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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 ^@`dsll  
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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。 MqI!i>  
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模型 @Tzh3,F2  
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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。 F/}PN1#T  
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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. nQvv'%v0   
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光源 y_8 8I:O  
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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。 4>>d "<}C  
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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。 !K1[o'o#  
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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。 U w][U  
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图2. 字母F光源的设定方法光 ^'C1VQ%  
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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 'zZN]P  
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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。 i}+K;,Da:8  
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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。 b4s.`%U  
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图5. 视网膜重点采样规格设定
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脚本 7 rOziKZ"  
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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: u-At k-2M  
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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。 r+;op_  
余下的脚本计算与屈光度有关的所有参数。 DnP>ed"M!  
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分析 TP[<u-@G  
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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。 @]t}bF]  
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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 NB;8 e>8  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. u!];RHOp|  
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Dim entity As T_ENTITY l_y:IY$"  
Dim op As T_OPERATION Z~ VOO7|m  
Dim mat As T_MODELMATERIAL k/?5Fs!#  
Dim A As Double Mk7,:S  
Dim pupilDiam As Double mTT1,|  
Dim eID As Long pM= @  
Dim parID As Long ds,NNN<HW  
Dim count As Integer G< l+94(  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double hMh8)S  
Dim tlens As Double, nlens As Double iF?4G^  
Dim curv As Double, conic As Double o nt8q8  
Dim ok As Long & xo,49`!  
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Sub Main nxkbI:+t  
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    '用户输入对话框 1WRQjT=o  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 *Fb]lM7D  
        TextBox 220,21,40,21,.TextBox1 'default: 0 j BS$xW  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 }9<pLk  
        OKButton 40,91,90,21 9}p?h1NrY  
        CancelButton 190,91,90,21 d`q<!qFZh  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 *JDQaWzBd  
        TextBox 220,49,40,21,.TextBox2 'default: 4 gE]6]L  
    End Dialog > L_kSC?  
    Dim dlg As UserDialog c! vtQ<h-  
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    ok = Dialog (dlg) zgXg-cr  
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    If ok=0 Then    'cancel button was pressed mZQW>A]iE  
        Print "Execution cancelled." N"1o> !  
        End :jlKj}4A  
    End If ul$k xc=N  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 4u- mE  
    If dlg.TextBox1 = "" Then $5N%!  
        A = 0           'Default accommodation mQdF+b1o  
    Else r#rL~Rsd}  
        A = CDbl(dlg.TextBox1) .\XFhOsa  
    End If gb+iy$o-  
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    If dlg.TextBox2 = "" Then Z" j #kaXA  
        pupilDiam = 4   'Default pupil diameter f?vbIc`  
    Else R8LJC]6Bh  
        pupilDiam = CDbl(dlg.TextBox2) ,Ta k',  
    End If  @oE^(  
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    Print " " E><$sN6  
    Print "Accommodation = " & A & " Diopters" nSY3=Edx=  
    Print "Pupil Diameter = " & pupilDiam & " mm" c\A 4-08  
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    ' Calculate new parameters with accommodation UMtnb:ek  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness gQ90>P:  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens x*>@knP<-  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens OlRtVp1  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 4JQd/;  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens (;\" K?  
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    tlens = 3.767 + 0.04*A                  'Lens thickness \Lu aI  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction R !&9RvNw  
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    'Adjust parameters to account for accommodation xqm-m  
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    '************************************************************************* "&Q sv-9t  
    'Aqueous thickness (Position of Lens) 7R5m|h`M  
    '************************************************************************* r2ZSkP.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) F8xz^UQO  
    GetCustomElement eID, entity Hk&op P9)  
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    parID = FindFullName( "Geometry.Arizona Eye" ) l4Au{%j\  
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    ' Delete any shift(s) in z Ei>.eXUD5  
    count = 0 P^(uS'j)+  
    While GetOperationCount(eID)>count &{4KymB:  
        GetOperation eID, count, op Cb4.N 8  
        If op.Type="ShiftZ" Then 88x2Hf5I  
            DeleteOperation eID,count fQm3D%  
            count=count-1 [0bp1S~  
        End If z}BuR*WSY{  
        count=count+1 +{~ cX] |  
    Wend B:)PUBb  
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    'Set new shift in tt&#4Z  
    op.Type = "ShiftZ" H 0( .p'eN  
    op.val1 = taq xig4H7V  
    op.parent = parID f;D(X/"f]  
    AddOperation eID, op hZIbN9)8A  
    Print "Set aqueous humor thickness = " & taq-0.55 JUXo3D~  
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    '************************************************************************* FPb4VJ|xm  
    'Radius and conic constant of anterior lens =W*Ro+wWb  
    '************************************************************************* _xsHU`(J#  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) &?@gCVNO,  
    GetConic eID, entity, curv, conic ''^2rF^  
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    SetConic eID, entity, 1/Rant, CCant Y sDai<  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant !L[$t~z  
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    '************************************************************************* B/Js>R  
    'Radius and conic constant of posterior lens ~@#s<a,%;  
    '************************************************************************* GX+Gqj.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) \J(kevX  
    GetConic eID, entity, curv, conic lb{X6_.  
