[技术]Arizona眼睛模型 [复制链接]

简介 l)iv\j  
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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。 z-)*Q  
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模型 oEPNN'~3  
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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。 o>$|SU!a  
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在FRED中使用0屈光度来创建的，光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. S].Ft/+H  
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光源 XzlIW&"uC  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 1uY3[Z9S  
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处，并增加了pre-propagation distance= -8。尽管光线在光瞳处创建，规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射，而不是在光瞳处入射。 s?~8O|Mu'  
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在往下看是内置的脚本用来修改屈光度，使其为4（250mm），光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 ,?t}NZY&  
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视网膜的散射 okVp\RC  
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在散射文件中，有一个名为“Retina surface”的72%的反射型朗伯散射，它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射，改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 tu7+LwF7  
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注意在视网膜的表面有散射重点采样规格定义，在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳，半角度10度。 kf}F}Ad:%  
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脚本 Bmi:2} j  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框，如下图所示： 'MSEki67  
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如果“OK”按钮按下，将会核对对话框下面的代码行，如果点击取消则脚本终止。然后输入的参数赋予变量，如果此处是保留为空白，则使用默认值。因此，如果没有值输入并点击“OK”按钮，则脚本是以屈光度为0，光瞳直径为4mm来运行的。 T-hU+(+hg  
余下的脚本计算与屈光度有关的所有参数。 d'x<-l9  
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分析 v&k>0lV,^  
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屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 rSM$E  
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脚本代码 9k714bnMLX  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. i#CaKS  
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Dim entity As T_ENTITY L"Qh_+  
Dim op As T_OPERATION E1$Hu
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Dim mat As T_MODELMATERIAL ;,Of\Efc|  
Dim A As Double ~ >&I^4  
Dim pupilDiam As Double # q0Ub-  
Dim eID As Long MLkL.1eGSb  
Dim parID As Long  #a|6Q
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Dim count As Integer TBoM{s=.  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double +a7EsR  
Dim tlens As Double, nlens As Double B"pFJ"XR  
Dim curv As Double, conic As Double 4iYgs-,  
Dim ok As Long BfD,z  
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Sub Main v_?s
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    '用户输入对话框 $[HcHnf  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Yio>ft&g]  
        TextBox 220,21,40,21,.TextBox1 'default: 0 V6DBKq  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 GnSgO-$"  
        OKButton 40,91,90,21 4jC4X*  
        CancelButton 190,91,90,21 .g6PrhzFbk  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 2eZk3_w  
        TextBox 220,49,40,21,.TextBox2 'default: 4 ]7XkijNb  
    End Dialog h|(ZXCH  
    Dim dlg As UserDialog ?.rH;:9To  
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    ok = Dialog (dlg) fPh}l  
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    If ok=0 Then    'cancel button was pressed 2uJNc!&  
        Print "Execution cancelled." y
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        End
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    End If wW6mYgPN%  

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    'Assign accommodation and pupil diameter & use defaults if field left empty Y
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    If dlg.TextBox1 = "" Then FqT,4SIR  
        A = 0           'Default accommodation
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    Else 2$j Ot}  
        A = CDbl(dlg.TextBox1) E3FW*UNg[y  
    End If .-O@UQx.I  

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    If dlg.TextBox2 = "" Then ?$)x$nS`  
        pupilDiam = 4   'Default pupil diameter Xh7~MU~X  
    Else %-1BA*J`|  
        pupilDiam = CDbl(dlg.TextBox2) y(bt56 | z  
    End If /el["l
 
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    Print " " ]<\;d B  
    Print "Accommodation = " & A & " Diopters" #x4h_K Y  
    Print "Pupil Diameter = " & pupilDiam & " mm" > hDsm;,/  
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    ' Calculate new parameters with accommodation &.+n L  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness jE?\Yv3  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens V#-qKV  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens /A[oj2un  

