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    [技术]Arizona眼睛模型 [复制链接]

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    离线infotek
     
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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 \`x'g)z(i  
    -|mRJVl8  
    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。 hR{Zh>  
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    模型 ,iy   
    zD|W3hL2&  
    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。 |-<L :%  
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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. Z2 4 m  
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    光源 Aed"J5[a  
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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。 sP7(1)\  
    "f+2_8%s+  
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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。 &n wg$z{Y  
    c i>=45@J  
    在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 <hdCO< 0(  
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    图2. 字母F光源的设定方法光 @YELqUb*  
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    图3. 字母F在视网膜上位置点列图
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    视网膜的散射 ualtIHXK)  
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    在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 hd' n"  
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    图4. 视网膜朗伯散射设定
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    注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 /j As`"U  
    5[k35 c{  
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    图5. 视网膜重点采样规格设定
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    脚本 u1l#k60  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: Ns_d10rZ.  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
    vP!gLN]TV  
    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 *k -UQLJ  
    余下的脚本计算与屈光度有关的所有参数。 hv6>3gbr  
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    分析 K"61i:F  
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ns-x\B?^  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 _=b[b]Ec$s  
    ' BpRiN  
    Option Explicit     'Remove this to enable non-dimensioned variables to be used. 2#!D"F  
    0ro+FJ r  
    Dim entity As T_ENTITY jiat5  
    Dim op As T_OPERATION R\^tr  
    Dim mat As T_MODELMATERIAL o <y7Ut  
    Dim A As Double QXCI+Fcg  
    Dim pupilDiam As Double Qa=;Elp:[  
    Dim eID As Long !VW#hc \A5  
    Dim parID As Long o,L!F`W  
    Dim count As Integer 7@\iBmr6  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double sx;1V{|g  
    Dim tlens As Double, nlens As Double (Jm_2CN7X  
    Dim curv As Double, conic As Double 3c)LBM  
    Dim ok As Long  6O}r4*  
    B!Y;VdX  
    Sub Main fXN;N&I  
    LS`Gg7]S  
        '用户输入对话框 4s~o   
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 &AzA0r&,  
            TextBox 220,21,40,21,.TextBox1 'default: 0 X!m/I i$q  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 BmZd,}{  
            OKButton 40,91,90,21 d;z`xy(C  
            CancelButton 190,91,90,21 lPH]fWt<  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Z`D#L[z$  
            TextBox 220,49,40,21,.TextBox2 'default: 4 TUT>*  
        End Dialog }.#C9<"}  
        Dim dlg As UserDialog xGqZ8v`v  
    yR&E6o.$z  
        ok = Dialog (dlg) $ _zdjzT  
    ?w.Yx$Z"  
        If ok=0 Then    'cancel button was pressed 2 IGAZ%%  
            Print "Execution cancelled." B}vI<?c  
            End ?@ O[$9y  
        End If +XsY*$O  
    vR-/c  
        'Assign accommodation and pupil diameter & use defaults if field left empty $ysC)5q.  
        If dlg.TextBox1 = "" Then c7'Pzb)'  
            A = 0           'Default accommodation .gB#g{5+J  
        Else (g 8K?Q  
            A = CDbl(dlg.TextBox1) [mhY_Hmz]  
        End If XG0,@Ly  
    ! !9V0[  
        If dlg.TextBox2 = "" Then `Tab'7  
            pupilDiam = 4   'Default pupil diameter mesR)fTI  
        Else 8u>E(Vmpu  
            pupilDiam = CDbl(dlg.TextBox2) +m"iJW0  
        End If RtSk;U1  
    1iUy*p65:  
        Print " " {pVD`#Tl[  
        Print "Accommodation = " & A & " Diopters" _vad>-=D*U  
        Print "Pupil Diameter = " & pupilDiam & " mm" E@?jsN7  
    DY1o!thz)  
        ' Calculate new parameters with accommodation $Uzc  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness X{)M}WO+r  
    46*?hA7@r(  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens _:{XL c  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens )UWE.o BI  
    #CM2FN:W  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens mFT[[Z#  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens c| E  
    oYu5]ry  
        tlens = 3.767 + 0.04*A                  'Lens thickness b.$Gc!g  
    MVV<&jho{^  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction $Cte$ jg{;  
    7[Y<5T]  
        'Adjust parameters to account for accommodation %hY+%^k.  
    tL D.e  
        '*************************************************************************  +&|WC2#  
        'Aqueous thickness (Position of Lens) 1<lLE1fk  
        '************************************************************************* J|s4c`=  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 55Jk "V#8  
        GetCustomElement eID, entity U|,VH-#  
    3dXyKi  
        parID = FindFullName( "Geometry.Arizona Eye" ) " 4s,a  
    C0'Tua'  
