近视性屈光参差的功能性磁共振成像研究

目的利用血氧水平依赖性功能性磁共振成像(BOLD-fMR I)技术,探索人类近视性屈光参差是否对大脑皮层功能和结构造成影响。方法采用无磁MR I专用眼镜纠正屈光不正,以1.5T磁共振成像系统采集8例近视性屈光参差者枕叶视皮层兴趣区BOLD-fMR I数据,比较双眼皮层激活部位及范围的不同,及视力较差眼屈光纠正前后皮层激活情况的变化,分析其改变特点及机制。结果矫正屈光基础上,近视性屈光参差者双眼激活范围没有明显差异(P>0.05);视力较差眼屈光矫正前后皮层激活范围有明显差异(P<0.05)。结论人类近视性屈光参差可能没有发生明显的皮层功能损害及优势眼的转移;配镜可明显提高视力较差眼的皮层激活,应尽早配镜或手术矫正。     

屈光参差性弱视患儿综合治疗效果的相关因素研究

目的：探究影响屈光参差性患儿综合治疗效果的相关因素,为临床干预提供理论依据。

方法：选取我院2013-10/2014-10间收治的100例屈光参差性弱视患儿,经过6～18mo的治疗后根据治疗效果分为A、B、C三组,A组54例,治疗效果判定为治愈; B组34例,治疗效果判定为进步; C组12例,治疗效果判定为无效。对其年龄、依从性、屈光参差程度、屈光参差类型、弱视程度、注视性质进行分析。

结果：三组患者之间屈光参差类型差异无统计学意义(P>0.05),而三组患者之间年龄、治疗依从性、屈光参差程度、弱视程度、注视性质相比差异有统计学意义(P<0.05)。通过回归方程分析各因素对综合治疗效果影响程度依次为弱视程度、屈光参差程度、注视性质、年龄、依从性。

结论：屈光参差性患儿综合治疗效果与年龄、治疗的依从性、屈光参差程度、弱视程度、注视性质密切相关,而与患儿的屈光参差类型无明显的相关性。     

儿童屈光参差性弱视立体视觉中枢区激活的fMRI远期研究

目的：运用血氧水平依赖性功能核磁共振成像技术(BOLD-functional magnetic resonance imaging,BOLD-fMRI)阶段性评价屈光参差性弱视儿童在规范弱视训练后视皮质相关功能区激活情况。

方法：收集先期研究及后续收集屈光参差性弱视儿童共13例进行任务态组块模式(Blocks)的功能磁共振(fMRI)研究,采用前后对照t检验对规范弱视治疗18mo和24mo及终止治疗6mo后的脑功能激活数据进行分析。图像处理平台为Matlab 7.12.0.635的SPM8软件。

结果：各阶段功能区激活主要集中在左枕叶(Brodmann 18区)、枕中回(Brodmann 19区)、边缘叶(Brodmann 19区)、双侧顶上小叶(Brodmann 7区)、右枕叶舌回(Brodmann 17区),弱视治疗24mo激活范围无明显扩大,差异无统计学意义(mean T=1.014,P>0.01),终止治疗6mo后激活范围差异无统计学意义(mean T=0.9793,P>0.01)。

结论：屈光参差性弱视治疗2a后视中枢基本稳定,持续弱视治疗对于视中枢功能重建无显著作用。     

高度近视合并屈光参差性弱视患者与非弱视患者空间扭曲特征对比分析

目的 探讨高度近视合并屈光参差性弱视患者与非弱视患者空间扭曲特征差异。方法 选取2019年5月至2020年1月就诊于北京同仁医院的高度近视合并屈光参差患者50例作为研究对象。根据患者最佳矫正视力(BCVA)(≥0.8)分为非弱视组和弱视组,非弱视组患者21例,弱视组患者29例。采用国家医疗保健器具工程技术研究中心开发研制的视感知觉检查评估系统检测患者空间扭曲情况,检测时视标“○”沿着3个直径分别为3.6°、4.4°和5.2°的同心圆随机闪现,受试者将“+”套入“○”后点击鼠标,将结果记录为空间扭曲距离(SDD)和空间扭曲角度(SDA),两者计量单位分别为像素和度(°),箭头的头尾距离为SDD,与水平线夹角为SDA,在小、中、大三个同心圆分别记录为SDDs、SDDm、SDDl和SDAs、SDAm、SDAl。使用SPSS 22.0对数据进行统计学分析。结果 弱视组患者双眼SDD较非弱视组明显增大,除SDDm外(P=0.20),SDDs和SDDl两组间差异均有统计学意义(均为P<0.05);弱视组患者双眼SDA较非弱视组明显增大,除SDAm外(P=0.25),SDAs和SDAl两组间差...     

