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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 v; &-]ka  
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人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 aj|I[65  
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模型 7M=`Z{=9  
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模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 ]fnc.^{  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. 7%&#V2  
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光源 w8%<O^wN,  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 g3Xq@RAJc  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 cAC]%~orx  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 Z455g/=ye  
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图2. 字母F光源的设定方法光 hdXdz aNS  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 g0: mm,t\  
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在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 =EA*h_"q9  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 1(CpTaa  
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图5. 视网膜重点采样规格设定
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脚本 -R?~Yysd7K  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: PO%Z.ol9  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 "94e-Nx  
余下的脚本计算与屈光度有关的所有参数。 swss#?.se  
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分析 0 XxU1w8\V  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 .DR^<Qy  
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图7. 字母F在视网膜上颜色分析
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脚本代码 52 ? TLID  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 2Z;wU]  
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Dim entity As T_ENTITY TPEg>[  
Dim op As T_OPERATION KSe `G;{  
Dim mat As T_MODELMATERIAL TUuw  
Dim A As Double q,w8ca 4~y  
Dim pupilDiam As Double owM3Gz%?UA  
Dim eID As Long 9y"R,  
Dim parID As Long wqEO+7)S  
Dim count As Integer N/IDj2C4  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double sOQF_X(.x  
Dim tlens As Double, nlens As Double cy T,tN  
Dim curv As Double, conic As Double n]c6nX:'  
Dim ok As Long <Yif-9  
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Sub Main X%w`:c&  
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    '用户输入对话框 xXkP(^ Y  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 fn(< <FA)  
        TextBox 220,21,40,21,.TextBox1 'default: 0 /qM:;:N%j  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 @AET.qGC  
        OKButton 40,91,90,21 LE#ko2#ke  
        CancelButton 190,91,90,21 -]HPDN,OB  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 fl%X>\i/7  
        TextBox 220,49,40,21,.TextBox2 'default: 4 k@vN_Un  
    End Dialog 0wL-Ak#v  
    Dim dlg As UserDialog l-4+{6lz  
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    ok = Dialog (dlg) GxjmHo  
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    If ok=0 Then    'cancel button was pressed UolsF-U}'  
        Print "Execution cancelled." R{={7.As+  
        End O_-Lm4g?4  
    End If {6}H}_( ]  
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    'Assign accommodation and pupil diameter & use defaults if field left empty )lB 3U  
    If dlg.TextBox1 = "" Then 3jH-!M5  
        A = 0           'Default accommodation {-?^j{O0.  
    Else +$_.${uwV  
        A = CDbl(dlg.TextBox1) b7;`A~{9v  
    End If ;;|S QX  
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    If dlg.TextBox2 = "" Then #Xdj:T<*  
        pupilDiam = 4   'Default pupil diameter 4I&e_b< 30  
    Else +Wgp~$o4  
        pupilDiam = CDbl(dlg.TextBox2) i b$2qy  
    End If e0rh~@E  
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    Print " " =Rv!c+?  
    Print "Accommodation = " & A & " Diopters" 9&]g2iT P  
    Print "Pupil Diameter = " & pupilDiam & " mm" Z]VmTB  
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    ' Calculate new parameters with accommodation G_m$W3 zS  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness W_JFe(=3,  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens Lmp_8q-Ej  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens *SP@`)\D  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens RQg7vv]%  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens G%Dhj)2}  
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    tlens = 3.767 + 0.04*A                  'Lens thickness =H8 LBM  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Wra$  
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    'Adjust parameters to account for accommodation w^/jlddF  
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    '************************************************************************* cZVVJUF  
    'Aqueous thickness (Position of Lens) coG_bX?e  
    '************************************************************************* {`KRr:w  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) vZ0K1UTEXY  
    GetCustomElement eID, entity ]?1n-w.}r  
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    parID = FindFullName( "Geometry.Arizona Eye" ) 4nvi7  
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    ' Delete any shift(s) in z #gQaNc?  
    count = 0 ~d.Z. AD  
    While GetOperationCount(eID)>count K*"Wq:T;B  
        GetOperation eID, count, op TAE@KSPvo  
        If op.Type="ShiftZ" Then qG&}lg?g{  
            DeleteOperation eID,count ()\=(n!J  
            count=count-1 !Au@\/}  
        End If =#z8CFq[O  
        count=count+1 JA <Hm.V#  
    Wend igGg[I1?  
