitating the study of the role of corneal cell biophysics in myopia.     

Systemic 7-methylxanthine in retarding axial eye growth and myopia progression: a 36-month pilot study

The adenosine antagonist 7-methylxanthine (7-mx) works against myopia in animal models. In a clinical trial, 68 myopic children (mean age 11.3 years) received either placebo or 7-mx tablets for 12 months. All participants subsequently received 7-mx for another 12 months, after which treatment was stopped. Axial length was measured with Zeiss IOL-Master and cycloplegic refraction with Nikon Retinomax at ?6, 0, 12, 24, and 36 months. Axial growth was reduced among children treated with 7-mx for 24 months compared with those only treated for the last 12 months. Myopia progression and axial eye growth slowed down in periods with 7-mx treatment, but when the treatment was stopped, both myopia progression and axial eye growth continued with invariable speed. The results indicate that 7-mx reduces eye elongation and myopia progression in childhood myopia. The treatment is safe and without side effects and may be continued until 18–20 years of age when myopia progression normally stops.     

Identification of apolipoprotein A-I as a "STOP" signal for myopia

Good visual acuity requires that the axial length of the ocular globe is matched to the refractive power of the cornea and lens to focus the images of distant objects onto the retina. During the growth of the juvenile eye, this is achieved through the emmetropization process that adjusts the ocular axial length to compensate for the refractive changes that occur in the anterior segment. A failure of the emmetropization process can result in either excessive or insufficient axial growth, leading to myopia or hyperopia, respectively. Emmetropization is mainly regulated by the retina, which generates two opposite signals: "GO/GROW" signals to increase axial growth and "STOP" signals to block it. The presence of GO/GROW and STOP signals was investigated by a proteomics analysis of the retinas from chicken with experimental myopia and hyperopia. Of 18 differentially expressed proteins that were identified, five displayed an expression profile corresponding to GO/GROW signals, and two corresponded to STOP signals. Western blotting confirmed that apolipoprotein A-I (apoA-I) has the characteristics of a STOP signal both in the retina as well as in the fibrous sclera. In accordance with this, intraocular application of the peroxisome proliferator-activated receptor alpha agonist GW7647 resulted in up-regulation of apoA-I levels and in a significant reduction of experimental myopia. In conclusion, using a comprehensive functional proteomics analysis of chicken ocular growth models we identified targets for ocular growth control. The correlation of elevated apoA-I levels with reduced ocular axial growth points toward a functional relationship with the observed morphological changes of the eye.