[技术]Arizona眼睛模型 [复制链接]

简介 ^yRCR] oT  
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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。 b>%I=H%g  
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模型 w9}I*Nra  
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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。 {kJ[)7  
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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. \]J"e%  
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光源 r/Pg,si  
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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。 ^d"tymDd  
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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。 !9o8v0ZI  
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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。 !wrl.A/P  
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视网膜的散射 @V:b Co  
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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。 n?,fF(  
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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。 "<O?KO3K  
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脚本 db%`-UST  
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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： ;pB?8Z  
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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。 OC\C^Yh*U  
余下的脚本计算与屈光度有关的所有参数。 :,VyOmf  
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分析 Ra*9d]N@  
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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。 +vbNZqwz  
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脚本代码 E_yh9lk  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 9Pb0Olh  
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Dim entity As T_ENTITY R\+$^G}#6  
Dim op As T_OPERATION oL6_Ya  
Dim mat As T_MODELMATERIAL gVl#pVO`N  
Dim A As Double Aqm0|GlJ  
Dim pupilDiam As Double Aio0++r-  
Dim eID As Long L]tyL)  
Dim parID As Long T@S+5(  
Dim count As Integer W@0(Y9jdg  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ]JM9 ^F  
Dim tlens As Double, nlens As Double "M*\,IH  
Dim curv As Double, conic As Double 0bd.e
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Dim ok As Long $i`YtV  
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Sub Main FQ4rA 4  
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    '用户输入对话框 k4l72 'P  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7vWB=r>5@  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ><DE1tG  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Gce_gZH7{  
        OKButton 40,91,90,21 [lJ[kr*7  
        CancelButton 190,91,90,21 EagI)W!s[  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 U--ER r8  
        TextBox 220,49,40,21,.TextBox2 'default: 4
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    End Dialog C/$IF M<  
    Dim dlg As UserDialog %$}iM<  
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    ok = Dialog (dlg) BdYh:  
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    If ok=0 Then    'cancel button was pressed bC{~/ JP  
        Print "Execution cancelled." c
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        End qjFgy)qV  
    End If f;Dz(~hw  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 0'<S7?~|  
    If dlg.TextBox1 = "" Then +l#2u#e  
        A = 0           'Default accommodation npF[J x[  
    Else &0"`\~lA  
        A = CDbl(dlg.TextBox1) 4H:WpW*r  
    End If AX
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    If dlg.TextBox2 = "" Then _Dv^~e1c  
        pupilDiam = 4   'Default pupil diameter *SW,pHYnLb  
    Else I@B7uFj  
        pupilDiam = CDbl(dlg.TextBox2) 0Nfj}sXCWE  
    End If B+<k,ad  
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    Print " " L9.#/%I\  
    Print "Accommodation = " & A & " Diopters" 4M]8po/;  
    Print "Pupil Diameter = " & pupilDiam & " mm" JB|I/\(A  
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    ' Calculate new parameters with accommodation We ->d |=  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness x0d+cSw  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens d.Z]R&X08  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens UdGoPzN  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Vt
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    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens {G}HZv%S U  
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    tlens = 3.767 + 0.04*A                  'Lens thickness =T-w.}27O  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 82X.  
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    'Adjust parameters to account for accommodation Trrh`@R  
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    '************************************************************************* P5>CSWy
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    'Aqueous thickness (Position of Lens) tX
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    '************************************************************************* BGX@n#:  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) )hug<D *h  
    GetCustomElement eID, entity |6>_L6t  
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    parID = FindFullName( "Geometry.Arizona Eye" ) F(<8:`N;G  
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    ' Delete any shift(s) in z Bt,Xe~$z-  
    count = 0 &wN 2l-  
    While GetOperationCount(eID)>count K_QCYS.  
        GetOperation eID, count, op $T6Qg(p  
        If op.Type="ShiftZ" Then C~qhwwh  
            DeleteOperation eID,count vgj^-  
            count=count-1 CWp1)%0=  
        End If {ZXC%(u  
        count=count+1 L2'd
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    Wend %7msAvbk  
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    'Set new shift in KeB4Pae|V  
    op.Type = "ShiftZ" )\-";?sYky  
    op.val1 = taq 1v&Fo2ML  
    op.parent = parID vC:b?0s#(  
    AddOperation eID, op 'c&@~O;^d  
    Print "Set aqueous humor thickness = " & taq-0.55 +5[oY,^cO  
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    '************************************************************************* v9U(sEDq  
    'Radius and conic constant of anterior lens %i8>w:@NW  
    '************************************************************************* abeSkWUL(  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) R*Z]  
    GetConic eID, entity, curv, conic rxj@NwAno  
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    SetConic eID, entity, 1/Rant, CCant *ldMr{s<R  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant W@,p9=425  
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    '************************************************************************* vt@Us\fI  
    'Radius and conic constant of posterior lens Q)`gPX3F  
    '************************************************************************* `uh@iD'KI  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) F,M"/hnPT  
    GetConic eID, entity, curv, conic ,6;xr'[o*  
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    SetConic eID, entity, 1/Rpost, CCpost s;2/Nc   
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost (\t_Hs::a  
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    '************************************************************************* ny(GTKoUz  
    'Lens thickness (Position of posterior lens surface) ZQ~myqx,+L  
    '************************************************************************* C$LRY~\  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) rN1U.FRe/
 