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    'Set new shift in *i`t4N A  
    op.Type = "ShiftZ" ,JU3 w  
    op.val1 = taq :U{$G( <  
    op.parent = parID AP:(/@K|  
    AddOperation eID, op t5M"M{V  
    Print "Set aqueous humor thickness = " & taq-0.55 AJJa<c+j  
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    '************************************************************************* 9| {t%F=-  
    'Radius and conic constant of anterior lens &%=]lP]  
    '************************************************************************* 1*VArr6*6  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 7A=*3  
    GetConic eID, entity, curv, conic 4S 7#B  
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    SetConic eID, entity, 1/Rant, CCant ag* 5fBF  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant C{<dzooz  
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    '************************************************************************* E&_q"jJRi  
    'Radius and conic constant of posterior lens <0h,{28  
    '************************************************************************* # 9@K  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) b;2[E/JKB  
    GetConic eID, entity, curv, conic iTu~Y<'m  
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    SetConic eID, entity, 1/Rpost, CCpost 4))5l9kc.  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 1Z_2s2`p  
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    '************************************************************************* !8@8  
    'Lens thickness (Position of posterior lens surface) /h v2=A  
    '************************************************************************* \b6vu^;p  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) \&,{N_G#L.  
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    ' Delete any z-shift(s) }Nc Ed;  
    count = 0 z[?&bF<|  
    While GetOperationCount(eID)>count :< *xG&  
        GetOperation eID, count, op IW$qP&a  
        If op.Type="ShiftZ" Then  JE=3V^k  
            DeleteOperation eID,count o ?`LZd:{  
            count=count-1 m2j]wUh"  
        End If k"pN  
        count=count+1 y8Oz4|  
    Wend g}gOAN3.  
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    'Set new z-shift >ca w :  
    op.Type = "ShiftZ" QTmMj@R&(  
    op.val1 = tlens LKsK!X  
    op.parent = parID +zINnX  
    AddOperation eID, op E06)&tF  
    Print "Set lens thickness = " & tlens w^=uq3X?  
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    '************************************************************************* Y$<p_X,  
    'Lens index of refraction pzFM#   
    '************************************************************************* >^bSjE  
    eID = FindMaterial( "Lens" ) :7L[v9'  
    GetModelMaterial eID, mat r=Od%  
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    mat.Nd = nlens Dk#4^`qp1  
    SetModelMaterial eID, mat }Q-%ij2  
    Print "Set lens index of refraction = " & nlens i0g/'ZP  
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    '************************************************************************* iL8:I)z  
    'Pupil diameter & oj$h  
    '************************************************************************* )n{9*{Ch  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) NhRKP"<CO  
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    'Adjust pupil diameter (trimming volume inner hole) iNG =x   
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" c-`izn]  
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    ' Adjust pupil location to just in front of the lens ]\6*2E{1m  
    parID = FindFullName( "Geometry.Arizona Eye" ) K [R.B!;N  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 0fAo&B  
    count = 0 "YoFUfaNg  
    While GetOperationCount(eID)>count !D~\uW1b  
        GetOperation eID, count, op ,#8H9<O9t  
        If op.Type="ShiftZ" Then Lj Y@b  
            DeleteOperation eID,count  hpOK9  
            count=count-1 :S=!]la0h  
        End If V1 {'d[E*  
        count=count+1 D22jWm2  
    Wend A(T=  
    op.Type = "ShiftZ" ~^v*f   
    op.val1 = taq-0.01 Ur,{ZGm  
    op.parent = parID KF}_|~~T  
    AddOperation eID, op &]jCoBj+_  
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    Print "Set pupil diameter = " & pupilDiam PD`EtkUnv  
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    'Update AZ Eye subassembly Description !I+F8p   
    eID = FindFullName( "Geometry.Arizona Eye" ) .s`7n *xz  
    GetEntity eID, entity t`G<}t  
    entity.Description = "Accommodation = " & A & "D" EE,C@d!*k7  
    SetEntity eID, entity >gZ"^iW  
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    Update [WN2ZQ  
    Print "DONE!" x%OJ3Qjj=  
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End Sub 6bd{3@   
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如果屈光度是4,光瞳直径是4,则会输出如下数据: [5wU0~>'  
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Accommodation = 4 Diopters *$9Rb2}kK  
Pupil Diameter = 4 mm ,Lr}P  
Set aqueous humor thickness = 2.81 F:'>zB]-}  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ~NB lJULS  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 z2god 1"  
Set lens thickness = 3.927 Pw/$ }Q9X  
Set lens index of refraction = 1.42672 4{#0ci{  
Set pupil diameter = 4 t[%ELHV  
DONE! g#r,u5<*?  
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