[技术]Arizona眼睛模型 [复制链接]

简介 v-^tj}jA  
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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。 $bfmsCcHL  
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模型 [!8bjc]c
 
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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。 AZA5>Y
 
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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. Y6d~hLC  
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光源 s0/m qZ]s  
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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。 csxn"Dz\  
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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。 qt/6o|V  
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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。 *yo'Nqu  
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视网膜的散射 jsr
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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。 8m `Y  
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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。 hNgT/y8  
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脚本 R[fQ$` M  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框，如下图所示： O&~ @ior  
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如果“OK”按钮按下，将会核对对话框下面的代码行，如果点击取消则脚本终止。然后输入的参数赋予变量，如果此处是保留为空白，则使用默认值。因此，如果没有值输入并点击“OK”按钮，则脚本是以屈光度为0，光瞳直径为4mm来运行的。 qD=b+\F  
余下的脚本计算与屈光度有关的所有参数。 GkU$Z @  
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分析 7M5HvG#w%  
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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。 qf<o"B|_9  
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脚本代码 ?@`5^7*  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. :6EX-Xyj  
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Dim entity As T_ENTITY [)I W9E v  
Dim op As T_OPERATION I|c?*~7*  
Dim mat As T_MODELMATERIAL 
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Dim A As Double iXXaB+w  
Dim pupilDiam As Double yOb']
 
