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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 IkGfnXJ  
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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。 e=+?K5q{P(  
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    模型 #3+!ee27#  
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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。 s;6CExH  
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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. id1s3b;  
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    光源 <c2'0I >  
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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。 #~<0t(3Q  
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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。 <|SRe6m  
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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。 j4cwI90=  
    ~2gG(1%At9  
    图2. 字母F光源的设定方法光 ,uSQNre\j  
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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 }<9cL'  
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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。 YJJB.hR+  
    "gDb1h)8  
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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。 'qOREN  
    5'X ]k@m_  
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    图5. 视网膜重点采样规格设定
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    脚本 v5QqS8u_C  
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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: !BOY@$Y  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
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    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 -T[lx\}  
    余下的脚本计算与屈光度有关的所有参数。 ^$'z!+QRM  
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    分析  y"H*%]  
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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。 /XzH?n/{R  
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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 LQngK7>  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. !U'QqnT  
    ,^eYlmT>6  
    Dim entity As T_ENTITY aD=A^ktx  
    Dim op As T_OPERATION DUC#NZgw  
    Dim mat As T_MODELMATERIAL C'o64+W^  
    Dim A As Double vM*($qpAy  
    Dim pupilDiam As Double OslL~<  
    Dim eID As Long / ;,Md,p  
    Dim parID As Long \ytJ=0r  
    Dim count As Integer @jsDq Ln  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double VBcy9|lD  
    Dim tlens As Double, nlens As Double :$m}UA-9  
    Dim curv As Double, conic As Double =1Oj*x@*4  
    Dim ok As Long C ihAU"  
    }l],.J\BGX  
    Sub Main R}4So1  
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        '用户输入对话框 Pl"Nus   
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 JAQb{KefdO  
            TextBox 220,21,40,21,.TextBox1 'default: 0 S/ODq L|  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 %Ntcvp)  
            OKButton 40,91,90,21 uoX:^'q   
            CancelButton 190,91,90,21 \8?Tdx=  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 C0}IE,]  
            TextBox 220,49,40,21,.TextBox2 'default: 4 :qIXY/  
        End Dialog RWg No #<  
        Dim dlg As UserDialog EioB%f3  
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        ok = Dialog (dlg) n 3D;"a3  
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        If ok=0 Then    'cancel button was pressed 2gq9k}38  
            Print "Execution cancelled." |,!IZ- th  
            End lJis~JLd`  
        End If ] 0B2# d  
    ),ma_{$N  
        'Assign accommodation and pupil diameter & use defaults if field left empty j{9D{  
        If dlg.TextBox1 = "" Then !VI]oRgP  
            A = 0           'Default accommodation |(q9"  
        Else Y<Fz)dQo  
            A = CDbl(dlg.TextBox1) A#95&kJpy  
        End If 8_ tK4PwP  
    #R.-KUW:  
        If dlg.TextBox2 = "" Then ( 8c9 /7h  
            pupilDiam = 4   'Default pupil diameter .[JYj(p  
        Else =yyp?WmC8  
            pupilDiam = CDbl(dlg.TextBox2) N,;5{y1;J  
        End If 8@2OJ=`[  
    "huFA|`  
        Print " "  oze&  
        Print "Accommodation = " & A & " Diopters" T3pmVl  
        Print "Pupil Diameter = " & pupilDiam & " mm" m/y2WlcRx  
    [3--(#R\}?  
        ' Calculate new parameters with accommodation |>JS!NM I  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness a8 mVFm  
    =MLcm^b  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens \8 h;K>=h  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens KjE+QUa  
    Q&eQQ6b^Ih  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens )_i qAqkS  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens W>p-u6u%E|  
    @Q/-s9b  
        tlens = 3.767 + 0.04*A                  'Lens thickness (C@~3!AVa  
    .On|uC)!  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Lg*B>=  
    pD01,5/  
        'Adjust parameters to account for accommodation naw0$kXTA  
    bdibaN-h  
        '************************************************************************* S4h:|jLUF  
        'Aqueous thickness (Position of Lens) \u>"s   
        '************************************************************************* f1_<G  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 3T}izG]  
        GetCustomElement eID, entity :9_L6  
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        parID = FindFullName( "Geometry.Arizona Eye" ) nCj2N,mT  
    .NvQm]N0.  
