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xunjigd 2016-02-24 12:53

FRED运用：Arizona眼睛模型

简介 5,4m_fBoW  
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。 NwxDxIIH/)  
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模型 gm%cAme  
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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。 *U}ztH-+/  
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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. WEJ-K<A(  
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光源 d"n"A?nXh  
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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。 1*|/N}g)  
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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。 0qIg:+l+  
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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。 RehraY3q  
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[attachment=67933]
图2. 字母F光源的设定方法光 i]s%tEZ1  
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[attachment=67934]
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 9UVT]acq  
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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。 $:\`E 56\  
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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。 ,tcUJ}l  
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[attachment=67936]
图5. 视网膜重点采样规格设定
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脚本 ( Zd(?">i  
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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： "*.N'J\  
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[attachment=67937]
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。 0?( uqjD:  
余下的脚本计算与屈光度有关的所有参数。 oP9 y@U  
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分析 H17I" 5N  
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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。 EFljUT?&  
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[attachment=67939]
图7. 字母F在视网膜上颜色分析
dS3\P5D.*c  
脚本代码 P.5l9N s(O  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. w/ (c}%v}=  
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Dim entity As T_ENTITY =>B"j`oR  
Dim op As T_OPERATION oI[rxr  
Dim mat As T_MODELMATERIAL (tOhuSW  
Dim A As Double <R;wa@a>  
Dim pupilDiam As Double } `r.fD  
Dim eID As Long 5h`LWA B  
Dim parID As Long @+H0D"  
Dim count As Integer k&%i+5X  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double @ci..::5  
Dim tlens As Double, nlens As Double K%+4M#jj5  
Dim curv As Double, conic As Double VQ| {Q}  
Dim ok As Long 8cG`We8l&  
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Sub Main i9XpP(mf  
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    '用户输入对话框 P1T {5u!T  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7xv9v1['  
        TextBox 220,21,40,21,.TextBox1 'default: 0 zMu9A|  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 $b1>,d'oz  
        OKButton 40,91,90,21 |xcC'1WU  
        CancelButton 190,91,90,21 `Ucj_6&Tqs  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 H~nX! sO  
        TextBox 220,49,40,21,.TextBox2 'default: 4 05T?c{ ;  
    End Dialog VGD~) z57  
    Dim dlg As UserDialog t_w\k_ T  
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    ok = Dialog (dlg) un_NBv}  
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    If ok=0 Then    'cancel button was pressed Se'SDJl=  
        Print "Execution cancelled." GI/NouaNfm  
        End x@Z{5w_a  
    End If 1Ub=RyB  
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    'Assign accommodation and pupil diameter & use defaults if field left empty K+!e1 '  
    If dlg.TextBox1 = "" Then X+N5iT  
        A = 0           'Default accommodation ].kj-,5>f  
    Else 8`urkEI^r  
        A = CDbl(dlg.TextBox1) *)-@'{]uB  
    End If /~w*)e)  
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    If dlg.TextBox2 = "" Then XZARy:+bc  
        pupilDiam = 4   'Default pupil diameter aYT!xdCI  
    Else M.t,o\xl  
        pupilDiam = CDbl(dlg.TextBox2) 5)T[ha77u  
    End If LX7P?j  
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    Print " " m\XsU?SuX  
    Print "Accommodation = " & A & " Diopters" {{Ox%Zm  
    Print "Pupil Diameter = " & pupilDiam & " mm" Z/G#3-5)p  
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    ' Calculate new parameters with accommodation #J&3Zds  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >"b W'  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens )~=8Ssu  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens n({%|O<|  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens zY:3*DiM  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens \]f+{d- &  
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    tlens = 3.767 + 0.04*A                  'Lens thickness $Bz};@  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction >dJuk6J&c&  
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    'Adjust parameters to account for accommodation #z.n?d2Gd  
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    '************************************************************************* er7(Wph  
    'Aqueous thickness (Position of Lens) 27ZqdHd  
    '************************************************************************* AJEbiP  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) x;yvv3-$  
    GetCustomElement eID, entity N s0,Z#Z+  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ["Ts7;q9[  
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    ' Delete any shift(s) in z Q&r. wV|  
    count = 0 ;hDk gp  
    While GetOperationCount(eID)>count NJsaTBT  
        GetOperation eID, count, op S!u8JG1  
        If op.Type="ShiftZ" Then /Z:NoTGn  
            DeleteOperation eID,count {f-O~P<Z4  
            count=count-1 <DR|r  
        End If Fnak:R0  
        count=count+1 <A Hzs  
    Wend xtP:Q9!N  
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    'Set new shift in n46!H0mJ  
    op.Type = "ShiftZ" uOzoE_i  
    op.val1 = taq xA7~"q&u  
    op.parent = parID PF/K&&9}  
    AddOperation eID, op v2rO>NY4  
    Print "Set aqueous humor thickness = " & taq-0.55 ^PNDxtd|v  
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    '************************************************************************* o=7,U/{D!  
