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infotek 2022-02-25 09:52

Arizona眼睛模型

简介 jw#'f%*  
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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。 u`K+0^)T`  
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模型 3(6i6 vV  
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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。 t'0r4&\  
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. F!j@b!J8  
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光源 HIi"zo=V  
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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。 <}N0 y*m  
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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。 )v8;\1`s:  
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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。 qV8;;&8r  
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图2. 字母F光源的设定方法光 e +4p__TmZ  
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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 Yca9G?^\v  
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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。 Vg6?a  
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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。 X#1So.}c  
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图5. 视网膜重点采样规格设定
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脚本 u#la+/   
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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: : gv[X  
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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。 N, ;'oL+  
余下的脚本计算与屈光度有关的所有参数。 "p2 $R*ie  
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分析 p0`Wci  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ?VS {,"X  
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图7. 字母F在视网膜上颜色分析
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脚本代码 n*@^c$&P  
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  1. Option Explicit     'Remove this to enable non-dimensioned variables to be used. =n9adq  
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    Dim entity As T_ENTITY E' JVf%)  
    Dim op As T_OPERATION 7+#^:;19`  
    Dim mat As T_MODELMATERIAL IP&En8W+  
    Dim A As Double CHN!o9f  
    Dim pupilDiam As Double N;Hrc6nin^  
    Dim eID As Long 4h:Oo  
    Dim parID As Long }_@cqx:n^  
    Dim count As Integer REQ2pfk0  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ,'={/)c<  
    Dim tlens As Double, nlens As Double ~W%A8`9  
    Dim curv As Double, conic As Double m\"M`o B  
    Dim ok As Long gC<\1AIu  
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    Sub Main p^5B_r:  
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        '用户输入对话框 @<W"$_ r-  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 dH#S69>  
            TextBox 220,21,40,21,.TextBox1 'default: 0 "&Q-'L!M'/  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 s3/->1#i  
            OKButton 40,91,90,21 mr E^D|  
            CancelButton 190,91,90,21 H Y.,f_m  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 onG,N1`+  
            TextBox 220,49,40,21,.TextBox2 'default: 4 :NA cad  
        End Dialog {~b]6}O  
        Dim dlg As UserDialog q+WOnTS  
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        ok = Dialog (dlg) )amdRc  
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        If ok=0 Then    'cancel button was pressed A9p$5jt7  
            Print "Execution cancelled." 1PjSa4  
            End #s(B,`?N  
        End If P,_GTs3/G  
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        'Assign accommodation and pupil diameter & use defaults if field left empty 8kH'ai  
        If dlg.TextBox1 = "" Then ?u'JhZ  
            A = 0           'Default accommodation ,XI,B\eNk  
        Else .fU qsq  
            A = CDbl(dlg.TextBox1) K )KE0/ n  
        End If \>23_d0  
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        If dlg.TextBox2 = "" Then i*9eU*i|H  
            pupilDiam = 4   'Default pupil diameter a!Z,~ V8  
        Else wV W+~DJ  
            pupilDiam = CDbl(dlg.TextBox2) ;vQ7[Pv.j  
        End If B%^B_s  
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        Print " " &nZ=w#_  
        Print "Accommodation = " & A & " Diopters" 2ZNTg@o  
        Print "Pupil Diameter = " & pupilDiam & " mm" ~Jp\'P7*  
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        ' Calculate new parameters with accommodation n KDX=73  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness bveNd0hN  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens QIBv}hgcy  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 7{."Y@  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens yY`<t  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens hh <=D.u  
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        tlens = 3.767 + 0.04*A                  'Lens thickness <3Co/.VQd  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction  6>Lr  
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        'Adjust parameters to account for accommodation VSmshld  
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        '************************************************************************* )q&uvfQ1(  
        'Aqueous thickness (Position of Lens) 'u_'y  
        '************************************************************************* ,)S|%tDW  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) DH)@8)C  
        GetCustomElement eID, entity oKA8)~Xqou  
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        parID = FindFullName( "Geometry.Arizona Eye" ) &wK%p/?  
