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    [技术]Arizona眼睛模型 [复制链接]

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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 ysl#Rwt/2  
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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。 kWy@wPqms  
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    模型 `wU['{=  
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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。 ,d&3IhYhD  
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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. (Z[c7  
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    光源 zUZET'Bm9  
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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。 QjG/H0*mP  
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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。 )T^w c:  
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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。 d;wq@ e  
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    图2. 字母F光源的设定方法光 /j4G}  
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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 >~Tn%u<  
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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。 y Rl   
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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。 92A9gY  
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    图5. 视网膜重点采样规格设定
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    脚本 -T{2R:\{  
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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: K<`Z@f3'w  
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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。 ) 5$?e  
    余下的脚本计算与屈光度有关的所有参数。 oQu>Qr{Zp  
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    分析 L3xN#W;m7  
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 -)')PV_+  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 tp7$t#  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. 3 e1-w$z&S  
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    Dim entity As T_ENTITY <4vCx  
    Dim op As T_OPERATION  HB'9&  
    Dim mat As T_MODELMATERIAL DgW@v[#BK=  
    Dim A As Double g H'hA'  
    Dim pupilDiam As Double [R%*C9Y d  
    Dim eID As Long !3k-' ),z&  
    Dim parID As Long ``:[Jr &  
    Dim count As Integer K|-m6!C!7  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ]k7%p>c=B  
    Dim tlens As Double, nlens As Double U), HrI>;  
    Dim curv As Double, conic As Double M 80Q6K  
    Dim ok As Long WH1 " HO  
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    Sub Main M57<e`m  
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        '用户输入对话框 9cP{u$  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 `P !idg*  
            TextBox 220,21,40,21,.TextBox1 'default: 0 *9kg \#  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 O)VcW/  
            OKButton 40,91,90,21 O$m &!J  
            CancelButton 190,91,90,21 xi "3NF%=  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Kd+E]$F_OH  
            TextBox 220,49,40,21,.TextBox2 'default: 4 sfn^R+x4,9  
        End Dialog ~B"HI+:\L  
        Dim dlg As UserDialog np6G~0Y`  
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        ok = Dialog (dlg) mR@d4(:J?  
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        If ok=0 Then    'cancel button was pressed !0Nf`iCQ(  
            Print "Execution cancelled." (ub(0 h0j  
            End &Y=~j?~Xm  
        End If uE9,N$\L_  
    ^?""'1iuQx  
        'Assign accommodation and pupil diameter & use defaults if field left empty 0'pB7^y  
        If dlg.TextBox1 = "" Then a_5s'Dh  
            A = 0           'Default accommodation ?i#x13  
        Else /Z^a, %1  
            A = CDbl(dlg.TextBox1) L@AFt)U  
        End If l_:P |  
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        If dlg.TextBox2 = "" Then r.#r!.6 q  
            pupilDiam = 4   'Default pupil diameter *.>@  
        Else -;_"Y]#  
            pupilDiam = CDbl(dlg.TextBox2) ;2`6eyr  
        End If bs ~P  
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        Print " " ,IboPh&Q78  
        Print "Accommodation = " & A & " Diopters" IMqe(  
        Print "Pupil Diameter = " & pupilDiam & " mm" /}U)|6- B  
    k"DZ"JC  
        ' Calculate new parameters with accommodation #9]2Uixq[  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness =&UE67eK,  
    &>+T*-'  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens [=jZP,b&),  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens  eu$VKLY*  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ]i`Q+q[  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens TCyev[(  
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        tlens = 3.767 + 0.04*A                  'Lens thickness '{ =F/q  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction =Vs?=|r  
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        'Adjust parameters to account for accommodation Oz-/0;1n  
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        '************************************************************************* *'8q?R?7g  
        'Aqueous thickness (Position of Lens) &57~i=A 3  
        '************************************************************************* GZrN,M  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) \X*y~)+K`  
        GetCustomElement eID, entity }9\6!GY0  
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        parID = FindFullName( "Geometry.Arizona Eye" ) w@,p`  
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        ' Delete any shift(s) in z aanS^t0  
        count = 0 QlMLWi  
        While GetOperationCount(eID)>count fG>3gS6&  
            GetOperation eID, count, op 8TB|Y  
            If op.Type="ShiftZ" Then J{\Uw].|0  
                DeleteOperation eID,count GV1Ol^  
                count=count-1 )GG9[%H!  
            End If N80ogio_Tk  
            count=count+1 )YEAk@h@  
        Wend +:jonN9d  
    ya~;Of5  
        'Set new shift in v4|TQ8!wR  
        op.Type = "ShiftZ" I[K4/91  
        op.val1 = taq au50%sA~  
        op.parent = parID v^o`+~i  
        AddOperation eID, op fWEQ vQ  
        Print "Set aqueous humor thickness = " & taq-0.55 %zGv+H?  
