[技术]Arizona眼睛模型 [复制链接]

简介 (Fq|hgOA>M  
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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。 DQ7+  
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模型 %bo0-lnp  
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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。 mG4myQ?$  
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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. Df;EemCh  
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光源 R?"sM<3`e  
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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。 @UCI^a~w  
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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。 Jy&O4g/'5  
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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。 2E~WcB  
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视网膜的散射 =zw=Jp  
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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。 lej-,HX  
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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。 *?|LE C  
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脚本 o&]b\dV  
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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： N{L'Q0!  
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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。 kev|AU (WX  
余下的脚本计算与屈光度有关的所有参数。 ^0A}iJL  
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分析 (S1c6~  
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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。 (Fc\*Vn  
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脚本代码 B/"TaXVU  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. gDHgXDD_b  
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Dim entity As T_ENTITY 8MIn~  
Dim op As T_OPERATION V_b"^911r  
Dim mat As T_MODELMATERIAL a!UQ]prT  
Dim A As Double GM&< ?K1  
Dim pupilDiam As Double \G}02h  
Dim eID As Long W?y7mw_S  
Dim parID As Long kKbq?}W[  
Dim count As Integer JbT+w\o  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double >R9Q|  
Dim tlens As Double, nlens As Double 50
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Dim curv As Double, conic As Double k'O^HMAn!  
Dim ok As Long =Uy;8et  
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Sub Main m]C|8b7Y  
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    '用户输入对话框 C\%T|ZDE  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 s98Jh(~  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ,1xX`:  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 gcS?r :  
        OKButton 40,91,90,21 ?D 8<}~Do  
        CancelButton 190,91,90,21 kV>[$6  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 @9,=|kxK  
        TextBox 220,49,40,21,.TextBox2 'default: 4 rGa@!^hk  
    End Dialog NC]]`O2r@  
    Dim dlg As UserDialog
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    ok = Dialog (dlg)  :P,g,  
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    If ok=0 Then    'cancel button was pressed e}@VR<h  
        Print "Execution cancelled." \!O3]k,r  
        End :/rl \woA>  
    End If zN3[W`q+m  
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    'Assign accommodation and pupil diameter & use defaults if field left empty dO?zLc0f  
    If dlg.TextBox1 = "" Then /l.:GH36f  
        A = 0           'Default accommodation '3%JhG)#  
    Else ;_$Q~X  
        A = CDbl(dlg.TextBox1) 5OHg%
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    End If }j+Af["W?  
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    If dlg.TextBox2 = "" Then aPU.fER  
        pupilDiam = 4   'Default pupil diameter #%Hk-a=>)#  
    Else -|z ]Ir  
        pupilDiam = CDbl(dlg.TextBox2) ;$a+ >  
    End If KjWF;VN*[3  
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    Print " " C8{bqmlm@  
    Print "Accommodation = " & A & " Diopters" <x!q!;  
    Print "Pupil Diameter = " & pupilDiam & " mm"
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    ' Calculate new parameters with accommodation _sp,,gz  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness vl`Qz"Xy  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens h.Y&_=Gc  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Q,ezAE  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens %*}h{n  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens uBp,_V?  
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    tlens = 3.767 + 0.04*A                  'Lens thickness %IA1Y>`  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction a/\SPXQ/9  
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    'Adjust parameters to account for accommodation -R]Iu\  
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    '************************************************************************* GyC/39<P  
    'Aqueous thickness (Position of Lens) TS_5R>R3  
    '************************************************************************* !1b}M/Wx  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) I`~Giz7@  
    GetCustomElement eID, entity f]pHJVgFV  
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    parID = FindFullName( "Geometry.Arizona Eye" ) lGlh/B%  
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    ' Delete any shift(s) in z o5@d1A  
    count = 0 _ez*dE%  
    While GetOperationCount(eID)>count bI-uF8"  
        GetOperation eID, count, op Ao )\/AR'  
        If op.Type="ShiftZ" Then o&t*[#  
            DeleteOperation eID,count &%UZ"CcA  
            count=count-1 q"48U.}T  
        End If A=Y A#0  
        count=count+1 AqA.
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    Wend NR>&1aRbyb  
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    'Set new shift in dEhFuNO<2  
    op.Type = "ShiftZ" +F
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    op.val1 = taq |EGC1x]j=  
    op.parent = parID
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    AddOperation eID, op Zg*XbX  
    Print "Set aqueous humor thickness = " & taq-0.55 )krBjF.$  
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    '************************************************************************* 8I}
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    'Radius and conic constant of anterior lens .rwa=IW  
    '************************************************************************* {'-^CoR  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) S`Xx('!/|  
    GetConic eID, entity, curv, conic #ZC9=  
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    SetConic eID, entity, 1/Rant, CCant Akdx1h,  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant c(kYCVc   
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    '************************************************************************* OcE,E6LD  
    'Radius and conic constant of posterior lens wX4gy
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    '************************************************************************* dHkI9;  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) {.j030Q  
    GetConic eID, entity, curv, conic 6J]8BHJn+  
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    SetConic eID, entity, 1/Rpost, CCpost ri2`M\;gt  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost uhm3}mWv  

