[技术]Arizona眼睛模型 [复制链接]

简介 2KVMQH`B9  
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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。 mqgA  
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模型 fkE4[X7f  
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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。 edld(/wu~  
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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. =ic"K6mhq  
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光源 Dyv 6K_,  
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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。 @igGfYy  
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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。 C9zQ{G  
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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。 r&sm&4)p-5  
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视网膜的散射 _mVq9nBEf  
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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(TG  
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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。 {n9]ej^  
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脚本 ,b;eU[!]  
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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： 5dc24GB>_  
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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。
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余下的脚本计算与屈光度有关的所有参数。 *L_+rJj,  
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分析 7A0D[?^xe  
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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。 Cv7FVl-I  
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脚本代码 bxX[$q  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. / J 3  
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Dim entity As T_ENTITY .)Xyzd  
Dim op As T_OPERATION c(Liwuj  
Dim mat As T_MODELMATERIAL y9W6e"  
Dim A As Double b0W~*s [4  
Dim pupilDiam As Double +$Q.N{LV  
Dim eID As Long Y rq-(  
Dim parID As Long S!
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Dim count As Integer ap|7./yg  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Y r3h=XY  
Dim tlens As Double, nlens As Double W vh3Y,|3  
Dim curv As Double, conic As Double Q}ebw
 
Dim ok As Long >y&Db  
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Sub Main s;oDwT1  
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    '用户输入对话框 -h=K]Y{`  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _@U?;73"5  
        TextBox 220,21,40,21,.TextBox1 'default: 0 vrVb/hhG  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 :N!Fe7H,  
        OKButton 40,91,90,21 *n9t~t6GHg  
        CancelButton 190,91,90,21 q2Xm~uN`)  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 $
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        TextBox 220,49,40,21,.TextBox2 'default: 4  P%#WeQ+  
    End Dialog Pl|e?Np  
    Dim dlg As UserDialog ;O7CahdF  
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    ok = Dialog (dlg) R7~H}>uaF  
}
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    If ok=0 Then    'cancel button was pressed Jpi\n- d!  
        Print "Execution cancelled." #H]cb#  
        End A2Je*Gz  
    End If Y@)iPK@z  
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    'Assign accommodation and pupil diameter & use defaults if field left empty ?.E ixGzI^  
    If dlg.TextBox1 = "" Then _TF\y@hF*D  
        A = 0           'Default accommodation ;dXQB>Za  
    Else 5AmYrXZ  
        A = CDbl(dlg.TextBox1) 7;cb^fi/  
    End If l=(4o4um  
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    If dlg.TextBox2 = "" Then 4VtI8f!  
        pupilDiam = 4   'Default pupil diameter ?6h65GO{  
    Else Jjt'R`t%t  
        pupilDiam = CDbl(dlg.TextBox2) G2#={g{  
    End If CV/ei,=9  
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    Print " " 4F_*,
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    Print "Accommodation = " & A & " Diopters" j$Tto
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    Print "Pupil Diameter = " & pupilDiam & " mm" T KpX]H`  
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    ' Calculate new parameters with accommodation ]{->/.oB  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness j3j<01rq  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 3+6s}u)
 