        ' Delete any shift(s) in z PUBWZ^63  
        count = 0 'toa@5  
        While GetOperationCount(eID)>count +{W>i;U  
            GetOperation eID, count, op (Xq)py9  
            If op.Type="ShiftZ" Then vL\&6n~M>  
                DeleteOperation eID,count Z<SLc,]^  
                count=count-1 L.1_(3NG  
            End If ( 2n>A D_  
            count=count+1 ^*S)t. "  
        Wend \e'R @  
    C~N/A73gF  
        'Set new shift in "Za >ZRR  
        op.Type = "ShiftZ" MF'$~gxo  
        op.val1 = taq R@6zGZ1  
        op.parent = parID SOi*SwQ8  
        AddOperation eID, op Y<Xz wro0  
        Print "Set aqueous humor thickness = " & taq-0.55 ,XIz?R>;c  
    jp"JafS/E  
        '************************************************************************* l#H#+*F  
        'Radius and conic constant of anterior lens 8&3V#sn'  
        '************************************************************************* 3`B6w$z>(  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) *IY*yR6  
        GetConic eID, entity, curv, conic IuOgxm~Y  
    )6Ny1x+  
        SetConic eID, entity, 1/Rant, CCant bX*Hi#J~A  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant { Q`QX`#  
    =}v}my3y"  
        '************************************************************************* %T)oCjM[\  
        'Radius and conic constant of posterior lens Lv'D^'I  
        '************************************************************************* dz *7gL;7G  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Nv/v$Z{k  
        GetConic eID, entity, curv, conic j^;I3_P  
    N#Zhxu,g!  
        SetConic eID, entity, 1/Rpost, CCpost y6IXdW  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost -#2)?NkeE  
    )YX 'N<[  
        '************************************************************************* 'C:>UlzLy  
        'Lens thickness (Position of posterior lens surface) P  '>SmQ  
        '************************************************************************* |d*&y#kV  
    9XRZ$j}L  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) kIGbG;"_  
    Wo7F  
        ' Delete any z-shift(s) (q4),y<:[  
        count = 0 `S2[5i  
        While GetOperationCount(eID)>count .GsO.#p{  
            GetOperation eID, count, op n%k!vJ)]  
            If op.Type="ShiftZ" Then &g.+V/<[  
                DeleteOperation eID,count 5o6>T!  
                count=count-1 GF>'\@Th  
            End If m^H21P"z  
            count=count+1 L dm?JrU  
        Wend 0MkSf*  
    CMCO}#  
        'Set new z-shift z%e8K(  
        op.Type = "ShiftZ" ~5 *5  
        op.val1 = tlens XP1~d>j  
        op.parent = parID  -Y H<  
        AddOperation eID, op Pp| *J^U 4  
        Print "Set lens thickness = " & tlens .9"Y_/0   
    3nu^l'WQ  
        '************************************************************************* qWx][D"  
        'Lens index of refraction xw3YK!$sIF  
        '************************************************************************* ']>Mp#j  
        eID = FindMaterial( "Lens" ) d ,Y#H0`  
        GetModelMaterial eID, mat o.'g]Q<}UB  
    %^8^yZz  
        mat.Nd = nlens HS.^y x  
        SetModelMaterial eID, mat .{=$!8|&I9  
        Print "Set lens index of refraction = " & nlens x#Q>J"g  
    ec gtUb8K  
        '************************************************************************* gF0q@My~  
        'Pupil diameter V`RNM%Y  
        '************************************************************************* S3@ |Q\*r  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) v $7EvFS  
    9!Ar`Io2@  
        'Adjust pupil diameter (trimming volume inner hole) ]Z oD'-,  
    GQl$yZaK{  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" DF g,Xa#  
    .-IkL |M  
        ' Adjust pupil location to just in front of the lens XO9M_*Va  
        parID = FindFullName( "Geometry.Arizona Eye" ) 9&2Vm;F_  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 1 I*7SkgKv  
        count = 0 ! /NG.Wf  
        While GetOperationCount(eID)>count \T\b NbPn  
            GetOperation eID, count, op d5>H3D{49  
            If op.Type="ShiftZ" Then v\,N5  
                DeleteOperation eID,count 6sE{{,OGB  
                count=count-1 aj"M>zd*}  
            End If RiTa \  
            count=count+1 =Me5ft w  
        Wend yY&3p1AxW]  
        op.Type = "ShiftZ" qBQ`~4s  
        op.val1 = taq-0.01 tBm_YP[  
        op.parent = parID ]/!<PF  
        AddOperation eID, op Z{ u a=0  
    h@@nR(<i  
        Print "Set pupil diameter = " & pupilDiam a3VM '  
    " beQZG  
        'Update AZ Eye subassembly Description !bD@aVf?5  
        eID = FindFullName( "Geometry.Arizona Eye" ) d @*GUmJ  
        GetEntity eID, entity g1UGd  
        entity.Description = "Accommodation = " & A & "D" \(PohwWWo  
        SetEntity eID, entity 1O!/g  
    7]BW[~77  
        Update {\z({Wlb]  
        Print "DONE!" V=X:=  
         TP}h~8 /;  
    End Sub 8 :o<ry  
    ~-#yOu ,w  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: /Ux*u#  
    oM2UzB{(  
    Accommodation = 4 Diopters ZKz,|+X0G  
    Pupil Diameter = 4 mm r,]#b[:.s|  
    Set aqueous humor thickness = 2.81 K 9kUS  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 ~fa(=.h  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 Dgql?+2$  
    Set lens thickness = 3.927 QnI.zq V  
    Set lens index of refraction = 1.42672 5I,gBT|B  
    Set pupil diameter = 4 c.|l-zAeX  
    DONE! WA$>pG5s  
     
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