    'Radius and conic constant of anterior lens d~~, 5E  
    '************************************************************************* vx($o9  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) N`efLOMl]  
    GetConic eID, entity, curv, conic (o B4*  
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    SetConic eID, entity, 1/Rant, CCant 8k-]u3  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant E& 6I`8  
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    '************************************************************************* ?lD)J?j  
    'Radius and conic constant of posterior lens .o`Io[io  
    '************************************************************************* [yN+(^ i  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) \_,p@r]Q  
    GetConic eID, entity, curv, conic /J-'[Mc'D[  
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    SetConic eID, entity, 1/Rpost, CCpost [A =0fg5  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 1}la)lC  
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    '************************************************************************* !i-t6f  
    'Lens thickness (Position of posterior lens surface) B@M9oNWHu  
    '************************************************************************* ~;CNWJtcf(  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) _-({MX[3k<  
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    ' Delete any z-shift(s) 082iE G  
    count = 0 eg/itty  
    While GetOperationCount(eID)>count #fa,}aj  
        GetOperation eID, count, op b]z_2h~`  
        If op.Type="ShiftZ" Then R]%"YQ V  
            DeleteOperation eID,count 03 gbcNo  
            count=count-1 %r1#G.2YW  
        End If YRV h[Bqg`  
        count=count+1 $Ah p4oiE  
    Wend :lo5,B;k  
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    'Set new z-shift FCNYfjB%  
    op.Type = "ShiftZ" Lp:VU-S  
    op.val1 = tlens %]I#]jR  
    op.parent = parID 7d>w]R,Z  
    AddOperation eID, op W;I{4ed6  
    Print "Set lens thickness = " & tlens ^L $`)Ja  
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    '************************************************************************* N 5Om~D  
    'Lens index of refraction EF:ec9 .  
    '************************************************************************* ;iX~3[]  
    eID = FindMaterial( "Lens" ) {7m2vv?Z  
    GetModelMaterial eID, mat C8|Ls(4Ck  
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    mat.Nd = nlens id9QfJ9t  
    SetModelMaterial eID, mat ")MHP~ ?  
    Print "Set lens index of refraction = " & nlens *O'|NQhNx>  
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    '************************************************************************* :'Gn?dv|  
    'Pupil diameter y%%VJ}'X!  
    '************************************************************************* 3>VL>;75[  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) (Z$7;OAI  
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    'Adjust pupil diameter (trimming volume inner hole) #sCR}  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 3_  J'+  
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    ' Adjust pupil location to just in front of the lens uxL+oP0  
    parID = FindFullName( "Geometry.Arizona Eye" ) D+uo gRS61  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) W'@G5e  
    count = 0 " J9  
    While GetOperationCount(eID)>count \wz^Z{U  
        GetOperation eID, count, op xL_QTj  
        If op.Type="ShiftZ" Then P<R^eLZ<&  
            DeleteOperation eID,count =I'iD0eR  
            count=count-1 IIY_Q9in  
        End If Y<W9LF  
        count=count+1 #g$I>\O<  
    Wend W gyRK2#!  
    op.Type = "ShiftZ" @Un/,-ck  
    op.val1 = taq-0.01 d4IQ;u  
    op.parent = parID 2i6=g<   
    AddOperation eID, op vT{(7m!Ra  
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    Print "Set pupil diameter = " & pupilDiam ! U@ETo  
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    'Update AZ Eye subassembly Description >b\|%=(x!*  
    eID = FindFullName( "Geometry.Arizona Eye" ) A7Y CSjB  
    GetEntity eID, entity Ynf "g#(  
    entity.Description = "Accommodation = " & A & "D" fsOlg9  
    SetEntity eID, entity *<cRQfA1  
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    Update 4S 4MQ  
    Print "DONE!" prS%lg>  
      =AaF$R  
End Sub yj_/:eX  
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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： PYi<iSr  
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Accommodation = 4 Diopters Vr1r2G2  
Pupil Diameter = 4 mm a+z>pV|  
Set aqueous humor thickness = 2.81 r:o9:w:  
Set anterior lens radius = 10.4 and conic constant = -2.375869 h/C{  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 oNXYBeu+  
Set lens thickness = 3.927 C\"C12n{  
Set lens index of refraction = 1.42672 Oq<3&*  
Set pupil diameter = 4 n,2p)#?  
DONE! [4qvQ7Y !  
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（文章来源：讯技光电）
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