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        ' Delete any shift(s) in z ,t*#o&+  
        count = 0 @e$z Ej5  
        While GetOperationCount(eID)>count lwQI 9U[O2  
            GetOperation eID, count, op $N+a4  
            If op.Type="ShiftZ" Then LPO3B W  
                DeleteOperation eID,count H.|FEV@  
                count=count-1 (!W:-|[K\  
            End If _4xX}Z;  
            count=count+1 | 1T2<ZT  
        Wend %I&Hx<H j  
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        'Set new shift in `<b 3e(A  
        op.Type = "ShiftZ" h+t{z"Ic=  
        op.val1 = taq !yG{`#NZZ  
        op.parent = parID 3xp%o5K  
        AddOperation eID, op D!TS/J1S;u  
        Print "Set aqueous humor thickness = " & taq-0.55 `:-{8Vo7  
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        '************************************************************************* ?9OiF-:n  
        'Radius and conic constant of anterior lens hi`\3B  
        '************************************************************************* -P(q<T2MV'  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) T% Kj >-  
        GetConic eID, entity, curv, conic v?-pAA)ht  
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        SetConic eID, entity, 1/Rant, CCant j:O=9  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant }yK_2zak5i  
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        '************************************************************************* !@W1d|{lu  
        'Radius and conic constant of posterior lens &r/a\t,8n  
        '************************************************************************* Beiz*2-}a  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) {S'xZ._=  
        GetConic eID, entity, curv, conic A_CEpG]  
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        SetConic eID, entity, 1/Rpost, CCpost ZiSy&r:(  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ;rV0  
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        '************************************************************************* ]lXTIej`dy  
        'Lens thickness (Position of posterior lens surface) *&% kkbA  
        '************************************************************************* N6Vn/7I5%  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) TsfOod   
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        ' Delete any z-shift(s) O-U_Zx0zd  
        count = 0 \3O#H  
        While GetOperationCount(eID)>count \2L%%M  
            GetOperation eID, count, op .px*.e s  
            If op.Type="ShiftZ" Then m!$"-nh9  
                DeleteOperation eID,count s@jzu  
                count=count-1 OzA"i y  
            End If ,fT5I6l  
            count=count+1 H9x xId?3u  
        Wend `Ft.Rwj2:m  
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        'Set new z-shift q/6d^&  
        op.Type = "ShiftZ" <DvpqlT  
        op.val1 = tlens ;Tvy)*{  
        op.parent = parID =L 7scv%i  
        AddOperation eID, op 8]YFlW9  
        Print "Set lens thickness = " & tlens "6gu6f  
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        '************************************************************************* V+nqQ~pJ&  
        'Lens index of refraction 0"ZB|^c=  
        '************************************************************************* V2u^sy  
        eID = FindMaterial( "Lens" ) :eo2t>zF-<  
        GetModelMaterial eID, mat Hd U1gV>  
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        mat.Nd = nlens k =ru) _$2  
        SetModelMaterial eID, mat QukLsl]U  
        Print "Set lens index of refraction = " & nlens so9h6K{qcp  
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        '************************************************************************* ([qw#!;w;  
        'Pupil diameter B;SYO>.W  
        '************************************************************************* Ja4O*C<  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) JrQd7  
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        'Adjust pupil diameter (trimming volume inner hole) _Su? VxU  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" pfe9 n[  
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        ' Adjust pupil location to just in front of the lens Zoh2m`6  
        parID = FindFullName( "Geometry.Arizona Eye" ) xm6=l".%z  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) J)6RXt*!  
        count = 0 +`r;3kH ..  
        While GetOperationCount(eID)>count Egi<m   
            GetOperation eID, count, op )|~pocXt<  
            If op.Type="ShiftZ" Then razVO]]E  
                DeleteOperation eID,count wcspqC"_  
                count=count-1 w`bojM@e1  
            End If )V*Z|,#no  
            count=count+1 fLa 7d?4  
        Wend ;[R{oW Nw  
        op.Type = "ShiftZ" r{pTM cDS  
        op.val1 = taq-0.01 I8d#AVF2  
        op.parent = parID 9KN75<n  
        AddOperation eID, op ex @e-<  
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        Print "Set pupil diameter = " & pupilDiam ryy".'v  
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        'Update AZ Eye subassembly Description i(Cd#1<  
        eID = FindFullName( "Geometry.Arizona Eye" ) 6 D_3Hwrs  
        GetEntity eID, entity z4D[>2*  
        entity.Description = "Accommodation = " & A & "D" g)u ~GA*=  
        SetEntity eID, entity \{ r%.G  
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        Update OGw =e{  
        Print "DONE!" ftw\oGrS  
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    End Sub YDE;mIW  
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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: Q&}`( ]k  
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    Accommodation = 4 Diopters Q|q.~x<RQ  
    Pupil Diameter = 4 mm 7%) F]  
    Set aqueous humor thickness = 2.81 J+r\EN^9  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 6nV]Ec~3[  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 >T[1=;o]  
    Set lens thickness = 3.927 DF|(CQs9  
    Set lens index of refraction = 1.42672 |_@ '_  
    Set pupil diameter = 4 Oz<{B]pEul  
    DONE!
silence唯爱 2022-02-25 13:53
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