[转载]FRED运用：Arizona眼睛模型 [复制链接]

简介 9b8kRz[ c  
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。 K F:W:8  
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模型 "1-|ahW  
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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。 o:.6{+|N  
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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. RfZZqeU  
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光源 pYtvenBy  
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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。 B <CK~ybY  
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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。 !Q0aKkMfL  
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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。 Yw\7`  
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视网膜的散射 w|;kL{(W  
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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。 EE^ N01<"\  
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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。 3XOf-v:~  
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脚本 rl<!h5  
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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： ub#>kCL9  
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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。 e/h2E dY  
余下的脚本计算与屈光度有关的所有参数。 ?]d[K>bv  
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分析 :=<0Z1S  
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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。 :N3'$M"  
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脚本代码 K~?M?sa  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. _QhB0/C  
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Dim entity As T_ENTITY GmA5E  
Dim op As T_OPERATION LPOZA`  
Dim mat As T_MODELMATERIAL *@C4~Zo  
Dim A As Double WLb*\  
Dim pupilDiam As Double NWGSUUa  
Dim eID As Long =Wl*.%1 b  
Dim parID As Long ~4{E0om@  
Dim count As Integer g;>M{)A  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double m^
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Dim tlens As Double, nlens As Double #2F 6}  
Dim curv As Double, conic As Double |?t6h 5Mt"  
Dim ok As Long =h083|y>  
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Sub Main 0'DlsC/`*  
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    '用户输入对话框 +dkbt%7M  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 A5lP%&tu(  
        TextBox 220,21,40,21,.TextBox1 'default: 0 bEXm@-ou  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Wgh4DhAW  
        OKButton 40,91,90,21 %7_c|G1  
        CancelButton 190,91,90,21 .CrrjS w  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 wGqQR)a  
        TextBox 220,49,40,21,.TextBox2 'default: 4 >gt_C'  
    End Dialog $l
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    Dim dlg As UserDialog /f_c?|  
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    ok = Dialog (dlg) "4{_amgm&<  
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    If ok=0 Then    'cancel button was pressed %^L:K5V  
        Print "Execution cancelled." 8Ee bWs*1  
        End /12D >OK  
    End If a{lDHk`Wf  
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    'Assign accommodation and pupil diameter & use defaults if field left empty /S]W<8d  
    If dlg.TextBox1 = "" Then ^J8sR4p#  
        A = 0           'Default accommodation u@`)u#  
    Else }OeEv@^  
        A = CDbl(dlg.TextBox1) Oc;/'d2  
    End If XFeeNcqF  
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    If dlg.TextBox2 = "" Then W#<&(s4  
        pupilDiam = 4   'Default pupil diameter w"CcWng1  
    Else E)Z$7;N0x  
        pupilDiam = CDbl(dlg.TextBox2) 5XNIX)H  
    End If &FWPb#  
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    Print " " #]s>  
    Print "Accommodation = " & A & " Diopters" Z\=].[,w4  
    Print "Pupil Diameter = " & pupilDiam & " mm" ILUA'T=B0  
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    ' Calculate new parameters with accommodation 8gap _qTo  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness GHHErXT\a  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens `_]Z#X&&h  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens WUid5e2  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens qO  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens x@+m_y  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 1#
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction d{.cIv  
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    'Adjust parameters to account for accommodation <zN  
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    '************************************************************************* V1KWi^  
    'Aqueous thickness (Position of Lens) 47_4`rzy;  
    '************************************************************************* dbkccO}WB  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) }DTpl?l  
    GetCustomElement eID, entity 0&U,WA  
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    parID = FindFullName( "Geometry.Arizona Eye" ) &nk6_{6 c  
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    ' Delete any shift(s) in z b 2n.v.$G  
    count = 0 =R#K`H66j  
    While GetOperationCount(eID)>count c'_-jdi`>_  
        GetOperation eID, count, op I)ub='+&;  
        If op.Type="ShiftZ" Then w>T1
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            DeleteOperation eID,count Lj"~6l`)  
            count=count-1 WYTeu "  
        End If  C~vU  
        count=count+1 >9W ;u`  
    Wend Ebp^-I9.d  
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    'Set new shift in /%Bc*k=ox  
    op.Type = "ShiftZ" "U34D1I)#  
    op.val1 = taq 9+.0ZP?  
    op.parent = parID (LPMEQhI:  
    AddOperation eID, op irCS}Dbw  
    Print "Set aqueous humor thickness = " & taq-0.55 v'B++-%  
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    '************************************************************************* ~=HN30  
    'Radius and conic constant of anterior lens s+>""yi
 
