屈光不正课件

为了便于分析眼的成像和计算，人们常用 Gullstrand精密模型眼和Gullstrand简易模 型眼，后者将眼球复杂的多个光学界面简化 ，其特点是将角膜简化为单一球面和晶状体 简化为前后两个面。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
人眼的屈光状态受到多种因素的影响，包括遗传 因素和环境因素。正常情况下，婴幼儿出生不久 大部分都是处于远视状态，随着生长发育，逐渐 趋于正视，至学龄前基本达到正视，该过程称为 “正视化”。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
外界所要注视的物体，通过眼的光学系统折 射后聚焦在视网膜上，是人们获得清晰视觉 的前提。若在眼调节放松的状态下，无穷远 处物体所成的像没有准确聚焦在视网膜上， 即称为“屈光不正”；而此时若正好聚焦在 视网膜上，则称为“正视”。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
眼所能产生的最大调节称为调节幅度，与年龄密 切相关。青少年调节力强，随着年龄增长，调节 力将逐渐减退而出现老视。
临床上比较常应用Hoffstetter调节幅度公式来表 达调节力与年龄的关系： 最小调节幅度= 15-0.25 ×年龄 最大调节幅度= 25-0.4×年龄 平均调节幅度= 18-0.3 ×年龄
眼视光学简介
衡阳爱尔 李康
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
眼球的光学系统成分 由外向内为角膜、房 水、晶状体和玻璃体。
Байду номын сангаас
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
第二节 眼球光学
当光从一种介质进入另一种不同折射率的介质时， 光线将在界面发生偏折现象，该现象在眼球光学 中称为屈光（refraction)。光线在界面的偏折程 度，可用屈光力来表达。
在眼球光学中，应用屈光度（diopter,D)作为屈 光力的单位。屈光度为焦距的倒数，即D=1/f。 如一透镜的焦距为0.5m，则该透镜的屈光力为： 1/0.5=2.00D。
调节范围(accommodative range) 眼在调节放松状态下所能看清的最远一点 称为远点。眼在极度调节时所能看清的最 近一点称为近点。远点和近点之间的距离 为调节范围。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
二、近视(myopia) 在调节放松状态下，平行光线经眼球屈光系统后聚焦在视
调节、集合与瞳孔反应 产生调节的同时引起双眼内 转，该现象称为集合。调节 越大集合也越大，调节和集 合是一个联动过程，两者保 持协同关系。表达集合程度 常用棱镜度。 调节时还将发生瞳孔缩小。 因此调节、集合和瞳孔缩小 为眼的三联动现象。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
第三节 正视、屈光不正与老视 一、正 视
当眼调节静止时，外界的平行 光线（一般认为来自5m以外）经 眼的屈光系统恰好在视网膜黄斑中 心凹聚焦，这种屈光状态称为正视 （emmetropia）。若不能在视网膜黄斑中心凹聚焦，将不能产
生清晰像，称为非正视或屈光不正(refractive error)。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
屈光不正的状态比较复杂，主要包括近视、远 视、散光等。老视（亦称老花）虽然是因年龄 而出现的生理性调节问题所致，也常常被归为 “屈光不正”的一种特殊类型。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
眼的调节与集合 调节 ：为看清目标，需增加晶状体的曲率，从而
增强眼的屈光力，使近距物体在视网膜上形成清 晰的像，这种为看清近距物而改变眼的屈光力的 功能称为调节（accommodation)。
As the only big agricultural village in Tianding Township, some achievements have been made through the beneficial exploration of villagers' autonomy in family planning for more than a y ear.
通常认为调节产生的机理是：当看远目标时，睫状肌处于 松弛状态，睫状肌使晶状体悬韧带保持一定的张力，晶状 体在悬韧带的牵引下，其形状相对扁平；当看近目标时， 环形睫状肌收缩，睫状冠所形成的环缩小，晶状体悬韧带 松弛，晶状体由于弹性而变凸。