屈光参差及其矫正对双眼视觉的影响

目的观察成人屈光参差患者接受准分子激光原位角膜磨镶术(LASIK)后双眼视觉情况,探讨影响双眼视觉形成和恢复的主要因素及LASIK与戴框架眼镜对双眼视觉恢复作用的异同。方法收集首都医科大学附属北京同仁医院在2003年6月至2005年3月期间行LASIK手术的屈光参差病例并进行随访,共收集到资料完整者43例,包括单纯性近视性屈光参差8例和复性近视性屈光参差35例。其中男性13例,女性30例;平均年龄(27.907±6.361)岁(15～42岁);最小屈光参差值为2.50 D,最大屈光参差值为10.75 D,平均为(4.866±2.059)D;平均屈光度为(-7.55±3.33)D,平均裸眼视力为0.08±0.07,术前、术后3个月及术后6个月进行立体视觉检查,颜氏立体图检查≤60 s为有中央立体视;80～800 s为周边立体视;0为无立体视。以4D为界,按屈光参差差值大小将病例分为2组,检查LASIK术后3个月及6个月屈光参差矫正情况及视力、双眼视觉恢复情况。采用SAS软件进行统计学分析。结果2例患者术前有正常近立体视,7例为周边立体视,34例为立体盲。术后3个月时,15例患者有正常近立体视,23例有周边立体视,5例为立体盲。术后6个月时,23例患者有正常近立体视,16例有周边立体视,仅4例未检出立体视。术后3个月及6个月的近立体视结果与术前近立体视结果比较差异有统计学意义(P<0.000 1),术后3个月与术后6个月相比差异无统计学意义。屈光参差差值大于4D组在术后3个月时有4例检出正常立体视,18例为周边立体视,4例为立体盲。屈光参差差值小于4D组术后3个月立体视结果显示11例正常,5例为周边立体视,1例为立体盲,二者相比P=0.002 3。术后6个月屈光参差差值大于4D组仍是4例立体视正常,19例为周边立体视,3例为立体盲;而4D以下组有12例正常,4例为周边立体视,1例为立体盲,2组立体视结果相比P=0.001 4,差异有统计学意义。结论视力、屈光参差的程度和性质、发生屈光参差的时间和有无斜视是影响立体视恢复的主要因素。LASIK手术矫正成人屈光参差后,可以提高融合功能,并可能恢复正常或部分立体视,效果优于戴框架眼镜。     

准分子激光手术在矫治儿童严重屈光参差性弱视中的作用

儿童严重屈光参差患者的弱视发生率高达66.67%,其中28.30%患儿终致视力残疾.近十年准分子激光手术矫治儿童严重屈光参差的研究表明,该手术是安全、有效的,可预测性及稳定性均较好,为儿童屈光参差性弱视治疗提供了一个良好的条件.术后进行规范的弱视治疗,提高了治愈率,降低了致残率.然而,儿童屈光手术矫治起始年龄、等值球镜的矫治范围、术后角膜剩余厚度等有待规范.术后儿童角膜修复机制的研究有待深入.     

THE CAT AS A MODEL FOR VISUAL DEPRIVATION

Both behavioural and neurophysiological changes can be observed in cats that have experienced interference with their normal visual environment. This visual deprivation may result from alterations to the path of light forming the normal image on the retina, and includes changes that cause the image to fall on an inappropriate part of the retina so that normal binocular interactions are affected. While some neurophysiological changes can be observed at the level of the lateral geniculate nucleus they become more prominent as information reaches the visual cortex, where cells commonly receive neural excitation from both eyes and require the information to come from corresponding parts of the two retinas and that the stimulus should have appropriate orientation and direction of movement. Many of the observations of deprivation in animals have clear parallels in the human environment.     

