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xunjigd 2016-02-24 12:53

FRED运用：Arizona眼睛模型

简介 S<^*jheO5  
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。 KobNi#O+  
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模型 ahgm*Cpc  
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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。 zo66=vE!  
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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. :32  
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光源 e* gCc7zz  
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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。 _%Q\G,a;  
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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。 )mO|1IDTN  
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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。 hNXP-s  
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图2. 字母F光源的设定方法光 T 1m097  
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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 rlu{C4l  
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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。 Tysh~C|1  
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[attachment=67935]
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。 *ie#9jA  
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图5. 视网膜重点采样规格设定
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脚本 ,c_[`q\  
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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： l'-dB  
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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。 WQ4:='(  
余下的脚本计算与屈光度有关的所有参数。 04NI.Jv  
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分析 y|V/xm+Fp  
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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。 g':mM*j&  
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[attachment=67939]
图7. 字母F在视网膜上颜色分析
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脚本代码 q.i@Lvu#  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. cl{x5>.'#  
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Dim entity As T_ENTITY -?<wvUbR{  
Dim op As T_OPERATION 2;.7c+r0  
Dim mat As T_MODELMATERIAL 2Xk(3J!!'a  
Dim A As Double rFZB6A<(]  
Dim pupilDiam As Double oH!sJ&"#_  
Dim eID As Long ]hTYh^'e  
Dim parID As Long $6atr-Pb  
Dim count As Integer 9ET2uDZpL  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double \^SL Zhe  
Dim tlens As Double, nlens As Double Y>Q9?>}Q  
Dim curv As Double, conic As Double Rj9ME,u  
Dim ok As Long pu nc'~  
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Sub Main GEfX,9LF&  
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    '用户输入对话框 MGX %U6  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 N5csq(  
        TextBox 220,21,40,21,.TextBox1 'default: 0 zAt!jP0E  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 cqr!*  
        OKButton 40,91,90,21 vG#|CO9  
        CancelButton 190,91,90,21 ]"q[hF*PM  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 gt6*x=RCrQ  
        TextBox 220,49,40,21,.TextBox2 'default: 4 :^lyVQ%@  
    End Dialog l*("[?>I  
    Dim dlg As UserDialog U#1T HO`  
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    ok = Dialog (dlg) qdm5dQ (c  
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    If ok=0 Then    'cancel button was pressed 3G8BYP  
        Print "Execution cancelled." C*ZgjFvB  
        End q% )Y  
    End If |gx{un`  
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    'Assign accommodation and pupil diameter & use defaults if field left empty vlIet$ k  
    If dlg.TextBox1 = "" Then 6#6Ve$Vl]  
        A = 0           'Default accommodation )y'`C@ijI  
    Else *aS|4M-  
        A = CDbl(dlg.TextBox1) p=\DZU~1  
    End If I>bLgt]u3  
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    If dlg.TextBox2 = "" Then $1.iMHb  
        pupilDiam = 4   'Default pupil diameter TbU\qcm]]  
    Else REB8_H"  
        pupilDiam = CDbl(dlg.TextBox2) \`jFy[(Pa'  
    End If lZV]Z3=p'0  
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    Print " " Y1+4ppZ  
    Print "Accommodation = " & A & " Diopters" fo&q/;l\  
    Print "Pupil Diameter = " & pupilDiam & " mm" rw8O<No4.o  
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    ' Calculate new parameters with accommodation cQzd0X  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness jpZX5_o  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens HnUM:-6  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens kf_s.Dedw  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens X<K[` =I  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens +che Lc  
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    tlens = 3.767 + 0.04*A                  'Lens thickness WW0N"m'  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 1sYwFr5  
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    'Adjust parameters to account for accommodation H.XD8qi3W  
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    '************************************************************************* FT/H~|Z>  
    'Aqueous thickness (Position of Lens) g10$pf+L  
    '************************************************************************* .hn{m9|U  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) b.47KJzt  
    GetCustomElement eID, entity 8<0H(lj7_  
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    parID = FindFullName( "Geometry.Arizona Eye" ) `(H]aTLt ,  
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    ' Delete any shift(s) in z eT[ ,k[#q  
    count = 0 s!nFc{  
    While GetOperationCount(eID)>count # Fw<R'c  
