[技术]Arizona眼睛模型 [复制链接]

简介
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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。 >}~#>Ru  
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模型 2c<&eX8"  
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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。 N-lGa@ j  
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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. -3Avs9`5  
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光源 d-bqL:/  
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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。 E< 4l#Z<  
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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。 0YH+B
 
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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。 j^`X~gE  
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视网膜的散射 W-RqN!snJ8  
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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。 "wH)mQnd  
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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。 +y[@T6_  
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脚本 >-T`0wI  
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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： {s,+^7  
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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。 y#ON|c /  
余下的脚本计算与屈光度有关的所有参数。 3HG;!D~m;  
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分析 ,Y_{L|: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。 W!$zXwY}(  
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脚本代码 hRaf#  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. qOCJTOg7  
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Dim entity As T_ENTITY 4}v@C|.p  
Dim op As T_OPERATION bTmL5}n  
Dim mat As T_MODELMATERIAL @b&84Gn2 r  
Dim A As Double !}TMiCK  
Dim pupilDiam As Double ~ <0Z>qr  
Dim eID As Long oR+-+-??$  
Dim parID As Long {B$2"q/~  
Dim count As Integer $KV&\Q3\0  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double n[xkSF^)  
Dim tlens As Double, nlens As Double xIbMs4'iEx  
Dim curv As Double, conic As Double X[C3&NX#_  
Dim ok As Long 6@;ha=[+  
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Sub Main ZU'!iU|8  
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    '用户输入对话框 l'4AF| p
 
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 yT /EHmJ  
        TextBox 220,21,40,21,.TextBox1 'default: 0 A Ayv  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 noVa=aU^  
        OKButton 40,91,90,21 suJ_nb  
        CancelButton 190,91,90,21 Y,z??bm~J  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Lrz3  
        TextBox 220,49,40,21,.TextBox2 'default: 4 H(u+#PIIw  
    End Dialog Hy
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    Dim dlg As UserDialog /4S;QEv  
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    ok = Dialog (dlg) ;Kxbg>U  
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    If ok=0 Then    'cancel button was pressed c|p,/L09L  
        Print "Execution cancelled." S*W;%J5  
        End jrJR1npB  
    End If sPYX~G&T  
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    'Assign accommodation and pupil diameter & use defaults if field left empty M.%shrJ/  
    If dlg.TextBox1 = "" Then PB'0?b}fab  
        A = 0           'Default accommodation _"f :`  
    Else  <dR,'
 
        A = CDbl(dlg.TextBox1) y%BX]~  
    End If g#^|oYuH6  
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    If dlg.TextBox2 = "" Then r((Tavn  
        pupilDiam = 4   'Default pupil diameter 0A$SYF$O+[  
    Else B+VuUt{S  
        pupilDiam = CDbl(dlg.TextBox2) z MdC  
    End If 60B-ay0e$b  
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    Print " " 97~K!'/^+y  
    Print "Accommodation = " & A & " Diopters" :xeLt;  
    Print "Pupil Diameter = " & pupilDiam & " mm" <bmLy_":  
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    ' Calculate new parameters with accommodation Ueyw;Y  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness =V$j6  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens )q^ Bj$  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ~uaP$*B[  