    '*************************************************************************
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    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 9|T%q2O  
    GetConic eID, entity, curv, conic k oo`JHC  
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    SetConic eID, entity, 1/Rant, CCant qUSImgg  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant In|:6YDL&  
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    '************************************************************************* g^(wZ$NH  
    'Radius and conic constant of posterior lens !*.mcIQT  
    '************************************************************************* c&2ZjM  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) (,PO(  
    GetConic eID, entity, curv, conic \`o+Le+%  
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    SetConic eID, entity, 1/Rpost, CCpost 1?"vKm  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost AJSe +1  
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    '*************************************************************************  W-@A  
    'Lens thickness (Position of posterior lens surface) ;A~S){  
    '************************************************************************* _{&znXf>?6  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) UiA\J  
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    ' Delete any z-shift(s) ZAzn-n  
    count = 0 HDYr?t~V  
    While GetOperationCount(eID)>count 8 s!0Z1Roc  
        GetOperation eID, count, op |$#u~<r_ w  
        If op.Type="ShiftZ" Then zu<b#W
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            DeleteOperation eID,count dlN(_6>b  
            count=count-1 X>2_Gol!  
        End If D61CO-E(D  
        count=count+1 Rj9z'?a9  
    Wend on $?c  
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    'Set new z-shift X>EwJ"q#  
    op.Type = "ShiftZ" E#r6e+e1Q%  
    op.val1 = tlens *}Zd QJL  
    op.parent = parID mq$'\c 9.  
    AddOperation eID, op ws Lg6  
    Print "Set lens thickness = " & tlens eIK8J,-  
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    '************************************************************************* V(1Ldl'a  
    'Lens index of refraction vGO-a2Z  
    '************************************************************************* (;P)oB"`C  
    eID = FindMaterial( "Lens" ) E~_2Jf\U  
    GetModelMaterial eID, mat |{+D65R  
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    mat.Nd = nlens K>6#MI  
    SetModelMaterial eID, mat P%f],f  
    Print "Set lens index of refraction = " & nlens oL>m}T  
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    '************************************************************************* P0S;aE  
    'Pupil diameter v'Gqdd-#)  
    '************************************************************************* Rv ?Go2  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) MFcN.M  
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    'Adjust pupil diameter (trimming volume inner hole) G`PSb<h\oc  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" <splLZW3k  
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    ' Adjust pupil location to just in front of the lens 9+U%k(9  
    parID = FindFullName( "Geometry.Arizona Eye" ) vC[)/w  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) xi8RE
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    count = 0 !=--pb  
    While GetOperationCount(eID)>count o0&jel1a  
        GetOperation eID, count, op L B1ui  
        If op.Type="ShiftZ" Then Lgpj<H[  
            DeleteOperation eID,count e*jt(p[Ge  
            count=count-1 |[(4h  
        End If PmyS6a@  
        count=count+1 u&?J+  
    Wend zz 7m\  
    op.Type = "ShiftZ" kX."|]  
    op.val1 = taq-0.01 ZN-J!e"`  
    op.parent = parID .]0B=w* Z  
    AddOperation eID, op zI8Q "b  
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    Print "Set pupil diameter = " & pupilDiam ==`K$rM  
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    'Update AZ Eye subassembly Description iJIPH>UMX  
    eID = FindFullName( "Geometry.Arizona Eye" ) xcwyn\93)  
    GetEntity eID, entity EMzJJe{Cv  
    entity.Description = "Accommodation = " & A & "D" nzE4P3 C+  
    SetEntity eID, entity 0vNEl3f'O  
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    Update .9+"rK}u  
    Print "DONE!" wQWokpP;T7  
    
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End Sub 01}az~&;35  
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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： +'Pl?QyH  
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Accommodation = 4 Diopters g
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Pupil Diameter = 4 mm [?iA`#^d  
Set aqueous humor thickness = 2.81 &0SX*KyI  
Set anterior lens radius = 10.4 and conic constant = -2.375869 >'wl)j$  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 "8%B (a 5A  
Set lens thickness = 3.927 &H$ 3`"p5u  
Set lens index of refraction = 1.42672 F2]v]]F!  
Set pupil diameter = 4 $UavM|  
DONE! oh:q:St  
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