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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens pjKl)q  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens .%J?T5D  
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    tlens = 3.767 + 0.04*A                  'Lens thickness %X0NHta~@  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction "&~?Hzm  
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    'Adjust parameters to account for accommodation  ^:  
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    '************************************************************************* t=E|RYC(k  
    'Aqueous thickness (Position of Lens) c
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    '************************************************************************* >^a"Z[s[  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) R+kZLOE  
    GetCustomElement eID, entity |=^#d\?]j  
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    parID = FindFullName( "Geometry.Arizona Eye" ) N?2#YTjR  
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    ' Delete any shift(s) in z MWn L#!  
    count = 0 f9l<$l  
    While GetOperationCount(eID)>count "`W1yk5x  
        GetOperation eID, count, op q563,s  
        If op.Type="ShiftZ" Then aaf_3UH.B  
            DeleteOperation eID,count ,SJK  
            count=count-1 g+KzlS[6  
        End If yf#%)-7(  
        count=count+1 O)RzNfI^`N  
    Wend w /W Cj4`  
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    'Set new shift in O"J.k&C<,  
    op.Type = "ShiftZ" ELgae1  
    op.val1 = taq )
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    op.parent = parID QIMv9;  
    AddOperation eID, op <Z_wDK/UR  
    Print "Set aqueous humor thickness = " & taq-0.55 @)2V"FE4i  
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    '************************************************************************* |`(?<m  
    'Radius and conic constant of anterior lens Q~w G(0'8  
    '************************************************************************* 
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    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) H-cBXp5z  
    GetConic eID, entity, curv, conic _E&vE5<-$  
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    SetConic eID, entity, 1/Rant, CCant 'd.@4 9  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ,^+R%7mv  
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    '************************************************************************* PRk%C0`  
    'Radius and conic constant of posterior lens *liPJ29C[  
    '************************************************************************* !^w\$cw&  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) +}-W.H%`0  
    GetConic eID, entity, curv, conic +&N&D"9A  
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    SetConic eID, entity, 1/Rpost, CCpost 0rm;)[SjF  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost syNb0LR  
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    '************************************************************************* ;`of'9|  
    'Lens thickness (Position of posterior lens surface) 9;v"bcQ  
    '************************************************************************* h%w\O Z7  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) &9lc\Y4PY  
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    ' Delete any z-shift(s) yxP?O@(  
    count = 0 K7O?{/  
    While GetOperationCount(eID)>count 4tTZkJc  
        GetOperation eID, count, op vYt:}$AE  
        If op.Type="ShiftZ" Then 8rG&CxI  
            DeleteOperation eID,count [rQ(ae  
            count=count-1 TnU$L3k  
        End If o27`g\gDR,  
        count=count+1 e"adkV  
    Wend qp_ `Fj:  
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    'Set new z-shift YlcF-
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    op.Type = "ShiftZ" N evvA(M  
    op.val1 = tlens 5Kw?SRFH/  
    op.parent = parID L{0OMyUA  
    AddOperation eID, op T17LYHIT  
    Print "Set lens thickness = " & tlens 8`~3MsE"  
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    '************************************************************************* MJ"Mn^:/  
    'Lens index of refraction rU^ghF  
    '************************************************************************* W>|b98NPu  
    eID = FindMaterial( "Lens" ) iM/0Yp-v'>  
    GetModelMaterial eID, mat Isgk  
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    mat.Nd = nlens XK/@!ud"`  
    SetModelMaterial eID, mat K y4y  
    Print "Set lens index of refraction = " & nlens p;t!"I:`?  
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    '************************************************************************* U?^|>cMr  
    'Pupil diameter 8'xnhV  
    '************************************************************************* 4qz{D"M  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) OK J%M]<  
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    'Adjust pupil diameter (trimming volume inner hole) kJeOlO[  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" K':pU1  
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    ' Adjust pupil location to just in front of the lens %dU'$)  
    parID = FindFullName( "Geometry.Arizona Eye" ) KC-aLq/  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) D&m"~wI  
    count = 0 U(]5U^  
    While GetOperationCount(eID)>count }Z?[Ut  
        GetOperation eID, count, op 446hrzW>@  
        If op.Type="ShiftZ" Then .F3LA6se  
            DeleteOperation eID,count <r`Jn49  
            count=count-1 842+KLS  
        End If l<:E+lU  
        count=count+1 !X <n:J  
    Wend ~+nSI-L  
    op.Type = "ShiftZ" Iw|[*Nu-  
    op.val1 = taq-0.01 2^ZPO4|  
    op.parent = parID [=1?CD  
    AddOperation eID, op q<uLBaL_]r  
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    Print "Set pupil diameter = " & pupilDiam oNsx Fi:  
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    'Update AZ Eye subassembly Description p2vUt  
    eID = FindFullName( "Geometry.Arizona Eye" ) (a
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    GetEntity eID, entity mT~>4xi0  
    entity.Description = "Accommodation = " & A & "D" #=#$b_6*  
    SetEntity eID, entity f4I9H0d;!  
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    Update WA\f`SRF  
    Print "DONE!" i4r~eneP
 
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End Sub DmPsltpzQ  
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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： _-\{k
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Accommodation = 4 Diopters h1o+7  
Pupil Diameter = 4 mm B"zg85 e  
Set aqueous humor thickness = 2.81 XRz6Yf(/  
Set anterior lens radius = 10.4 and conic constant = -2.375869 m8^2k2  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 %9Fg1LH42r  
Set lens thickness = 3.927 1AV1W_"  
Set lens index of refraction = 1.42672 6lAo`S\)eX  
Set pupil diameter = 4 l>?vjy65  
DONE! 1H 6Wrik