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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens D&{ *AH%Q  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens tB6k|cPC  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 3{J.xWB@:  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction /A(NuB<Pq  
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    'Adjust parameters to account for accommodation 2"/yEg*=  
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    '************************************************************************* rY70^<z  
    'Aqueous thickness (Position of Lens) 2R@%Y/  
    '************************************************************************* H^(L90  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) F>Jg~ FD*  
    GetCustomElement eID, entity 1kFjas`g  
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    parID = FindFullName( "Geometry.Arizona Eye" ) MV936  
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    ' Delete any shift(s) in z =HE m)  
    count = 0 ,b'4CF  
    While GetOperationCount(eID)>count l
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        GetOperation eID, count, op :c4kBl%gJ  
        If op.Type="ShiftZ" Then 'U)8rR  
            DeleteOperation eID,count K5flit4-  
            count=count-1 9YC&&0 C@  
        End If Yo2Trh  
        count=count+1 olty4kGD$V  
    Wend @-6?i)  
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    'Set new shift in a-PGW2G  
    op.Type = "ShiftZ" YFx=b!/s  
    op.val1 = taq njMLyT($  
    op.parent = parID 5u,sx664  
    AddOperation eID, op YvTA+yL  
    Print "Set aqueous humor thickness = " & taq-0.55 xH$%5@~  
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    '************************************************************************* <o@)SD~K  
    'Radius and conic constant of anterior lens X<xqT  
    '************************************************************************* *Mi6  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) |R~;&x:  
    GetConic eID, entity, curv, conic 37>MJ  
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    SetConic eID, entity, 1/Rant, CCant $FCw$+w  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 
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    '************************************************************************* kPJ~X0Fr{t  
    'Radius and conic constant of posterior lens b\L)m (  
    '************************************************************************* hEcYpng~  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) %+8  
    GetConic eID, entity, curv, conic # U`&jBU  
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    SetConic eID, entity, 1/Rpost, CCpost eC
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    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost @Z2/9K%1'  
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    '************************************************************************* <4NQL*|>  
    'Lens thickness (Position of posterior lens surface) b-b;7a\N  
    '************************************************************************* w:R]!e_6\9  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) !:J<pWN"  
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    ' Delete any z-shift(s) *]9XDc]{j1  
    count = 0
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    While GetOperationCount(eID)>count 2V<# Y  
        GetOperation eID, count, op 2o}8W7y  
        If op.Type="ShiftZ" Then )fR1n}#  
            DeleteOperation eID,count b
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            count=count-1 nK:`e9ES  
        End If EQ~I'#m7  
        count=count+1 d.1Q~&`  
    Wend bgXc_>T6_y  
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    'Set new z-shift Sl~C0eO  
    op.Type = "ShiftZ" bl9E&B/  
    op.val1 = tlens =z%s8D2  
    op.parent = parID mZ&]  
    AddOperation eID, op /K&wr6  
    Print "Set lens thickness = " & tlens ,,2_/u\"/i  
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    '************************************************************************* u"joCZ7`kG  
    'Lens index of refraction >hesxC!  
    '************************************************************************* 3?6Ber y=  
    eID = FindMaterial( "Lens" ) h@/>?Va  
    GetModelMaterial eID, mat !j'guT&9]  
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    mat.Nd = nlens BC&^]M  
    SetModelMaterial eID, mat ;WPI+`-  
    Print "Set lens index of refraction = " & nlens IT7:QEfKU  
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    '************************************************************************* |O^V)bZmx  
    'Pupil diameter w7[
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    '************************************************************************* .;}pU!S~R  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ^W{eO@  
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    'Adjust pupil diameter (trimming volume inner hole) _4De!q0(  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" $M%}Oz3*  
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    ' Adjust pupil location to just in front of the lens uFa-QG^Y{  
    parID = FindFullName( "Geometry.Arizona Eye" ) %k~C-+  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) |O'Hh7  
    count = 0 l$qmn$Uc  
    While GetOperationCount(eID)>count fG^7@Jw:G  
        GetOperation eID, count, op <kk'v'GW@  
        If op.Type="ShiftZ" Then `jt(DKB+J  
            DeleteOperation eID,count !WDn7j'A  
            count=count-1 VdYOm  
        End If +._f.BRmX.  
        count=count+1 J78Qj[v  
    Wend "otr+.{`*  
    op.Type = "ShiftZ" yzODF>KJ  
    op.val1 = taq-0.01 puk4D  
    op.parent = parID 3<yCe%I:  
    AddOperation eID, op ',<{X(#(  
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    Print "Set pupil diameter = " & pupilDiam nT(!HD
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    'Update AZ Eye subassembly Description 6i55Ja  
    eID = FindFullName( "Geometry.Arizona Eye" ) BD<rQmfA^  
    GetEntity eID, entity K4BTk!  
    entity.Description = "Accommodation = " & A & "D" 3
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    SetEntity eID, entity kvY} yw7  
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    Update Ul7,k\q@  
    Print "DONE!" B>c
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End Sub 8kKRx  
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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： <5C=i:6%  
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Accommodation = 4 Diopters ;w>Q{z  
Pupil Diameter = 4 mm &^"s=g.  
Set aqueous humor thickness = 2.81 :cIu?7A  
Set anterior lens radius = 10.4 and conic constant = -2.375869 R A-^!4tX  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 :C}KI)  
Set lens thickness = 3.927 OpbszSl"y  
Set lens index of refraction = 1.42672 <<~lV5  
Set pupil diameter = 4 >&4I.nA  
DONE! y81#UD9[