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xunjigd 2016-02-24 12:53

FRED运用：Arizona眼睛模型

简介 tV h"C%Vkr  
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。 ZEso2|   
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模型 M0$E_*  
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模型的定义如表1种所示，由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度（A）来决定。 H4$f+  
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Table 1. AZ眼睛模型的定义
[attachment=67931]
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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. / }*}r  
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光源 ';v1AX}5q  
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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。 y+KAL{AGK  
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[attachment=67932]
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。 "BZ@m:I6hy  
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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。 }F"98s W  
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图2. 字母F光源的设定方法光 q@tym5  
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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 .(3ec/i4CF  
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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。 U`5/tNx  
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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。 vn!3Z!dm(  
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图5. 视网膜重点采样规格设定
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脚本 n$v4$_qS  
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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： 7?{y&sf  
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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。 -e_o p'`  
余下的脚本计算与屈光度有关的所有参数。 ZhoV,/\+  
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分析 3z u6#3^  
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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。 LrT EF j  
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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 L AH">E  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. _>rM[\|X  
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Dim entity As T_ENTITY '&dT   
Dim op As T_OPERATION 9x|`XAB  
Dim mat As T_MODELMATERIAL n:2._s T  
Dim A As Double Y;%LwDC  
Dim pupilDiam As Double (CY D]n  
Dim eID As Long 5bAdF'~  
Dim parID As Long MIn_?r  
Dim count As Integer y_w  <3  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double /t`\b [  
Dim tlens As Double, nlens As Double J-<_e??  
Dim curv As Double, conic As Double Z\xnPhV  
Dim ok As Long ,[zSz8R  
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Sub Main CbC [aVA=  
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    '用户输入对话框 2#sFY/@  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 iw3\`,5   
        TextBox 220,21,40,21,.TextBox1 'default: 0 6]~/`6Dub  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 "a(4])  
        OKButton 40,91,90,21 E;{RNf|  
        CancelButton 190,91,90,21 FHw%ynC  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 \X _}\_c,d  
        TextBox 220,49,40,21,.TextBox2 'default: 4 z<%bNnSO  
    End Dialog HbI{Xf[6LP  
    Dim dlg As UserDialog HI 1T  
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    ok = Dialog (dlg) hTzj{}w  
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    If ok=0 Then    'cancel button was pressed 6j XDLI  
        Print "Execution cancelled." n:OXv}pv  
        End WA~[) S0  
    End If ye9GBAj /  
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    'Assign accommodation and pupil diameter & use defaults if field left empty I`X!M!dB)  
    If dlg.TextBox1 = "" Then L"vrX  
        A = 0           'Default accommodation 6qFzo1LO  
    Else \}v@!PQl  
        A = CDbl(dlg.TextBox1) o>C,Db~L/  
    End If $cHU,  
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    If dlg.TextBox2 = "" Then ))f@9m  
        pupilDiam = 4   'Default pupil diameter -0kMh.JYR  
    Else Qe>_\-f  
        pupilDiam = CDbl(dlg.TextBox2) *3`R W<Z  
    End If :_6o|9J\t  
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    Print " " J<"K`|F  
    Print "Accommodation = " & A & " Diopters" * @]wT'  
    Print "Pupil Diameter = " & pupilDiam & " mm" C/Tk`C&  
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    ' Calculate new parameters with accommodation m(U.BXo  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness rIPfO'T?  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens i@nRZ$K  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens '1LN)Yw  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens  94PI  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens f&4+-w.:V|  
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    tlens = 3.767 + 0.04*A                  'Lens thickness >^Wpc  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Zt! $"N.,  
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    'Adjust parameters to account for accommodation F$tzsz,9n  
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    '************************************************************************* yZ,pH1  
    'Aqueous thickness (Position of Lens) S8dfe~|7:  
    '************************************************************************* :?zq!  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) !AE;s}v)0{  
    GetCustomElement eID, entity h<3b+*wYJC  
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    parID = FindFullName( "Geometry.Arizona Eye" ) a5/, O4Q  
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    ' Delete any shift(s) in z #~-Xt! I  
    count = 0 pP":,8Q{  
    While GetOperationCount(eID)>count i /[{xRXiR  
        GetOperation eID, count, op `oikSx$vB.  