        ' Delete any shift(s) in z S53[K/dZo  
        count = 0 d"$ \fL  
        While GetOperationCount(eID)>count F`'e/  
            GetOperation eID, count, op vQztD _bX%  
            If op.Type="ShiftZ" Then =8[HC}s|$  
                DeleteOperation eID,count >hHn{3y  
                count=count-1 -8g ;t3z  
            End If ]U]{5AA6  
            count=count+1 &FGz53fd4  
        Wend 7)~/`w)P  
    lv,<[Hw1  
        'Set new shift in >pr{)bp G  
        op.Type = "ShiftZ" W*gu*H^s~  
        op.val1 = taq |Zz3X  
        op.parent = parID QO0T<V  
        AddOperation eID, op }56"4/  Z  
        Print "Set aqueous humor thickness = " & taq-0.55 H=EvT'g  
    !DD|dVA{  
        '************************************************************************* Ju+r@/y%  
        'Radius and conic constant of anterior lens #AE'arT<  
        '************************************************************************* .BZw7 YV  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 87y$=eZ  
        GetConic eID, entity, curv, conic 9J*m!-hOY  
    ^KmyB6Yg  
        SetConic eID, entity, 1/Rant, CCant #}l }1^$  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant SxNs  
    taw #r  
        '************************************************************************* db4Ol=  
        'Radius and conic constant of posterior lens ,Epg&)wC]  
        '************************************************************************* (',G Ako  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) u JGYXlLE  
        GetConic eID, entity, curv, conic XswEAz0=  
    %=%jy  
        SetConic eID, entity, 1/Rpost, CCpost [[ H XOPaV  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ^<7)w2ns  
    > PfYHO  
        '************************************************************************* }B^KV#_{S  
        'Lens thickness (Position of posterior lens surface) Jy{A1i@4~s  
        '************************************************************************* a'rN&*P  
    | \C{R  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) qVx0VR1:  
    >cQ*qXI0  
        ' Delete any z-shift(s) =D<46T=(RB  
        count = 0 Ay/ "2pDZ  
        While GetOperationCount(eID)>count ~\(U&2t  
            GetOperation eID, count, op =k'3rm*ld  
            If op.Type="ShiftZ" Then 0 ; M+8  
                DeleteOperation eID,count ?E=&LAI#  
                count=count-1 tNoo3&  
            End If w*OZ1|  
            count=count+1 3;@t {rIin  
        Wend Wl?*AlFlk  
    GjfY   
        'Set new z-shift 7{2knm^  
        op.Type = "ShiftZ" 52,pCyU  
        op.val1 = tlens ma?$@ ]`k  
        op.parent = parID 4L(axjMYU  
        AddOperation eID, op mM&H; W  
        Print "Set lens thickness = " & tlens V.>'\b/#  
    z{7&=$  
        '************************************************************************* s'J8E+&5  
        'Lens index of refraction  \|L@  
        '************************************************************************* A !x" *  
        eID = FindMaterial( "Lens" ) eOE7A'X   
        GetModelMaterial eID, mat A!x_R {,yH  
    %DbL|;z1  
        mat.Nd = nlens >x eKO 2o  
        SetModelMaterial eID, mat L Lm{:T7  
        Print "Set lens index of refraction = " & nlens ?S36)oZzg  
    [j`It4^nC  
        '************************************************************************* i\ X Ok!  
        'Pupil diameter 3W5|Y@0  
        '************************************************************************* % Lhpj[C  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) GTyS8`5E*  
    1.4]T, `  
        'Adjust pupil diameter (trimming volume inner hole) { %vX/Ek  
    ~6Vs>E4G  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" (&=-o(  
    P*BA  
        ' Adjust pupil location to just in front of the lens 5rr7lw WZ  
        parID = FindFullName( "Geometry.Arizona Eye" ) ]3BTL7r  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) =hH>]$J[  
        count = 0 y4tM0h  
        While GetOperationCount(eID)>count ;^^u_SuH  
            GetOperation eID, count, op Hl8-1M$&  
            If op.Type="ShiftZ" Then b54<1\&  
                DeleteOperation eID,count n{6XtIoYq  
                count=count-1 s*>s;S?{|  
            End If *RD9 gIze  
            count=count+1 [-x~Q[  
        Wend P>+{}c}3I  
        op.Type = "ShiftZ" be|k"s|6)  
        op.val1 = taq-0.01 MS)#S&  
        op.parent = parID h/ ?8F^C#v  
        AddOperation eID, op 47ppyh6@  
    S#8wnHq  
        Print "Set pupil diameter = " & pupilDiam ),(ejRP'r  
    MRwls@z=  
        'Update AZ Eye subassembly Description EW%%W6O6  
        eID = FindFullName( "Geometry.Arizona Eye" ) `(vgBz`e[  
        GetEntity eID, entity O[+S/6uy  
        entity.Description = "Accommodation = " & A & "D" +y!dU{L^  
        SetEntity eID, entity j7K9T  
    fIu5d6;'  
        Update Ek~Qp9B  
        Print "DONE!" r :{2}nE  
         bae .?+0[  
    End Sub 5)+(McJC  
    mT <4@RrB  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: [ dpd-s  
    Kn SXygT  
    Accommodation = 4 Diopters gbL99MZ@~  
    Pupil Diameter = 4 mm (YVl5}V  
    Set aqueous humor thickness = 2.81 \bw71( Q  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 S7N3L."  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 hZ Gr/5f  
    Set lens thickness = 3.927 2f9~:.NgF  
    Set lens index of refraction = 1.42672 #O6SEK|Z  
    Set pupil diameter = 4 kj~)#KDN  
    DONE! (cAv :EKpo  
     
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