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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 !pkIaCxs  
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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。 R!lug;u#  
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模型 Jj 5VBI!Ok  
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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。 [u37 Hy_Gi  
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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. pek=!nZ  
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光源 cofdDHXfQI  
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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。 9V[}#(f$  
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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。 u[Si=)`VPk  
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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。 `j9\]50Z>  
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图2. 字母F光源的设定方法光 @"1Z;.S8V  
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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 F:q8.^HTJ  
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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。 O9/)_:Wdh  
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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。 X0-PJ-\aD@  
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图5. 视网膜重点采样规格设定
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脚本 jC>#`gD  
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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: O-K*->5S  
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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。 9_iwikD  
余下的脚本计算与屈光度有关的所有参数。 VjNr<~|d  
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分析 VPuR4 p.  
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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。 +xO3<u  
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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 qlYi:uygY  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 6Aq]I$  
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Dim entity As T_ENTITY adIrrK  
Dim op As T_OPERATION T 4p}5ew'  
Dim mat As T_MODELMATERIAL L6Brs"9B  
Dim A As Double G'#u!<(^h  
Dim pupilDiam As Double D"$Y, d  
Dim eID As Long 2EZ7Vdz2  
Dim parID As Long '@ Y@Fs  
Dim count As Integer ,f>9oOqqA  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double `iM%R3&  
Dim tlens As Double, nlens As Double jX8)Ov5Mv  
Dim curv As Double, conic As Double %<a3[TQd`\  
Dim ok As Long yq[/9PciA  
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Sub Main z,x )Xx  
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    '用户输入对话框 gj @9(dk%  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 h8 N|m0W  
        TextBox 220,21,40,21,.TextBox1 'default: 0 [~ 2m*Q  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 UE"v+GH  
        OKButton 40,91,90,21 G~(\N?2  
        CancelButton 190,91,90,21 %A'mXatk  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 [BJzZ>cY  
        TextBox 220,49,40,21,.TextBox2 'default: 4 wn!=G~nB  
    End Dialog ~5%3]  
    Dim dlg As UserDialog lGWz  
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    ok = Dialog (dlg) W}TP(~x'N  
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    If ok=0 Then    'cancel button was pressed kBcTXl  
        Print "Execution cancelled." -sKtT 9o  
        End oo &|(+"O_  
    End If 5;" $X 1{  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 3 mAizq3  
    If dlg.TextBox1 = "" Then |e2s\?nB0S  
        A = 0           'Default accommodation {m~)~/z?  
    Else R@jMFh;  
        A = CDbl(dlg.TextBox1) wzju)qS  
    End If fv+ET:T%  
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    If dlg.TextBox2 = "" Then cpP}NJb0;%  
        pupilDiam = 4   'Default pupil diameter ^O@eyP  
    Else >zX^*T#  
        pupilDiam = CDbl(dlg.TextBox2) z=U+FHdh/-  
    End If ?rQ .nN  
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    Print " " -_5Dk'R#`  
    Print "Accommodation = " & A & " Diopters" a dr\l5pWQ  
    Print "Pupil Diameter = " & pupilDiam & " mm" '#3FEo  
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    ' Calculate new parameters with accommodation OHBCanZZ,  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness HYGd :SeH  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens T\.(e*hC  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 9G SpDc  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens TY %zw6 #p  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens b7\>=  
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    tlens = 3.767 + 0.04*A                  'Lens thickness ;k`51=Wi  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction /fb}]e]N  
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    'Adjust parameters to account for accommodation E!1\9wzM{  
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    '************************************************************************* i'H]N8,A  
    'Aqueous thickness (Position of Lens) 96~y\X@x  
    '************************************************************************* dL% *;   
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) [T =>QS@g  
    GetCustomElement eID, entity +%\Ci!%b  
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    parID = FindFullName( "Geometry.Arizona Eye" ) >YWK"~|i~  
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    ' Delete any shift(s) in z /mz.HCs  
    count = 0 `dV2\^*A  
    While GetOperationCount(eID)>count H%Vf$1/TF  
        GetOperation eID, count, op &nr{-][  
        If op.Type="ShiftZ" Then TxF^zx\  
            DeleteOperation eID,count ,P}7e)3  
            count=count-1 jXf@JxQ  
        End If B2]52Fg-"  
        count=count+1 <lIm==U<-  
    Wend i *:QbMb  
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    'Set new shift in @br)m](@  
    op.Type = "ShiftZ" oH0g>E;  
    op.val1 = taq , v} )  
    op.parent = parID p1d%&e  
    AddOperation eID, op Cscu   
    Print "Set aqueous humor thickness = " & taq-0.55 hmkb!)  