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        '************************************************************************* l59\Lo:  
        'Radius and conic constant of anterior lens AeEdqX)  
        '************************************************************************* (,o@/ -o  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) JGvhw,g  
        GetConic eID, entity, curv, conic d]sqj\Q57  
    .gC.T`/m  
        SetConic eID, entity, 1/Rant, CCant L)U*dY   
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant GP4!t~"1  
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        '************************************************************************* dYD;Z<l  
        'Radius and conic constant of posterior lens T$u'+* Xx  
        '************************************************************************* dI%jR&.e;  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ; ,sNRES3  
        GetConic eID, entity, curv, conic n5"oXpcIx  
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        SetConic eID, entity, 1/Rpost, CCpost %JSRC<,a  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost H:hM(m0?q  
    ]\|2=  
        '************************************************************************* n7;jME/!  
        'Lens thickness (Position of posterior lens surface) l9|K,YVW  
        '************************************************************************* {~9HJDcM  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) O0'|\:my  
    lFtEQ '}  
        ' Delete any z-shift(s) !$1qnsz  
        count = 0 AC <2.i_  
        While GetOperationCount(eID)>count QpQ2hNf  
            GetOperation eID, count, op +jF |8  
            If op.Type="ShiftZ" Then P,m+^,  
                DeleteOperation eID,count B6&[_cht  
                count=count-1 ?F]P=S:x  
            End If z6J12tu  
            count=count+1 6 L4\UT r  
        Wend XZ.D<T"  
    oh$"?N7n1  
        'Set new z-shift lq53 xT  
        op.Type = "ShiftZ" `. JW_F)1  
        op.val1 = tlens fgL"\d}  
        op.parent = parID -E6av|c,F  
        AddOperation eID, op >H;m[  
        Print "Set lens thickness = " & tlens 46)[F0,$r  
    -6-rX D  
        '************************************************************************* ) q'D9x9  
        'Lens index of refraction nHbi{,3  
        '************************************************************************* wxK71OH  
        eID = FindMaterial( "Lens" ) %Bm{ctf#)  
        GetModelMaterial eID, mat +-;v+{  
    .?g=mh79(  
        mat.Nd = nlens lU Zj  
        SetModelMaterial eID, mat NVkYm+J#  
        Print "Set lens index of refraction = " & nlens ZMMx)}hS  
    S_Nm?;P  
        '************************************************************************* cu?6\@cD  
        'Pupil diameter }*9F`=%F  
        '************************************************************************* rU9")4sQ  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Wx3DWY;  
    dkEbP*y Xg  
        'Adjust pupil diameter (trimming volume inner hole) <`Fl Igo  
    8g{Mv#b%  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" cu5}(  
    ']2d^'TH  
        ' Adjust pupil location to just in front of the lens *^]  
        parID = FindFullName( "Geometry.Arizona Eye" ) 3v3cK1K@oE  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Y{e,I-"{  
        count = 0 y=\&z&3$  
        While GetOperationCount(eID)>count 9HN&M*}  
            GetOperation eID, count, op 2l V`UIa  
            If op.Type="ShiftZ" Then @+M1M 2@Xz  
                DeleteOperation eID,count ]6v7iuvI  
                count=count-1 :n~Mg{j3  
            End If Z-CA9&4Uh  
            count=count+1 3`SH-"{j%  
        Wend /o$6"~t  
        op.Type = "ShiftZ" 8Wtr,%82  
        op.val1 = taq-0.01 /J-.K*xKt  
        op.parent = parID +ah4 K(+3  
        AddOperation eID, op l8+1{6xP  
    7`L]aRS[  
        Print "Set pupil diameter = " & pupilDiam @~$=96^  
    0[ "CP:u  
        'Update AZ Eye subassembly Description >(n /  
        eID = FindFullName( "Geometry.Arizona Eye" ) z<A8S=s6n  
        GetEntity eID, entity W=S^t_F  
        entity.Description = "Accommodation = " & A & "D" GfP'  
        SetEntity eID, entity EqD@o  
    %<Qv?`B  
        Update F\;l)  
        Print "DONE!" |,n(9Ix  
         f9_Pn'"I  
    End Sub #]i^L;u1A  
    !7]^QdBLY  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: $M-"az]  
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    Accommodation = 4 Diopters ; 1?L  
    Pupil Diameter = 4 mm E<B/5g!  
    Set aqueous humor thickness = 2.81 ,{iMF (Nj  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 $@{ d\@U  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 B[w.8e5  
    Set lens thickness = 3.927 UZiL NKc  
    Set lens index of refraction = 1.42672 0.!vp?  
    Set pupil diameter = 4 .{;RJ:O  
    DONE! :& $v.#  
     
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