AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.眼视光学简介眼视光学简介眼视光学简介眼视光学简介衡阳爱尔李康AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.第一节概述第一节概述眼是以光作为适宜刺激的视觉生物器官，因此从光学角度可将眼看作一种光学器具，即一种复合光学系统。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.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。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.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”。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.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。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.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”。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.第二节眼球光学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。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.眼球总屈光力(totaldiopteroftheeyeball)在调节静止状态下为58.64D。眼屈光系统中最主要的屈光成分是角膜和晶状体，角膜的屈光力大约为43D，晶体约为19D。眼轴长度24mm。（数据来自人卫7版眼科学）AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.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。AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebeneficialexplorationofvillagers'autonomyinfamilyplanningformorethanayear.AstheonlybigagriculturalvillageinTiandingTownship,someachievementshavebeenmadethroughthebene...