        If op.Type="ShiftZ" Then RNw#s R  
            DeleteOperation eID,count W`9{RZ'  
            count=count-1 "rLm)$I  
        End If 6AJ`)8HX  
        count=count+1 1q!k#Cliu  
    Wend #M!$CGi (  
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    'Set new shift in YU-wE';H6  
    op.Type = "ShiftZ" A+M4=  
    op.val1 = taq Ur< (TM  
    op.parent = parID {z_cczJ-  
    AddOperation eID, op ];Noe9o  
    Print "Set aqueous humor thickness = " & taq-0.55 9D\E0YG X/  
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    '************************************************************************* ]I,&Bme  
    'Radius and conic constant of anterior lens mv:@D  
    '************************************************************************* 8Gy]nD  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) P?>:YY53  
    GetConic eID, entity, curv, conic ,0h{RZKw  
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    SetConic eID, entity, 1/Rant, CCant w,j!%N  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant P{K\}+9F   
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    '************************************************************************* Dz~^AuD6  
    'Radius and conic constant of posterior lens cD`?" n  
    '************************************************************************* vo }4N[]Sb  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) E]~ #EFc  
    GetConic eID, entity, curv, conic GPh;r7xg6  
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    SetConic eID, entity, 1/Rpost, CCpost n%36a(] t  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 3n7>qZ.d  
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    '************************************************************************* K{I"2c  
    'Lens thickness (Position of posterior lens surface) sYXLVJ>b  
    '************************************************************************* cLL2 '  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) bz nMD  
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    ' Delete any z-shift(s) Z:h'kgG&  
    count = 0 Xmmj.ZUr  
    While GetOperationCount(eID)>count |qQ6>IZ  
        GetOperation eID, count, op aO inD  
        If op.Type="ShiftZ" Then )!AH0p  
            DeleteOperation eID,count |4/rVj"  
            count=count-1 ~u0<c:C^  
        End If Y]6d Yq{k  
        count=count+1 &k*oG: J3  
    Wend 8v/,< eARJ  
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    'Set new z-shift Q$p3cepsK  
    op.Type = "ShiftZ" GKWsJO5 n  
    op.val1 = tlens `Zmdlp@  
    op.parent = parID = YO<.(Lu  
    AddOperation eID, op -XnIDXM  
    Print "Set lens thickness = " & tlens k f Y;  
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    '************************************************************************* 'tMD=MH  
    'Lens index of refraction 'e<8j  
    '************************************************************************* N6BOUU]  
    eID = FindMaterial( "Lens" ) s."N7F  
    GetModelMaterial eID, mat _ j'm2BA O  
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    mat.Nd = nlens cna%;f.  
    SetModelMaterial eID, mat \goiW;b  
    Print "Set lens index of refraction = " & nlens nZYO}bv\  
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    '************************************************************************* .P5' \  
    'Pupil diameter #t Pc<p6m  
    '************************************************************************* LrdED[Z  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 1)97AkN(O  
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    'Adjust pupil diameter (trimming volume inner hole) _XT;   
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 7nxH>.,Q>  
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    ' Adjust pupil location to just in front of the lens (u@X5O(a  
    parID = FindFullName( "Geometry.Arizona Eye" ) Y0Tw:1a  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) _ A{F2M  
    count = 0 A ^hafBa  
    While GetOperationCount(eID)>count )iC@n8f7o  
        GetOperation eID, count, op I%Z=O=  
        If op.Type="ShiftZ" Then <f)T*E^5%  
            DeleteOperation eID,count #_3ZF"[zq  
            count=count-1 eq"Xwq*  
        End If l*CCnqE  
        count=count+1 rN.8-  
    Wend ' qT\I8%  
    op.Type = "ShiftZ" gCRPaF6  
    op.val1 = taq-0.01 iM1E**WCtv  
    op.parent = parID 3H>\hZ  
    AddOperation eID, op L"c.15\  
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    Print "Set pupil diameter = " & pupilDiam F4V) 0)G  
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    'Update AZ Eye subassembly Description 5}5oj37x  
    eID = FindFullName( "Geometry.Arizona Eye" ) }=gD,]2x8  
    GetEntity eID, entity QAl4w)F  
    entity.Description = "Accommodation = " & A & "D" muK.x7zyl  
    SetEntity eID, entity kQ2WdpZ/  
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    Update 5V/]7>b1  
    Print "DONE!" qv:DpK  
     uB6Mj dp6  
End Sub ApggTzh@  
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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： aehB,l0  
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Accommodation = 4 Diopters y5^OD63s  
Pupil Diameter = 4 mm {C8IYBm  
Set aqueous humor thickness = 2.81 ,@M<O!%Cs  
Set anterior lens radius = 10.4 and conic constant = -2.375869 5vS[{;<&  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 hc9 ON&L\>  
Set lens thickness = 3.927 4}*.0'Hz  
Set lens index of refraction = 1.42672 UbIUc}ge  
Set pupil diameter = 4 "So "oT1  
DONE! xj AU Csq  
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（文章来源：讯技光电）
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