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xunjigd 2016-02-24 12:53

FRED运用:Arizona眼睛模型

简介 ; KA~Z5x;  
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。 %C0Dw\A*:  
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模型 >usL*b0%  
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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。 ,_P-$lB  
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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.  bLL2  
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光源 B:<VA=  
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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。 H+#FSdy#  
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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。 z{543~Og59  
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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。 zqku e%^?-  
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图2. 字母F光源的设定方法光 vI?, 47Hj+  
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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 3%6? g*  
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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。 :3PH8TL  
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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。 _aphkeqd  
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图5. 视网膜重点采样规格设定
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脚本 <aw[XFg  
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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: #mT"gs  
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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。 S/ *E,))m  
余下的脚本计算与屈光度有关的所有参数。 n<,BmVQ  
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分析 wkq 66?  
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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。 "%_+-C<L4  
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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 #E?4E1bnB  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. h8P)%p  
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Dim entity As T_ENTITY pmM9,6P4@  
Dim op As T_OPERATION >z03{=sAN  
Dim mat As T_MODELMATERIAL E./2jCwI(Y  
Dim A As Double |4JEU3\$  
Dim pupilDiam As Double Q8NX)R  
Dim eID As Long XX@ZQcN  
Dim parID As Long ' %qr.T %  
Dim count As Integer uH]OEz\H'  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double eRYK3W  
Dim tlens As Double, nlens As Double ok[i<zl; '  
Dim curv As Double, conic As Double 9Na$W:P c  
Dim ok As Long +z( Lr=G  
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Sub Main p?!/+  
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    '用户输入对话框 3Ul*QN{6  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 = &]L00u.  
        TextBox 220,21,40,21,.TextBox1 'default: 0 @- xjfC\d  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 %4H%?4  
        OKButton 40,91,90,21 !Ee:o"jG{  
        CancelButton 190,91,90,21 x4 yR8n(  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 \<' ?8ri#  
        TextBox 220,49,40,21,.TextBox2 'default: 4 |N2#ItBbW  
    End Dialog +nL[MSw  
    Dim dlg As UserDialog uph(V  
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    ok = Dialog (dlg) 2 nCA<&  
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    If ok=0 Then    'cancel button was pressed XZ7Lk)IR  
        Print "Execution cancelled." "[J^YKoF  
        End WE?5ehEme  
    End If tA;}h7/Lc~  
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    'Assign accommodation and pupil diameter & use defaults if field left empty Tbq;h ?D  
    If dlg.TextBox1 = "" Then XTy x r  
        A = 0           'Default accommodation KPF1cJ2N  
    Else !a`&O-ye  
        A = CDbl(dlg.TextBox1) ,F|f. 7;  
    End If (HVGlw'`  
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    If dlg.TextBox2 = "" Then iMlWM-wz>O  
        pupilDiam = 4   'Default pupil diameter r&CiSMS*  
    Else K-4PI+qQ\  
        pupilDiam = CDbl(dlg.TextBox2) t_^4`dW`  
    End If 3w=J'(RU  
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    Print " " XSRsGTCC=  
    Print "Accommodation = " & A & " Diopters" aUp g u"  
    Print "Pupil Diameter = " & pupilDiam & " mm" A"]YM'.  
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    ' Calculate new parameters with accommodation @C$]//;  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >7|VR:U?B  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 3BI1fXT4=j  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens G\i9:7 `  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens A^g(k5M*  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 8LKiS  
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    tlens = 3.767 + 0.04*A                  'Lens thickness LVGe]lD  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction @{Q4^'K"  
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    'Adjust parameters to account for accommodation <I?Zk80  
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    '************************************************************************* zCZf%ATq  
    'Aqueous thickness (Position of Lens) dV_G1'  
    '************************************************************************* I9Xuok!0>=  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) vsPu*[%  
    GetCustomElement eID, entity }vuO$j  
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    parID = FindFullName( "Geometry.Arizona Eye" ) V gWRW7Se  
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    ' Delete any shift(s) in z /m1\iM\  
    count = 0 C dn J&N{  
    While GetOperationCount(eID)>count +7Gwg  
        GetOperation eID, count, op Ud?Q%) X  
        If op.Type="ShiftZ" Then .('SW\u-  
            DeleteOperation eID,count Et$2Y-L.  