        GetOperation eID, count, op x% k4Lm  
        If op.Type="ShiftZ" Then o B_c6]K  
            DeleteOperation eID,count QB#f'X  
            count=count-1 mV@.JFXKP  
        End If 60[f- 0X  
        count=count+1 hZY+dHa]  
    Wend '|':W6m,  
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    'Set new shift in r-^Ju6w{  
    op.Type = "ShiftZ" =+T{!+|6P  
    op.val1 = taq YUfuS3sX}  
    op.parent = parID S"CsY2;  
    AddOperation eID, op 7SoxsT)  
    Print "Set aqueous humor thickness = " & taq-0.55 }EE  
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    '************************************************************************* ,8;;#XR3  
    'Radius and conic constant of anterior lens !lm^(SSv  
    '************************************************************************* g v&xC 6>  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) J^hj R%H  
    GetConic eID, entity, curv, conic 1& YcCN\k  
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    SetConic eID, entity, 1/Rant, CCant L; Nz\sJ  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant , =IbZ  
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    '************************************************************************* Pw1V1v&> q  
    'Radius and conic constant of posterior lens 92]>"  
    '************************************************************************* bnWIB+%_  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" )  .r[DqC  
    GetConic eID, entity, curv, conic  P%xk   
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    SetConic eID, entity, 1/Rpost, CCpost MkC25  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 2fO ~%!.G  
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    '************************************************************************* E$ q/4  
    'Lens thickness (Position of posterior lens surface) '-D-H}%;}M  
    '************************************************************************* |n=m8X  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) kR%CSLOVy  
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    ' Delete any z-shift(s) 09_3`K. *  
    count = 0 |D$U{5}Mv  
    While GetOperationCount(eID)>count 8n?P'iM  
        GetOperation eID, count, op "@ Zy+zLU  
        If op.Type="ShiftZ" Then d5T0#ue/e  
            DeleteOperation eID,count _;yp^^S  
            count=count-1 l|%7)2TyG)  
        End If .P# c/SQp  
        count=count+1 JZD27[b  
    Wend $T^O38$  
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    'Set new z-shift "#rlL^9v  
    op.Type = "ShiftZ" 1mJBxg}(  
    op.val1 = tlens }{ pNasAU  
    op.parent = parID Um9!<G=;  
    AddOperation eID, op [m|\N  
    Print "Set lens thickness = " & tlens hDl& KE  
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    '************************************************************************* ]QtdT8~  
    'Lens index of refraction ?fnJ`^|-r  
    '************************************************************************* > 9JzYI^  
    eID = FindMaterial( "Lens" ) m589C+7  
    GetModelMaterial eID, mat ^^}  
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    mat.Nd = nlens c<A@Op"A  
    SetModelMaterial eID, mat "h_n/}r=  
    Print "Set lens index of refraction = " & nlens cI?dvfU?  
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    '************************************************************************* +C/K@:p  
    'Pupil diameter UQPd@IVu6  
    '************************************************************************* QP7EPaW  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) s)375jCga  
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    'Adjust pupil diameter (trimming volume inner hole) w<J$12 "p+  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" M7eO5  
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    ' Adjust pupil location to just in front of the lens _Y|k \|'  
    parID = FindFullName( "Geometry.Arizona Eye" ) X~P0Q  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) A}~hc&J  
    count = 0 ZA1?'  
    While GetOperationCount(eID)>count G&/}P$  
        GetOperation eID, count, op m3F.-KPO  
        If op.Type="ShiftZ" Then =XQ3sk6U  
            DeleteOperation eID,count <Sm =,Sw  
            count=count-1 3y r{B Xn  
        End If L;,Nh  
        count=count+1 V F6OC4 K  
    Wend VXn]*Mo  
    op.Type = "ShiftZ" H^K(1  
    op.val1 = taq-0.01 89`AF1  
    op.parent = parID 1^}() H62}  
    AddOperation eID, op D4Uz@2_  
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    Print "Set pupil diameter = " & pupilDiam wjq f u /  
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    'Update AZ Eye subassembly Description e~'y%|D  
    eID = FindFullName( "Geometry.Arizona Eye" ) ]=WJ%p1l  
    GetEntity eID, entity A. U<  
    entity.Description = "Accommodation = " & A & "D" "LaNXZ9  
    SetEntity eID, entity y"cK@sOo  
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    Update g}ciG!0  
    Print "DONE!" tI*u"%#t  
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End Sub [ ]3xb`<&  
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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： u-OwL1S+  
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Accommodation = 4 Diopters rU<  H7U  
Pupil Diameter = 4 mm %dw-}1X  
Set aqueous humor thickness = 2.81 |rW}s+Kcr  
Set anterior lens radius = 10.4 and conic constant = -2.375869 S,G=MI"  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 U+@yx>!  
Set lens thickness = 3.927 Mr2dhSQ !  
Set lens index of refraction = 1.42672 r5lp<md  
Set pupil diameter = 4 F m h;d*IT  
DONE! |WXu;uf$.u  
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（文章来源：讯技光电）
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