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1、Infant Vision,婴幼儿视力检查,钱学翰 医学博士 副主任医师 Q 天津医科大学眼科中心 天津医科大学视光学院 斜视与小儿眼科 022-58280703 18920395031 Depts. of Pediatric Ophthalmology & Strabismus,What do children see and how do we know? 孩子看的好吗？如何知道？,The optics of vision 屈光系统,正视化 Emmetropization,眼轴变长 角膜曲率变小 晶状体屈光力变小,The Neurology of vision 视觉神经学,我们并非生来即拥
2、有1.0的视力光学系统发育成熟 Optics of the eye matures-眼球增大 Globe enlarges-调节更精准 Accommodation becomes more precise,The Neurology of vision 视觉神经学,我们并非生来即拥有1.0的视力视网膜发育成熟 Retina matures-视锥细胞向中心凹移行 Cones migrate centrally-视锥细胞变长&感光效能提高Cones elongate and become more efficient,The Neurology of vision 视觉神经学,我们并非生来即拥有1
3、.0的视力视神经发育成熟(髓鞘化) Optic nerve matures (myelination)视放射形成(髓鞘化) The optic radiations mature (myelination),The Neurology of vision 视觉神经学,我们并非生来即拥有1.0的视力 1视皮质形成(新的连接建立) 1 Visual cortex matures-new connections-依赖于视觉经验和有效刺激This requires experience & quality stimulation视皮层联合区发育成熟(建立新的连接) Association visual
4、 cortex matures (new connections),Vision is a complex task,精细视觉中央视力Detail vision-visual acuity-优质的光学系统 (优质镜头)High optical quality (“good camera”) -视网膜敏感性 (优质底片）Retinal sensitivity (“high quality film”)“高密度胶片”-许多光感受器“Fine grain film” =lots of photoreceptors“高感光度胶片”-光感受器对光敏感“Sensitive film” = sensitiv
5、e photoreceptors,视觉的形成是一项复杂的过程,对比敏感度Contrast sensitivity色觉Color vision运动知觉Motion perception,视觉的形成是一项复杂的过程,Vision is a complex task,Pelli-Robson Contrast Sensitivity Chart,双眼视觉/深度觉Binocular vision/Depth perception更高级的视功能 Higher visual function-空间感知觉Spatial perception-面部识别Facial discrimination-视觉记忆Vis
6、ual memory,Vision is a complex task,视觉的形成是一项复杂的过程,Assessment of the infant visual system,感觉功能检查 Sensory exam-这个孩子的视觉正常吗？ Is this childs vision normal? 运动功能检查 Motor exam-这个孩子的眼球运动系统正常吗？Is this childs oculomotor system normal?,婴儿视觉系统评估,A pediatric vision conundrum:,对视觉感觉系统的检查依赖于眼运动系统功能Testing the visu
7、al sensory system depends upon the integrity of the oculomotor system.反之亦然Testing the oculomotor system depends upon the integrity of the visual system.,儿童视觉检查的一个难点：,我们如何知道一个孩子的视觉是否正常？,知道正常眼视觉功能&运动功能发育的几个重要阶段Know the normal “stages” of visual sensory & oculomotor development. 儿童并非小大人！Children are no
8、t miniature adults !- 解剖和生理学的改变Anatomic and physiologic changes- 不同年龄的特征性视觉行为改变Age-related behavioral milestones,Monocular acuity-from birth to 1 year,中心凹结构的变化 Changes in foveal structure.中心凹锥细胞发育成熟 Maturation of the foveal cones. 更致密 (图像精细化)Denser (finer grain image)更高 (捕获光子更高效)Higher (higher % of
9、photon capture),出生至一岁龄婴幼儿单眼视锐度,Monocular acuity-from birth to 1 year,出生至一岁龄婴幼儿单眼视锐度,眼球 Globe轴长由16mm增至23mmlength 16mm-23mm更大的图像会刺激诱导网膜产生更多的光感受器Larger image stimulates more photoreceptors视神经髓鞘化 Myelination of optic nerves颅内视觉传导通路的髓鞘化(髓鞘化1岁后10岁以前继续发生)Myelination of intracranial visual pathways(continue
10、s through 1st decade),Is this the whole story ?,成人眼 Adult eye 视力接近由以下因素决定的理论极限值VA is close to the theoretical limit imposed by 光感受细胞的密度 density of photoreceptors 眼的光学性能 optical properties of the eye. 婴幼儿眼 Infant eye 视力小于理论极限值 VA theoretical limit 612个月视网膜, 外侧膝状体, 视皮质的神经回路的进一步精细化 视神经,视交叉,视束髓鞘化 后段(视放射
11、),Visual Milestones 视觉里程碑,胎儿期 Gestational age 25 周29-31 周,视觉行为特征对光照有瞬目反应Blinks to light瞳孔对光反射已形成Pupillary reflex to light,Visual Milestones 视觉里程碑,出生后 Post-natal age出生时(40周) 23月龄,视觉行为特征 视力 20/400-500 (双眼) 20/100-200 (视觉电生理检查)获得全视野 (视动性眼球震颤OKN)再注视,扫视 Refixation saccades 追随人脸移动 Follows faces 注视静止目标 Fix
12、es still objects 3月时达到正视 Orthotropic by 3 mos,Visual Milestones 视觉里程碑,出生后23月龄6个月双眼视,视觉行为特征 扫视性追随 Saccadic tracking 部分婴儿3月时获得此种能力 辐辏运动 Convergence融合 Fusion 立体视 Stereopsis 视力 20/80-100 (选择性观看FPL)20/25 (视觉诱发电位VEP) 拿够小物体 Reaches small objects 识别人脸 Recognizes faces,新生儿眼中的世界 Newborn,4周龄婴儿眼中的世界,8周龄婴儿眼中的世界,
13、3月龄婴儿眼中的世界,6月龄婴儿眼中的世界,成人眼中的世界,What can children see ?,注视和追随的能力Quality of fixation-Fix & Follow,行为检查 Behavioral testing,What can children see ?,注视偏好检查 Fixation preference,行为检查 Behavioral testing,What can children see ?,视动性眼球震颤OKN,行为检查 Behavioral testing,What can children see ?,强制性选择性观看 Forced prefere
14、ntial looking (Teller acuity),行为检查 Behavioral testing,What can children see ?,视力表 Optotypes图案字母,行为检查 Behavioral testing,What can children see ?,视觉诱发电位 VEP acuity快速记录多振幅线条轨迹 Rapid display of stripes of multiple widthsERG振幅波峰与条带宽度成比例 Amplitude of EEG “spike” is proportional to stripe width,电生理检查 Elect
15、rophysiologic testing,固视和追随 Quality of Fixation Fix & follow (F & F),中心注视，稳定注视，维持注视 Central, steady, & maintained (CSM),斜视儿童注视偏好检查,Fixation Preference Test (FPT) in children with strabismus注视偏好检查主要用于探查:无法获得可信视锐度的儿童(除外患有微小斜视以及有显斜视的儿童)是否患有弱视.Fixation-preference testing has been useful in detecting amb
16、lyopia in children unable to give reliable visual acuities, except for children with small-angle tropias and those without manifest deviations.,斜视儿童注视偏好检查,SFPT 检查方法:将14度垂直三棱镜置于一眼前,从而诱导出垂直斜视.当双眼被分离后, 可以检测出患儿的注视偏好,并用于推测弱视是否存在.By placing a 14-diopter vertical prism over one eye, we induce a vertical deviation. Once the eyes are dissociated, fixation preference is evaluated and used to predict the presence of amblyopia.,