            count=count-1 B\~}3!j  
        End If -@'FW*b  
        count=count+1 ^#pEPVkY  
    Wend y[;>#j$  
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    'Set new shift in h p1Bi  
    op.Type = "ShiftZ" z/-=%g >HA  
    op.val1 = taq ?<!|  
    op.parent = parID y29m/i:  
    AddOperation eID, op Q &8-\  
    Print "Set aqueous humor thickness = " & taq-0.55 w )f#V s  
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    '************************************************************************* sJZ iI}Xc  
    'Radius and conic constant of anterior lens 6nn *]|7  
    '************************************************************************* K(4_a``05  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) %{W6PrY{  
    GetConic eID, entity, curv, conic "oyo#-5z  
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    SetConic eID, entity, 1/Rant, CCant vM={V$D&  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant UQsN'r\tS  
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    '************************************************************************* E .h*g8bXe  
    'Radius and conic constant of posterior lens F,kZU$  
    '************************************************************************* U{mYTN*:j$  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ! nx{ X  
    GetConic eID, entity, curv, conic w0. u\  
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    SetConic eID, entity, 1/Rpost, CCpost P55fL-vo|}  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost %d @z39-;  
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    '************************************************************************* :jf3HG  
    'Lens thickness (Position of posterior lens surface) Py< }S-:  
    '************************************************************************* 6BlXLQ,8q  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6]N.%Y[(  
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    ' Delete any z-shift(s) TeQV?ZQ#}  
    count = 0 \U0Q<ot/7  
    While GetOperationCount(eID)>count ~*7]r`6\@  
        GetOperation eID, count, op , gHDx  
        If op.Type="ShiftZ" Then Om&Dw |xG8  
            DeleteOperation eID,count \V:^h [ad  
            count=count-1 H,J8M{  
        End If XppOU  
        count=count+1 qs6aB0ln  
    Wend f$( e\+ +  
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    'Set new z-shift AA_%<zK  
    op.Type = "ShiftZ" <@}9Bid!o  
    op.val1 = tlens bt *k.=p  
    op.parent = parID N`i/mP  
    AddOperation eID, op nN;u,}e  
    Print "Set lens thickness = " & tlens =N@t'fOr  
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    '************************************************************************* yZ:qU({KhD  
    'Lens index of refraction CLSK'+l  
    '************************************************************************* Ac6=(B  
    eID = FindMaterial( "Lens" ) & kIFcd@  
    GetModelMaterial eID, mat 1M-pr 8:6s  
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    mat.Nd = nlens $>gFf}#C  
    SetModelMaterial eID, mat zDp2g)  
    Print "Set lens index of refraction = " & nlens 49P 4b<1  
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    '************************************************************************* B!yr!DWv  
    'Pupil diameter 9L9sqZUB  
    '************************************************************************* l6B@qYLZ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) q4q6c")zp  
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    'Adjust pupil diameter (trimming volume inner hole) ]_Xlq_[/r  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 0V]s:S  
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    ' Adjust pupil location to just in front of the lens 0c &+|> !  
    parID = FindFullName( "Geometry.Arizona Eye" ) )Z$!PqRw@u  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) l0] EX>"E  
    count = 0 Q\)F;:|  
    While GetOperationCount(eID)>count {*KEP  
        GetOperation eID, count, op |}1dFp  
        If op.Type="ShiftZ" Then E4!Fupkpf  
            DeleteOperation eID,count Al'3?  
            count=count-1 P2!C|SLK  
        End If ~ 1pr~  
        count=count+1 u>$t'  
    Wend m* ;ERK  
    op.Type = "ShiftZ" bcR_E5x$  
    op.val1 = taq-0.01 DJir{ \F  
    op.parent = parID OB7hlW  
    AddOperation eID, op fnY.ao1-s[  
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    Print "Set pupil diameter = " & pupilDiam eQ"E   
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    'Update AZ Eye subassembly Description  IB<d  
    eID = FindFullName( "Geometry.Arizona Eye" ) M;NX:mX9  
    GetEntity eID, entity r/sNrB1U"y  
    entity.Description = "Accommodation = " & A & "D" sGb{9.WK  
    SetEntity eID, entity __@BUK{q  
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    Update kLY^!  
    Print "DONE!" C>~TI,5a3  
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End Sub FqifriLN  
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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: iUwzs&frd  
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Accommodation = 4 Diopters [2koe.?(  
Pupil Diameter = 4 mm fLVAKn  
Set aqueous humor thickness = 2.81 OH"XrCX7n  
Set anterior lens radius = 10.4 and conic constant = -2.375869 {U1m.30n  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 w:l"\Tm  
Set lens thickness = 3.927 vj*%Q(E6Pt  
Set lens index of refraction = 1.42672 ,P Z ge  
Set pupil diameter = 4 yBRC*0+Vy  
DONE! rbQR,Nf2x  
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(文章来源:讯技光电)
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