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens D{hsa  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ~*-(_<FH  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens PoyY}Ra  
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    tlens = 3.767 + 0.04*A                  'Lens thickness F Qtlo+3  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 9f ,$JjX[  
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    'Adjust parameters to account for accommodation 2qEm,x'S  
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    '************************************************************************* sflH{!;p  
    'Aqueous thickness (Position of Lens) Wj2s+L7,  
    '************************************************************************* \x JGR!  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) BMlnzi  
    GetCustomElement eID, entity yya"*]*S  
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    parID = FindFullName( "Geometry.Arizona Eye" ) y%.^| G  
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    ' Delete any shift(s) in z g'G"`)~ 2  
    count = 0 IipG?v0z~  
    While GetOperationCount(eID)>count YGy.39@31  
        GetOperation eID, count, op *b+ef  
        If op.Type="ShiftZ" Then /[f9Z:>V  
            DeleteOperation eID,count ?yKW^,q+  
            count=count-1 Xo[={2_  
        End If n W2[x;  
        count=count+1 g70B22!y  
    Wend ve|:z  
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    'Set new shift in /A3tY"Vn  
    op.Type = "ShiftZ" jkd'2  
    op.val1 = taq +bwSu)k  
    op.parent = parID Hm=!;xAFX  
    AddOperation eID, op 0pP;[7k\  
    Print "Set aqueous humor thickness = " & taq-0.55
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    '************************************************************************* 2BA'Zu`  
    'Radius and conic constant of anterior lens m'h`%0Tc  
    '************************************************************************* T;(k  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) h+o-h4X  
    GetConic eID, entity, curv, conic _~m@ SI  
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    SetConic eID, entity, 1/Rant, CCant R +H0+omj  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant <ptZY.8N  
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    '************************************************************************* <uUHr,#  
    'Radius and conic constant of posterior lens
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    '************************************************************************* > %5<fK2  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) uW*)B_
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    GetConic eID, entity, curv, conic 8^26g3  
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    SetConic eID, entity, 1/Rpost, CCpost tuzw%=Ey  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ,k}-I65M*t  
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    '************************************************************************* rt+%&%wt  
    'Lens thickness (Position of posterior lens surface) XV"8R"u%Q  
    '*************************************************************************  5VWyc9Q  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" )  b,]QfC  
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    ' Delete any z-shift(s) KiN8N=
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    count = 0 "F nH>g-  
    While GetOperationCount(eID)>count Y%AVC9(  
        GetOperation eID, count, op ,DUD4 [3  
        If op.Type="ShiftZ" Then fi*@m,-  
            DeleteOperation eID,count F91'5D,u0  
            count=count-1 Wr.G9zq.+  
        End If eH.~c3o  
        count=count+1 R"NR-iU  
    Wend &s.S)'l4l  
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    'Set new z-shift ZzZy2.7  
    op.Type = "ShiftZ" .W[ 9G\  
    op.val1 = tlens L4bx [  
    op.parent = parID ~gz_4gzb  
    AddOperation eID, op K0hmRR=  
    Print "Set lens thickness = " & tlens |G^w2"D_Z  
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    '************************************************************************* p*F.WxB)4  
    'Lens index of refraction  xY]Y  
    '************************************************************************* B}n tD  
    eID = FindMaterial( "Lens" ) 7[=MgnmuC  
    GetModelMaterial eID, mat QDO.
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    mat.Nd = nlens : b9X?%L~  
    SetModelMaterial eID, mat [I*zZ`  
    Print "Set lens index of refraction = " & nlens 0q6$KP}q  
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    '************************************************************************* q~QB?+ x&  
    'Pupil diameter m0*bz5  
    '************************************************************************* 7f!"vhCXM;  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) v<+5B5"1  
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    'Adjust pupil diameter (trimming volume inner hole) H{Fww4pn  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" NGsG4y^g?z  
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    ' Adjust pupil location to just in front of the lens S6~&g|T,  
    parID = FindFullName( "Geometry.Arizona Eye" ) i7N|p9O.  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) g<ZB9;FX %  
    count = 0 :xd)]Ns  
    While GetOperationCount(eID)>count yHrYSE
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        GetOperation eID, count, op eiTG  
        If op.Type="ShiftZ" Then *qM)[XO  
            DeleteOperation eID,count oT=XCa5  
            count=count-1 ){~]-VK  
        End If >x/;'Y.  
        count=count+1 Pe-1o#7~W  
    Wend 1?6zsA%N  
    op.Type = "ShiftZ" 'Ipp1a Z_M  
    op.val1 = taq-0.01 nQy%av$  
    op.parent = parID o*\Fj}l-  
    AddOperation eID, op <$H-/~Y  
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    Print "Set pupil diameter = " & pupilDiam %3ieR}:/e&  
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    'Update AZ Eye subassembly Description 2<"kfan  
    eID = FindFullName( "Geometry.Arizona Eye" ) jv<C#0E^  
    GetEntity eID, entity 6;JlA})  
    entity.Description = "Accommodation = " & A & "D" aaa6R|>0  
    SetEntity eID, entity _VvXE572  
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    Update ~Vh< mt  
    Print "DONE!" *Fb|iR  
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End Sub B<et&r;  
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如果屈光度是4，光瞳直径是4，则会输出如下数据： [\41  
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Accommodation = 4 Diopters Hu4\4x$?  
Pupil Diameter = 4 mm a,>`ab%>  
Set aqueous humor thickness = 2.81 ;|a,1#x  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ;s$bVGHr  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 Imv]V6"D=  
Set lens thickness = 3.927 oM<Y o%n  
Set lens index of refraction = 1.42672 ^nPk;%`0  
Set pupil diameter = 4 f_{OU E  
DONE! *_Sx^`"X`l