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    [转载]FRED运用:Arizona眼睛模型 [复制链接]

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    离线xunjigd
     
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    只看楼主 倒序阅读 楼主  发表于: 2016-02-24
    简介 |4mvB2r  
    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。 zz*PAYl.  
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    模型 `2 <:$]  
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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。 4<-Kd~uL  
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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. t.ulG *  
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    光源 'o IE:#b  
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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。 )5b_>Uy  
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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。 } [#8>T  
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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。 MZz9R*_VS  
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    图2. 字母F光源的设定方法光 U(f@zGV  
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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 5b:1+5iF-  
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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。 J,Ki2'=  
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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。 g!~SHW)l  
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    图5. 视网膜重点采样规格设定
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    脚本 G Uu8 N  
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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: =wX;OK|U(^  
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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。 us.[wp'Sh  
    余下的脚本计算与屈光度有关的所有参数。 Kk}, PU=  
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    分析 W$jRS  
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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。 Y)k"KRW+  
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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 ]lA}5  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. =-oP,$k  
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    Dim entity As T_ENTITY _t-6m2A  
    Dim op As T_OPERATION <9&GOaJ  
    Dim mat As T_MODELMATERIAL p|gVIsg[-e  
    Dim A As Double :WWHEZK  
    Dim pupilDiam As Double FZgf"XM>  
    Dim eID As Long ,IhQ%)l  
    Dim parID As Long M;XU"8  
    Dim count As Integer N_ ODr]L  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Vl$RMW@Ds  
    Dim tlens As Double, nlens As Double oPs asa  
    Dim curv As Double, conic As Double iY`[dsT  
    Dim ok As Long RK@K>)"f  
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    Sub Main h*^JFZb  
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        '用户输入对话框 cWnEp';.  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 }'vQUG u8z  
            TextBox 220,21,40,21,.TextBox1 'default: 0 9=}#.W3.  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 1;m?:|6K{  
            OKButton 40,91,90,21 \#biwX  
            CancelButton 190,91,90,21 5 xr2  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 =,*/Ph&  
            TextBox 220,49,40,21,.TextBox2 'default: 4 V #vkj  
        End Dialog yx#!2Z0hw  
        Dim dlg As UserDialog ,8DC9yM,  
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        ok = Dialog (dlg) KOR*y(*8  
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        If ok=0 Then    'cancel button was pressed MA{ZmPm)  
            Print "Execution cancelled." rk %pA-P2  
            End _H U>T  
        End If PM@_ZJ 'x  
    \gT({XU?  
        'Assign accommodation and pupil diameter & use defaults if field left empty _ l)3pm6  
        If dlg.TextBox1 = "" Then Lwtp,.)pR  
            A = 0           'Default accommodation z*VK{O)o  
        Else jKcl{',  
            A = CDbl(dlg.TextBox1) ]hlQU%&  
        End If k3LHLJZ#  
    ;]R5:LbXS  
        If dlg.TextBox2 = "" Then 7lYf+&JZ  
            pupilDiam = 4   'Default pupil diameter  {y{O ze  
        Else ?pQ0* O0  
            pupilDiam = CDbl(dlg.TextBox2) 43=)akJi  
        End If \*5z0A9)5)  
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        Print " " L5:1dF  
        Print "Accommodation = " & A & " Diopters" `E;xI v|  
        Print "Pupil Diameter = " & pupilDiam & " mm" b$Ei>%'/";  
    fM& fqI  
        ' Calculate new parameters with accommodation iqoMQ7%  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 2I suBX\[  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens |pknaz  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens wg k[_i  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens jc32s}/H  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens lV./K;\T  
    )`<&~>qp  
        tlens = 3.767 + 0.04*A                  'Lens thickness RHd no C  
    -jNnx*  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction T#e|{ZCbq  
    !mVq+_7]  
        'Adjust parameters to account for accommodation !gsrPM  
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        '************************************************************************* ]2&RN@  
        'Aqueous thickness (Position of Lens) f6( 1jx"  
        '************************************************************************* wqjR-$c  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) :v45Ls4J  
        GetCustomElement eID, entity ;x FB /,  
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        parID = FindFullName( "Geometry.Arizona Eye" ) {a2Gb  