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    '************************************************************************* ]j:k!=Ss?  
    'Radius and conic constant of anterior lens 0~BaQ, A @  
    '************************************************************************* SzB<PP2  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) E`JW4)AH  
    GetConic eID, entity, curv, conic HoAg8siQ  
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    SetConic eID, entity, 1/Rant, CCant cKkH*0B5  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 9yTdbpY  
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    '************************************************************************* 02[m{a-  
    'Radius and conic constant of posterior lens L:Rg3eo  
    '************************************************************************* H*k\C  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) R7(XDX=[ s  
    GetConic eID, entity, curv, conic [LjiLKW  
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    SetConic eID, entity, 1/Rpost, CCpost ;yN Y/  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost [6RODp3')  
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    '************************************************************************* l2 n`fZL  
    'Lens thickness (Position of posterior lens surface) PQl A(v+S  
    '************************************************************************* ',`Qx{tQ)  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 8Pd9&/Y  
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    ' Delete any z-shift(s) n.9k5r@  
    count = 0 >>J$`0kM*  
    While GetOperationCount(eID)>count 3AdYZ7J  
        GetOperation eID, count, op j"~"-E(79  
        If op.Type="ShiftZ" Then 08jk~$%  
            DeleteOperation eID,count Lb Jf5xdi  
            count=count-1 EgPL+qL  
        End If jG&HPVr  
        count=count+1 N,XjZ26  
    Wend VOr: G85*s  
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    'Set new z-shift _Cz98VqRk  
    op.Type = "ShiftZ" bnkZWw'9  
    op.val1 = tlens `~d7l@6F  
    op.parent = parID rZ(#t{]=!  
    AddOperation eID, op BhAT@%  
    Print "Set lens thickness = " & tlens [g}#R#Y)  
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    '************************************************************************* %-fXa2  
    'Lens index of refraction hC"'cUrcN  
    '************************************************************************* y-H9fWi8Y&  
    eID = FindMaterial( "Lens" ) ?QF xds  
    GetModelMaterial eID, mat Zl9  
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    mat.Nd = nlens qm/>\4eLt  
    SetModelMaterial eID, mat e}{#VB<  
    Print "Set lens index of refraction = " & nlens o<lmU8xB=  
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    '************************************************************************* :Wx7a1.Jz  
    'Pupil diameter c oZK  
    '************************************************************************* q90RTX'CY  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) '")'h  
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    'Adjust pupil diameter (trimming volume inner hole) 8dx 7@y?z  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" rd%uc~/  
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    ' Adjust pupil location to just in front of the lens 3 []ltN_  
    parID = FindFullName( "Geometry.Arizona Eye" ) ,<P"\W  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 2Jiy`(P  
    count = 0 <tZtt9j_  
    While GetOperationCount(eID)>count I&i6-xp  
        GetOperation eID, count, op $FT6c@&y  
        If op.Type="ShiftZ" Then }sqFvab<  
            DeleteOperation eID,count o@PvA1  
            count=count-1 aUa+]H[  
        End If Qh8pOUD0l}  
        count=count+1 8*?H~q~  
    Wend U:7w8$_  
    op.Type = "ShiftZ" UzSDXhzObf  
    op.val1 = taq-0.01 KY< $+/B!  
    op.parent = parID &m36h`tM  
    AddOperation eID, op ktfxb <%  
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    Print "Set pupil diameter = " & pupilDiam (  -q0!]E  
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    'Update AZ Eye subassembly Description %/\sn<6C}  
    eID = FindFullName( "Geometry.Arizona Eye" ) -0;{  
    GetEntity eID, entity WRbdv{ 1E  
    entity.Description = "Accommodation = " & A & "D" -@w}}BR  
    SetEntity eID, entity 7~1Fy{tc  
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    Update ncUhCp?'  
    Print "DONE!" `%Kj+^|DS  
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End Sub IY!.j5q8  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: 0wqw5KC  
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Accommodation = 4 Diopters 9+ve0P7$  
Pupil Diameter = 4 mm \N|}V.r  
Set aqueous humor thickness = 2.81 J<"Z6 '0v  
Set anterior lens radius = 10.4 and conic constant = -2.375869 u#u/uS"  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 @HI@PZ>  
Set lens thickness = 3.927 +DefV,Ny  
Set lens index of refraction = 1.42672 JY:Fu  
Set pupil diameter = 4 8(NS;?  
DONE! beYGP  
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