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    '************************************************************************* pkE4"M!3=  
    'Lens thickness (Position of posterior lens surface) P8X59^cJ  
    '************************************************************************* ?orLc,pU^  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) lt("yqBu
 
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    ' Delete any z-shift(s) c :2w(BVi  
    count = 0
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    While GetOperationCount(eID)>count a0jzt!ci  
        GetOperation eID, count, op sd _DG8V  
        If op.Type="ShiftZ" Then  \62!{  
            DeleteOperation eID,count Hva/C{Y  
            count=count-1 "?G?G'yK>  
        End If P#|}]oG%  
        count=count+1 <2e[;$  
    Wend 3Ct:AJeg  
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    'Set new z-shift 4$y P_3  
    op.Type = "ShiftZ" #l 6QE=:  
    op.val1 = tlens [a!)w@I:  
    op.parent = parID 3=("vR`!  
    AddOperation eID, op hs*n?vxp3  
    Print "Set lens thickness = " & tlens :rU,7`sE/  
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    '************************************************************************* \b}%A&Ij  
    'Lens index of refraction A[`2Mnj  
    '************************************************************************* Ki>XLX,er=  
    eID = FindMaterial( "Lens" ) (sSGJS'X  
    GetModelMaterial eID, mat !E6QED"  
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    mat.Nd = nlens '?$R YU,  
    SetModelMaterial eID, mat F+]cFx,/  
    Print "Set lens index of refraction = " & nlens M0t9`Z9  
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    '************************************************************************* /bF>cpM  
    'Pupil diameter G8.nKoHv7x  
    '************************************************************************* ><qA+/4]_  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) aP]h03sS  
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    'Adjust pupil diameter (trimming volume inner hole) TU*Y?D L  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" VV/aec8  
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    ' Adjust pupil location to just in front of the lens )|GYxG;8C  
    parID = FindFullName( "Geometry.Arizona Eye" ) rYM@e  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ~ \b~
 
    count = 0 7#7AK}  
    While GetOperationCount(eID)>count =&)R2pLs*  
        GetOperation eID, count, op kz G W/  
        If op.Type="ShiftZ" Then #itZ~tol  
            DeleteOperation eID,count LKA/s ~G  
            count=count-1 L9]d$ r"  
        End If Z^J7r&\V  
        count=count+1 J$d']%Dwb  
    Wend qYQ vjp  
    op.Type = "ShiftZ" ZcN#jnb0/  
    op.val1 = taq-0.01 rN,T}M=2  
    op.parent = parID  7gx?LI_e  
    AddOperation eID, op a+j"8tHu$  
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    Print "Set pupil diameter = " & pupilDiam 0]zMb^wo  
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    'Update AZ Eye subassembly Description 4HpKKhv"  
    eID = FindFullName( "Geometry.Arizona Eye" ) et/v/Hvw1  
    GetEntity eID, entity yG;@S8zC  
    entity.Description = "Accommodation = " & A & "D" !;Ke#E_d  
    SetEntity eID, entity aMGyV"6(-6  
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    Update h@TP=  
    Print "DONE!" Yy;BJ_  
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End Sub P26"z))~d  
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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： 5}b)W>3@`  
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Accommodation = 4 Diopters u'^kpr`
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Pupil Diameter = 4 mm j<k-w  
Set aqueous humor thickness = 2.81 vpC?JXz=H  
Set anterior lens radius = 10.4 and conic constant = -2.375869 biS{.  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 Y ` Z,52  
Set lens thickness = 3.927 nX\mCO4T  
Set lens index of refraction = 1.42672 R:rols"QM  
Set pupil diameter = 4 X]o"vx%C  
DONE! ]<K"`q2