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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 |+q_kx@?l  
    |CDM(g>%  
    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。 D<6$@ZJ  
    X$>F78e*  
    模型 T;92M}\  
    v:P]o9Oj8  
    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&ueD& *4&  
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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. x#EE_i/W  
    $&as5z8  
    光源 |reA`&<q  
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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。 o9 9ExQ.  
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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。 =HCEUB9Fs  
    &u2;S?7m  
    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。 2R&\qZ<  
    !i;6!w  
    图2. 字母F光源的设定方法光 m !*F5x  
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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 @:}c(j  
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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。 [Arf!W-QG  
    ='h2z"}\Bn  
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    图4. 视网膜朗伯散射设定
    Y)1/f EM  
    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。 \ASt&'E  
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    图5. 视网膜重点采样规格设定
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    脚本 $X#y9<bW  
    ;7P '>j1?U  
    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: spV7\Gs.@  
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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。 /3ohm|!rW  
    余下的脚本计算与屈光度有关的所有参数。 G,)zn9X  
    #d@wjQ0DW  
    分析 Ol>q(-ea  
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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。 ?@rd,:'dE  
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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 f7x2"&?vg  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. Ek L2nI  
    %+~\I\)1  
    Dim entity As T_ENTITY ]=~dyi  
    Dim op As T_OPERATION 4C*ywP  
    Dim mat As T_MODELMATERIAL [J,.?'V  
    Dim A As Double zS%XmS\  
    Dim pupilDiam As Double OD8 fn  
    Dim eID As Long [~9UsHfH  
    Dim parID As Long h!w::cV  
    Dim count As Integer UMGiJO\yH  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double VhO%4[Jl  
    Dim tlens As Double, nlens As Double g+#awi7  
    Dim curv As Double, conic As Double MKBDWLCB  
    Dim ok As Long &&&-P\3  
    +u$l]~St\  
    Sub Main I){4MoH.  
    4'O,xC  
        '用户输入对话框 b}K,wAx  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 *5feB#  
            TextBox 220,21,40,21,.TextBox1 'default: 0 HA,o2jZ?In  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 q}LDFsU  
            OKButton 40,91,90,21 .ck?JXg  
            CancelButton 190,91,90,21 gQeQy  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ? Lg(,-:  
            TextBox 220,49,40,21,.TextBox2 'default: 4 *~^63Nx!  
        End Dialog c~ R'`Q  
        Dim dlg As UserDialog [M\ an6h6O  
    RIMSXue*Ha  
        ok = Dialog (dlg) ,\M77V  
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        If ok=0 Then    'cancel button was pressed  (Q8!5s  
            Print "Execution cancelled." ;%e)t[5  
            End ?AyxRbk  
        End If ~IhM(Q*mO!  
    tj13!Cc}e`  
        'Assign accommodation and pupil diameter & use defaults if field left empty Xz^nm\  
        If dlg.TextBox1 = "" Then MfL7|b)  
            A = 0           'Default accommodation J0!V(  
        Else RcYUO*  
            A = CDbl(dlg.TextBox1) ]rv\sD`[  
        End If e0`z~z]6&  
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        If dlg.TextBox2 = "" Then ^-"Iw y  
            pupilDiam = 4   'Default pupil diameter b? ); D  
        Else \bARp z?a  
            pupilDiam = CDbl(dlg.TextBox2) A6]:BuP;c  
        End If &ksuk9M  
    >PA*L(Dh%  
        Print " " ,U\ s89  
        Print "Accommodation = " & A & " Diopters" zH]oAu=H  
        Print "Pupil Diameter = " & pupilDiam & " mm" Tx.N#,T|  
    ;I4vPh5Q  
        ' Calculate new parameters with accommodation So 1TH%  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness *)E${\1'<  
    kSz+UMC-7:  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens [.}qi[=n  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens d0>U-.  