Dim eID As Long r~fnK%|  
Dim parID As Long _z.CV<  
Dim count As Integer c*"P+  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double C$LRX7Z`o  
Dim tlens As Double, nlens As Double F*Yx1vj  
Dim curv As Double, conic As Double hg'eSU$J  
Dim ok As Long 0D `9  
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Sub Main t0P_$+w.>  
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    '用户输入对话框 5N;xo??  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 q9InO]s&~=  
        TextBox 220,21,40,21,.TextBox1 'default: 0 Ip8:~Fl]  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ;>X;cZMd  
        OKButton 40,91,90,21
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        CancelButton 190,91,90,21 JEZ0O&_R  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 3(.Y>er%U  
        TextBox 220,49,40,21,.TextBox2 'default: 4 $I ,Np)i  
    End Dialog "EWq{l_I5$  
    Dim dlg As UserDialog 9j5Z!Vsy  
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    ok = Dialog (dlg) %6M%PR~
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    If ok=0 Then    'cancel button was pressed XZ8]se"C  
        Print "Execution cancelled." I_`NjJ;61  
        End jgkY^l  
    End If ]Al)>  
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    'Assign accommodation and pupil diameter & use defaults if field left empty FS('*w&bP  
    If dlg.TextBox1 = "" Then j4=\
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        A = 0           'Default accommodation s,Fts3+  
    Else lC d\nE8G  
        A = CDbl(dlg.TextBox1) cN\_1  
    End If i.-2 w6  
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    If dlg.TextBox2 = "" Then 2G3Hi;q18  
        pupilDiam = 4   'Default pupil diameter 'S#^70kt  
    Else PVmePgF   
        pupilDiam = CDbl(dlg.TextBox2) 3 "Qg"\  
    End If c<q~T >0k  
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    Print " " AOTtAV_e  
    Print "Accommodation = " & A & " Diopters" : 'jVA  
    Print "Pupil Diameter = " & pupilDiam & " mm" 'Ir  
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    ' Calculate new parameters with accommodation s]D1s%Mx  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness q+w] Xs;  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens zMO xJ   
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens #Ny+6XM  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens iqsR]mab  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens dXU6TCjU7  
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    tlens = 3.767 + 0.04*A                  'Lens thickness  (8/&  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction /6y;fx  
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    'Adjust parameters to account for accommodation 9h6siK(F  
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    '************************************************************************* }5B\:*yW  
    'Aqueous thickness (Position of Lens) oS_YQOoD  
    '************************************************************************* tS,AS,vy]  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) N4WX}  
    GetCustomElement eID, entity |"eC0u  
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    parID = FindFullName( "Geometry.Arizona Eye" ) `t g=__D  
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    ' Delete any shift(s) in z ]BmnE#n&  
    count = 0 DMKtTt[}  
    While GetOperationCount(eID)>count [o 6  
        GetOperation eID, count, op W/%9=g$m  
        If op.Type="ShiftZ" Then V7 hO}  
            DeleteOperation eID,count q$}gQ9'z'  
            count=count-1 ')(U<5y)  
        End If Yv"B-oy  
        count=count+1 FbW$H]C$  
    Wend WkPT6d  
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    'Set new shift in w)/~Gn676  
    op.Type = "ShiftZ" 6Z@T /"mU(  
    op.val1 = taq Ejyo oO45  
    op.parent = parID ]Z*B17//  
    AddOperation eID, op p>W@h*[6w  
    Print "Set aqueous humor thickness = " & taq-0.55 s Dsq:z  
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    '************************************************************************* $JiypX^DOP  
    'Radius and conic constant of anterior lens [|(=15;  
    '************************************************************************* #E_
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    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) D@c@Dt  
    GetConic eID, entity, curv, conic ylQ9Su>o  
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    SetConic eID, entity, 1/Rant, CCant ?0lz!Nq'S  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Qr?1\H:Lq  
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    '************************************************************************* 4"\%/kG  
    'Radius and conic constant of posterior lens ciFqj3JS  
    '************************************************************************* }$(\,SzW  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) +/hd;s$x  
    GetConic eID, entity, curv, conic Uyd'uC  
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    SetConic eID, entity, 1/Rpost, CCpost + 7wMM#z  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost "ZFH_5<  
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    '************************************************************************* 6r`Xi&  
    'Lens thickness (Position of posterior lens surface) Xx\,<8Xn  
    '*************************************************************************
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) xT!<x({  
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    ' Delete any z-shift(s) aS~~*UHW  
    count = 0 dAy\IfZX=  
    While GetOperationCount(eID)>count Z{?T1 =n  
        GetOperation eID, count, op  "+Sq}WR  
        If op.Type="ShiftZ" Then J5Ti@(G5V  
            DeleteOperation eID,count nwIj?(8x  
            count=count-1 (;-_j/  
        End If 6Xbf3So  
        count=count+1 #qeC)T  
    Wend WuTkYiF  
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    'Set new z-shift 6{yn;D4  
    op.Type = "ShiftZ" m7i(0jd +  
    op.val1 = tlens : t
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    op.parent = parID ab]Q1kD  
    AddOperation eID, op '%o^#gJp  
    Print "Set lens thickness = " & tlens ,Z}ST|$u  
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    '************************************************************************* 'pB?  
    'Lens index of refraction X8A.ag0Uu  
    '************************************************************************* ef/43+F^x  
    eID = FindMaterial( "Lens" ) =d]}7PO~  
    GetModelMaterial eID, mat ixE w!t  
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    mat.Nd = nlens 9<3fH J?vq  
    SetModelMaterial eID, mat ?CcX>R-/  
    Print "Set lens index of refraction = " & nlens 4t3>`x 7  
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    '*************************************************************************
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    'Pupil diameter Q>cEG"  
    '************************************************************************* ?e,:x ]\L  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) p(K^Zc  
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    'Adjust pupil diameter (trimming volume inner hole) CF@*ki3X  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" %b2Hm9r+  
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    ' Adjust pupil location to just in front of the lens nHRk2l|  
    parID = FindFullName( "Geometry.Arizona Eye" ) N Z,}v3  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) OhlK;hvdB*  
    count = 0 62y
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    While GetOperationCount(eID)>count lNl.lI\t)y  
        GetOperation eID, count, op ]cVDXLj$  
        If op.Type="ShiftZ" Then S\Le;,
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            DeleteOperation eID,count bf{_U%`  
            count=count-1 sLXM$SMBh  
        End If zmL VFGnS  
        count=count+1 d2^/  
    Wend *<6dB#' J  
    op.Type = "ShiftZ" y6x./1Nb}<  
    op.val1 = taq-0.01 p .P#S  
    op.parent = parID 5h0Hk<N  
    AddOperation eID, op 7J ?s&x  
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    Print "Set pupil diameter = " & pupilDiam Z @ef2y;  
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    'Update AZ Eye subassembly Description T?6<1n
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    eID = FindFullName( "Geometry.Arizona Eye" ) " a,4E{7  
    GetEntity eID, entity 1~3dX[&  
    entity.Description = "Accommodation = " & A & "D" >VQLC&u(  
    SetEntity eID, entity a1/+C$ oB  
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    Update DuDt'^]  
    Print "DONE!" OLm@-I*  
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End Sub =5V7212  
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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/-EVCHr y  
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Accommodation = 4 Diopters -!O8V  
Pupil Diameter = 4 mm +zq"dj_  
Set aqueous humor thickness = 2.81 $p&eS_f  
Set anterior lens radius = 10.4 and conic constant = -2.375869 /h.{g0Xc  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 _)!*,\*`{  
Set lens thickness = 3.927 A9u>bWIE7  
Set lens index of refraction = 1.42672 9y;}B y  
Set pupil diameter = 4 .=t:Uy  
DONE! 
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