Effect of induced anisometropia on stereopsis and surgical tasks in a simulated environment

Purpose:To quantitatively correlate the loss of stereopsis by induced anisometropia with its effect on tasks that require binocular vision and stereopsis, such as ophthalmic surgery in a simulated environment.Methods:Thirty-nine ophthalmic residents with best-corrected visual acuity of 20/20 or better OU, with normal binocular vision and stereopsis, were recruited for the study. Anisometropia was induced using spherical and cylindrical trial lenses from +1D to +5D in a trial frame. The residents performed an anterior chamber navigation exercise on the EYESi simulator and the surgical score at baseline and for each level of induced anisometropia was noted. Near stereopsis was assessed by the Randot test and TNO test at baseline and for each level of induced anisometropia.Results:Stereoacuity on the Randot test and TNO test were 30 (95% CI, 25.9–34.1) and 44.4 (95% CI, 28.5–60.3) arcseconds, respectively which reduced to 65.5 (95% CI, 48.7–82.3) and 75.9 (95% CI, 15.5–136.3) arcseconds at anisometropia of +1D Sph (P < 0.001) and 380 (95% CI, 309.9–450.1) and 1922.1 (95% CI, 1582.5–2261.7) arcseconds for +5D Sph, respectively for the two tests, (P < 0.001). The corresponding surgical score reduced from 93.8 (95% CI, 91.1–96.7) to 87.5 (95% CI, 79.2–95.8, P < 0.001) for 1 DSph and 55.97 (95% CI, 38.3–73.7, P < 0.001) for 5DSph. There was a strong negative correlation between stereopsis scores and surgical task scores (Spearman''s rho -0.86, P value <0.001) Similar changes were seen for anisometropia induced with cylindrical powers.Conclusion:Induced anisometropia is associated with a significant diminution in surgical task scores in a simulated environment and this is correlated with the deterioration in stereoacuity. Assessment of stereopsis may be included as a regular part of the screening procedure for ophthalmic trainee residents.     

The clinical importance of spectacle lens base curves

This paper discusses the importance of spectacle lens base curves to the practice of optometry. The base curve is defined. Principles of spectacle lens design, and the role of the base curve in spectacle lens design, are explained. Current practices of manufacturers and surfacing laboratories concerning base curves are discussed, as is the role of the optometrist in specifying and measuring lens curves     

单眼行LASIK或LASEK术后疗效观察

目的:探讨单眼行准分子激光原位角膜磨镶术(laserin situkeratomileusis,LASIK)或准分子激光上皮下角膜磨镶术(laser epithelial keratomileusis,LASEK)治疗单眼近视所致屈光参差的效果。方法:采用对单眼等效球镜度>-2.50D的近视性屈光参差患者62例,进行单眼LASIK或LASEK手术。术眼及非术眼手术前后平均屈光度、屈光参差度数、最佳矫正视力和裸眼视力进行评价,术后随访6~24mo。结果:术眼术前平均等值球镜度数为-3.66(-2.50~-6.25)D,术后减少至-0.62(0.00~-1.00)D。LASIK或LASEK对平均等值球镜改变为-3.38(-2.50~-5.50)D。术前两眼平均屈光参差为-3.25(-2.50~-6.25)D,术后减少至-0.85(0.00~-1.75)D。术前术后最佳矫正视力(BCVA)范围均为0.6~1.0,平均最佳矫正视力从术前0.8提高到1.04;术后裸眼视力≥1.0者59眼,平均裸眼视力从术前的0.1提高至术后的1.0。非术眼术前平均等值球镜度数为-0.85(+0.25~-1.50)D,术后平均等值球镜度数为-1.85(-0.50~-3.50)D,平均裸眼视力从术前的0.5术后下降至0.1。结论:单眼LASIK或LASEK治疗近视性屈光参差虽然能提高患眼的最佳矫正视力和裸眼视力,解除单眼近视、散光所致的屈光参差对眼镜或角膜接触镜不能耐受的痛苦,而且对恢复双眼单视功能具有积极意义,但是同时我们也发现术后非术眼有近视加深的趋势,而且非术眼原近视度数越高近视加深越快越多。