    ~[Tcl  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens =ANr|d  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens z x-[@G  
    <U3X4)r  
        tlens = 3.767 + 0.04*A                  'Lens thickness =Kkqk  
    'FXM7D   
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction w % Hj'  
    V}s/knd  
        'Adjust parameters to account for accommodation "u6pl);G  
    H,% bKl#  
        '************************************************************************* (%B{=w}8  
        'Aqueous thickness (Position of Lens) _pTcSp 3  
        '************************************************************************* :Qge1/  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) )gdeFA V  
        GetCustomElement eID, entity A$@;Q5/2  
    cp Ot?XYR~  
        parID = FindFullName( "Geometry.Arizona Eye" ) #Pg#\v|7#>  
    % G= cKM  
        ' Delete any shift(s) in z 6\7c:  
        count = 0 x {NBhq(4  
        While GetOperationCount(eID)>count .) Ej#mk  
            GetOperation eID, count, op hQ|mow@Zmz  
            If op.Type="ShiftZ" Then Ic0Sb7c  
                DeleteOperation eID,count %tVU Rj  
                count=count-1 + +L7*1t  
            End If "&={E{pQ  
            count=count+1 DSLX/u o1  
        Wend =p;cJ%#2]'  
    |Y!^E % *  
        'Set new shift in d ~ M;  
        op.Type = "ShiftZ" )]fiyXA  
        op.val1 = taq *ak0(yLn)  
        op.parent = parID ZD&F ,2v  
        AddOperation eID, op RnH?95n?{  
        Print "Set aqueous humor thickness = " & taq-0.55 L/u|90) L  
    d#T5=5 #  
        '************************************************************************* No7-fX1B  
        'Radius and conic constant of anterior lens  R[m-jUL  
        '************************************************************************* ? $/::uo  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 7rdmj[vu  
        GetConic eID, entity, curv, conic %NkiYiA  
    )xcjQkb  
        SetConic eID, entity, 1/Rant, CCant ;T^s&/>E  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant h ;uzbu  
    )|=1;L  
        '************************************************************************* ^ |MS2'  
        'Radius and conic constant of posterior lens G u`xJ  
        '************************************************************************* @K]`!=vUk  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) +<\LY(o  
        GetConic eID, entity, curv, conic j55_wx@cA  
    4pL'c@'  
        SetConic eID, entity, 1/Rpost, CCpost z- q.8~Z  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 3Ws(],Q  
    }Cu:BD.zQ  
        '************************************************************************* Y7S1^'E 3  
        'Lens thickness (Position of posterior lens surface) o`CM15d*7o  
        '************************************************************************* #K^hKx9  
    5mAb9F8@  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) x;W!sO@$  
    tpS gbGzp  
        ' Delete any z-shift(s) )cH\i91  
        count = 0 XgxO:"B  
        While GetOperationCount(eID)>count p.:|Z-W$  
            GetOperation eID, count, op N #v[YO`.  
            If op.Type="ShiftZ" Then yq.@-]ytZ  
                DeleteOperation eID,count "7sv@I_j  
                count=count-1 Qy9_tvq X  
            End If B9"d7E#wHF  
            count=count+1 l=xG<)Okb  
        Wend q#j[0,^ $  
    L$Z!  
        'Set new z-shift \8#[AD*@s2  
        op.Type = "ShiftZ" ILCh1=?{9r  
        op.val1 = tlens <J d!`$  
        op.parent = parID l'l&Zqd  
        AddOperation eID, op 4 6v C/  
        Print "Set lens thickness = " & tlens fOMaTnm'  
    p{oz}}  
        '************************************************************************* vs8[352  
        'Lens index of refraction -Jd7  
        '************************************************************************* |gV~U~A]  
        eID = FindMaterial( "Lens" ) F+Kju2  
        GetModelMaterial eID, mat OX.5o lb  
    yPmo1|'X>d  
        mat.Nd = nlens \2u7>fU!  
        SetModelMaterial eID, mat &</)k|.A6\  
        Print "Set lens index of refraction = " & nlens 1a9' *[  
    -)%\$z  
        '************************************************************************* Sck!w 3  
        'Pupil diameter Vw ;iE=L  
        '************************************************************************* O=}w1]  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) C+\z$/q  
    ^%*qe5J  
        'Adjust pupil diameter (trimming volume inner hole) A23K!a2u&  
    Hva!6vwO%O  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Zs^zD;zU  
    t _ CMsp  
        ' Adjust pupil location to just in front of the lens (f"Qz~R|6_  
        parID = FindFullName( "Geometry.Arizona Eye" )  @mw1__?  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ecm+33C  
        count = 0 BUZ74  
        While GetOperationCount(eID)>count $Ud9v4  
            GetOperation eID, count, op 53/$8=  
            If op.Type="ShiftZ" Then jA8Bmwt;w  
                DeleteOperation eID,count mmwc'-jU:  
                count=count-1 ;|T|*0vY[  
            End If Kez0Bka  
            count=count+1 s]yZ<uA  
        Wend euY+jc%  
        op.Type = "ShiftZ" w*'DlP<7  
        op.val1 = taq-0.01 \aSc2Ml]3n  
        op.parent = parID <Y /3U  
        AddOperation eID, op 0F uj-q  
    =WN8> <K!  
        Print "Set pupil diameter = " & pupilDiam %D-!< )z  
    `!N.1RP _  
        'Update AZ Eye subassembly Description vy [7I8f{  
        eID = FindFullName( "Geometry.Arizona Eye" ) -DGuaUU  
        GetEntity eID, entity yo5-x"ze  
        entity.Description = "Accommodation = " & A & "D" #U'}g *  
        SetEntity eID, entity CWZv/>,%  
    e8SAjl"}  
        Update \B 8j9  
        Print "DONE!" `?&C5*P  
         "@ZwDg`  
    End Sub LB7$&.m'B  
    @ #J2t#  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: Q_/UC#I8  
    DM6(8df(  
    Accommodation = 4 Diopters 9XUYy2{G  
    Pupil Diameter = 4 mm z+fy&NPl  
    Set aqueous humor thickness = 2.81 l [ m_<1L  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 ;|=5)KE  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 Qt"jU+Zoy  
    Set lens thickness = 3.927 ~A/vP-  
    Set lens index of refraction = 1.42672 Yk{4 3yw  
    Set pupil diameter = 4 Y}}1]}VIK  
    DONE! 1.2qh"#  
     
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