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        ' Delete any shift(s) in z 9 %Vy,  
        count = 0 19[.&-u"  
        While GetOperationCount(eID)>count Ag{)?5/d_  
            GetOperation eID, count, op H:Q4!<  
            If op.Type="ShiftZ" Then re4z>O*  
                DeleteOperation eID,count :"nh76xg<  
                count=count-1 GAs.?JHd  
            End If :Ez*<;pF'  
            count=count+1 p? w^|V  
        Wend vXM {)  
    3 l j^I  
        'Set new shift in ".pQM.T  
        op.Type = "ShiftZ" x*X{*?5@  
        op.val1 = taq ;Ob^@OM  
        op.parent = parID Ss+  
        AddOperation eID, op [T3%Xt'4  
        Print "Set aqueous humor thickness = " & taq-0.55 dtG>iJ  
    6Xn9$C)  
        '************************************************************************* 8"[{[<-   
        'Radius and conic constant of anterior lens fC}uIci  
        '************************************************************************* "2tKh!?Q  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) {XC[Ia6jtL  
        GetConic eID, entity, curv, conic A&jR-%JG  
    &tiJ=;R1  
        SetConic eID, entity, 1/Rant, CCant XQOM6$~,  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 7pyaHe  
    ZBQ@S  
        '************************************************************************* =<TJ[,h et  
        'Radius and conic constant of posterior lens soLmr's  
        '************************************************************************* ?5% o-hB|  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) XrXW6s ;Z  
        GetConic eID, entity, curv, conic z 63y8  
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        SetConic eID, entity, 1/Rpost, CCpost & \C1QkI  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost yI-EF)A@;  
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        '************************************************************************* zW`a]n.  
        'Lens thickness (Position of posterior lens surface) iJKGzHvS  
        '************************************************************************* Nn?$}g  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) l&Y'5k_R  
    vr6YE;Rs  
        ' Delete any z-shift(s) r&F 6ZCw  
        count = 0 z${[Z=  
        While GetOperationCount(eID)>count u2[L^]|  
            GetOperation eID, count, op g<$2#c}  
            If op.Type="ShiftZ" Then 0<f.r~  
                DeleteOperation eID,count _ib @<%  
                count=count-1 "kVzN22  
            End If |v 1* [(  
            count=count+1 v5{2hCdt  
        Wend Bob-qCBV  
    F]0 qt$GO  
        'Set new z-shift &xt GabNk  
        op.Type = "ShiftZ" Jy('tfAHp  
        op.val1 = tlens ]9W7]$  
        op.parent = parID rJRg4Rog  
        AddOperation eID, op P%!=Rj^2m  
        Print "Set lens thickness = " & tlens PY+4OZ$  
    V&Rwj_Y  
        '************************************************************************* 43O5|8o  
        'Lens index of refraction 1FT3d  
        '************************************************************************* `'pAiu  
        eID = FindMaterial( "Lens" ) -]n%+,3L  
        GetModelMaterial eID, mat uZI7,t-7  
    {&6i$4T  
        mat.Nd = nlens G9GLRdP  
        SetModelMaterial eID, mat % w  
        Print "Set lens index of refraction = " & nlens /fAAQ7  
    $>+g)  
        '************************************************************************* }O| 9Qb  
        'Pupil diameter MGr e_=Dm_  
        '************************************************************************* (<e<Q~(  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) i1bmUKZ8'L  
    *O_^C  
        'Adjust pupil diameter (trimming volume inner hole) Jz P0D'  
    )V_;]9<wt  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" _,d<9 Y)  
    C46jVl   
        ' Adjust pupil location to just in front of the lens \F""G,AWq{  
        parID = FindFullName( "Geometry.Arizona Eye" ) hMV>5Y[s  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) dT (i*E\j  
        count = 0 !?+q7U  
        While GetOperationCount(eID)>count ~-R2mAUK  
            GetOperation eID, count, op !aL=R)G&e  
            If op.Type="ShiftZ" Then <vD(,||  
                DeleteOperation eID,count p(Osz7K  
                count=count-1 |f.,fVVV;  
            End If h@y>QhYU0  
            count=count+1 (=EDqAZg  
        Wend ~03MH'  
        op.Type = "ShiftZ" :-$8u;!M  
        op.val1 = taq-0.01 t% <y^Wa=  
        op.parent = parID es=OWJt^  
        AddOperation eID, op (vvD<S*  
    :fq4oHA#  
        Print "Set pupil diameter = " & pupilDiam  _-9cGm v  
    )+w1nw|m  
        'Update AZ Eye subassembly Description 6E9/ z  
        eID = FindFullName( "Geometry.Arizona Eye" ) 8B5WbS fL^  
        GetEntity eID, entity k,f/9e+#  
        entity.Description = "Accommodation = " & A & "D" gFT lP  
        SetEntity eID, entity uU^iY$w  
    y*v|q=  
        Update !ab ef.%:  
        Print "DONE!" HPJHA ,  
         mZjpPlJ  
    End Sub Zj1bG{G=i  
    Z&P\}mm   
    如果屈光度是4,光瞳直径是4,则会输出如下数据: ,|.}6\zl*{  
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    Accommodation = 4 Diopters ='m%Iq7X  
    Pupil Diameter = 4 mm e0otr_)3F  
    Set aqueous humor thickness = 2.81 #N'9 w .  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 %O<8H7e)V  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 ?,8+1"|$A]  
    Set lens thickness = 3.927 U~;tk@  
    Set lens index of refraction = 1.42672 a ~W  
    Set pupil diameter = 4 $$"G1<EZ  
    DONE! Kr `/sWZ  
    ;[(d=6{hc]  
    (文章来源:讯技光电)
     
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