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    ' Delete any z-shift(s) q^1aPz  
    count = 0 =+`j?1  
    While GetOperationCount(eID)>count *Z`XG_s5  
        GetOperation eID, count, op g&+Y{*Gp  
        If op.Type="ShiftZ" Then 7q!yCU  
            DeleteOperation eID,count Mf:M3H%YV+  
            count=count-1 sQ}%7BM
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        End If l]Ui@X  
        count=count+1 pSQCT  
    Wend
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    'Set new z-shift jefNiEE[  
    op.Type = "ShiftZ" LMFK3
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    op.val1 = tlens Ty3CBR{6  
    op.parent = parID HX3D*2v":  
    AddOperation eID, op wKk 3)@il  
    Print "Set lens thickness = " & tlens cXS;z.M\_  
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    '************************************************************************* NTm<6Is`  
    'Lens index of refraction CYtjY~  
    '************************************************************************* aGB0-;.t7  
    eID = FindMaterial( "Lens" ) +_ *eu  
    GetModelMaterial eID, mat 4
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    mat.Nd = nlens cgs3qI  
    SetModelMaterial eID, mat Cf0|Z  
    Print "Set lens index of refraction = " & nlens GS ;HtUQ  
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    '************************************************************************* M*5,O
 
    'Pupil diameter 4>4V-m\  
    '************************************************************************* e9CP802#2  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 0A#*4ap  
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    'Adjust pupil diameter (trimming volume inner hole) 7hB#x]oQo  

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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" WD1
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    ' Adjust pupil location to just in front of the lens wgY6D!Y   
    parID = FindFullName( "Geometry.Arizona Eye" )
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    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \un sh^M  
    count = 0 sYGR-:K  
    While GetOperationCount(eID)>count 8y$5oD6g9  
        GetOperation eID, count, op Iq{o-nq  
        If op.Type="ShiftZ" Then O\6vVM[  
            DeleteOperation eID,count -i#J[>=w{C  
            count=count-1 (tepmcf  
        End If NX?}{'f  
        count=count+1 wHx}U M"  
    Wend WFouoXlG0  
    op.Type = "ShiftZ" PPEq6}  
    op.val1 = taq-0.01 jz*0`9&_  
    op.parent = parID BU`ckK
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    AddOperation eID, op xcst<=  
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    Print "Set pupil diameter = " & pupilDiam KYp[Gs  
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    'Update AZ Eye subassembly Description z) :ka"e  
    eID = FindFullName( "Geometry.Arizona Eye" ) IroPx#s:i  
    GetEntity eID, entity cS4DN  
    entity.Description = "Accommodation = " & A & "D" yO00I`5  
    SetEntity eID, entity g0PT8]8  
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    Update 'r\ 4}Ik  
    Print "DONE!" =~&VdPZ  
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End Sub w8p8 ;@  
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如果屈光度是4，光瞳直径是4，则会输出如下数据： #.H}r6jqs  
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Accommodation = 4 Diopters zEj#arSE4  
Pupil Diameter = 4 mm M
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Set aqueous humor thickness = 2.81 [KSH~:h:NR  
Set anterior lens radius = 10.4 and conic constant = -2.375869 nBkh:5E5%  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 A (okv  
Set lens thickness = 3.927 -}P7$|O&  
Set lens index of refraction = 1.42672 _|A+) K  
Set pupil diameter = 4 a7#?h%wf  
DONE! 5pfYEofK[