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    SetConic eID, entity, 1/Rpost, CCpost w-];!;%  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost y@h v#;  
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    '************************************************************************* Ts\PZQ!q  
    'Lens thickness (Position of posterior lens surface) fBb:J+  
    '************************************************************************* (fYYcpd,k  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) v4qpE!W27~  
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    ' Delete any z-shift(s) v4]#Nc$~T  
    count = 0 ], IQ~  
    While GetOperationCount(eID)>count /2Z7  
        GetOperation eID, count, op %x./>-[t  
        If op.Type="ShiftZ" Then C).+h7{nd  
            DeleteOperation eID,count PYwGGB-  
            count=count-1 xyP 0haE  
        End If x"7PnN|~  
        count=count+1 *:% I|5  
    Wend >]HvXEdNZ|  
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    'Set new z-shift ai<K6)  
    op.Type = "ShiftZ" dy~M5,zn  
    op.val1 = tlens wE -y4V e  
    op.parent = parID 4~AY: ib|  
    AddOperation eID, op +y_V$q$G  
    Print "Set lens thickness = " & tlens KBoW(OP4'  
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    '************************************************************************* Xyu0n p;@  
    'Lens index of refraction ]|N"jr?7H  
    '************************************************************************* peew <SX  
    eID = FindMaterial( "Lens" ) Y>{%,d#s_  
    GetModelMaterial eID, mat `46|VQAx  
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    mat.Nd = nlens 6FX]b4  
    SetModelMaterial eID, mat qYPgn _  
    Print "Set lens index of refraction = " & nlens >[N6_*K]  
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    '************************************************************************* *'BI=* `  
    'Pupil diameter .zy2_3:  
    '************************************************************************* sZwa#CQKq  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) VVEJE$  
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    'Adjust pupil diameter (trimming volume inner hole) -M+o;  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" "AlR%:]24~  
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    ' Adjust pupil location to just in front of the lens 7CCSG{k  
    parID = FindFullName( "Geometry.Arizona Eye" ) S^N{=*  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) BwYR"  
    count = 0 l}FA&c"  
    While GetOperationCount(eID)>count x&N@R?AG1  
        GetOperation eID, count, op 29W`L2L  
        If op.Type="ShiftZ" Then x}f)P  
            DeleteOperation eID,count ti<;>P[4  
            count=count-1 !-7<x"avm  
        End If OTEx9  
        count=count+1 'N&s$XB,  
    Wend BA9;=orx  
    op.Type = "ShiftZ" Qqd+=mgc  
    op.val1 = taq-0.01 SwO8d;e  
    op.parent = parID BPy pA $  
    AddOperation eID, op Kww+lgzS  
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    Print "Set pupil diameter = " & pupilDiam ?U,XyxN  
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    'Update AZ Eye subassembly Description wh3Wuh?x  
    eID = FindFullName( "Geometry.Arizona Eye" ) C?rb}(m  
    GetEntity eID, entity -}5dZ;  
    entity.Description = "Accommodation = " & A & "D" m.U&O=]5  
    SetEntity eID, entity 'l1cuAP!+  
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    Update `)H| &!wT  
    Print "DONE!" ]2z Gb5s"  
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End Sub Tt{ft?H71  
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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: =Q8$O 2TW  
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Accommodation = 4 Diopters \qbEC.-K  
Pupil Diameter = 4 mm ra]\!;}L0  
Set aqueous humor thickness = 2.81 s=XqI@  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ibgF,N  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 +s5Yg,4*  
Set lens thickness = 3.927 ZQ~EaI9R  
Set lens index of refraction = 1.42672 h-@_.&P0e  
Set pupil diameter = 4 l 4cTN @E  
DONE! s`L>mRw`  
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