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    [转载]FRED运用: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: 2016-02-24
    简介 h ?ia4t  
    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。 no/]Me!j=  
    Ch.T} %  
    模型 y\S7oD(OR  
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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。 H]!y |p  
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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. mhVoz0%1X  
    Gz6GU.IyQy  
    光源 ?X9 =4Z~w  
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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。 ?}]kIK}MC  
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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。 r2](~&i2  
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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。 L$Leo6<3a  
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    图2. 字母F光源的设定方法光 EU@mrm?  
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    图3. 字母F在视网膜上位置点列图
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    视网膜的散射 rgYuF,BT.  
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    在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 p;7 4 +q  
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    图4. 视网膜朗伯散射设定
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    注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 rqFs[1wr>R  
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    图5. 视网膜重点采样规格设定
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    脚本 R_qo]WvR;  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: L@z !,r,  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
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    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 TN %"RL  
    余下的脚本计算与屈光度有关的所有参数。 r$#G%FMv  
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    分析 b66X])+4jE  
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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。 UC1!J =f  
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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 K7hf m%`N  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. Y/S3)o  
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    Dim entity As T_ENTITY p0rwiBC=q  
    Dim op As T_OPERATION Ib2@Wi   
    Dim mat As T_MODELMATERIAL tqQ0lv^J  
    Dim A As Double GVEWd/:X(  
    Dim pupilDiam As Double Idlu1g  
    Dim eID As Long MA+-2pMc|7  
    Dim parID As Long \ZFQ?e,d  
    Dim count As Integer IMGqJc,7  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double R1.sq(z`  
    Dim tlens As Double, nlens As Double Nr"N\yOA/  
    Dim curv As Double, conic As Double ]|N4 #4  
    Dim ok As Long X[Ek'=}  
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    Sub Main B Z?W>'B%$  
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        '用户输入对话框 }Hz-h4Z  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 tHtV[We.:  
            TextBox 220,21,40,21,.TextBox1 'default: 0 #Q3PzDfj  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 #tZf>zrs  
            OKButton 40,91,90,21 e(#IewKp  
            CancelButton 190,91,90,21 qd+[ShrhqZ  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 _GO+fB/Q1  
            TextBox 220,49,40,21,.TextBox2 'default: 4 {1MGb%xW  
        End Dialog zw: C*sY  
        Dim dlg As UserDialog t;!]z-Y>  
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        ok = Dialog (dlg) }[z<iij4  
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        If ok=0 Then    'cancel button was pressed }6J7 <g  
            Print "Execution cancelled." *e<Eu>fW#&  
            End cH;TnuX  
        End If 9>Uq$B  
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        'Assign accommodation and pupil diameter & use defaults if field left empty lB!vF ~A&  
        If dlg.TextBox1 = "" Then ]1?=jlUl  
            A = 0           'Default accommodation Lq-33#n/  
        Else ^$IZLM?E~  
            A = CDbl(dlg.TextBox1) ahtYSz_FM  
        End If o}=.  
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        If dlg.TextBox2 = "" Then UQ3@@:L_  
            pupilDiam = 4   'Default pupil diameter `x} Dk<HF  
        Else N\q)LM !M  
            pupilDiam = CDbl(dlg.TextBox2) `4%;qLxngP  
        End If Px?Ao0)Z,  
    5!AV!A_Jp  
        Print " " :Sc8PLT  
        Print "Accommodation = " & A & " Diopters" fYhR#FVI  
        Print "Pupil Diameter = " & pupilDiam & " mm" \V^*44+ <!  
    \C K(;J  
        ' Calculate new parameters with accommodation Ud#X@xK<h  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness +~d1 ;0l|  
    r!$'!lCR  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens 85D^@{  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens L}W1*L$;<  
    ^Cg^ `n?@b  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens B:-U`CHHQ  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens \2Og>{"U  
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        tlens = 3.767 + 0.04*A                  'Lens thickness 1TNz&=e  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction .G}k/`a  
    dC` tN5  
        'Adjust parameters to account for accommodation 'Y!pY]Z  
    7qg<[  
        '************************************************************************* 5Lsm_"0  
        'Aqueous thickness (Position of Lens) hCM8/Vvx6  
        '************************************************************************* dTN$y\   
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) PK6*}y  
        GetCustomElement eID, entity 0e+W/Tq  
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        parID = FindFullName( "Geometry.Arizona Eye" ) > z=Ou<,  
    z2w;oM$g  
        ' Delete any shift(s) in z +z-[s6q2m  
        count = 0 ~BZXt7DE  
        While GetOperationCount(eID)>count ; 8P_av}C  
            GetOperation eID, count, op c>ad0xce6  
            If op.Type="ShiftZ" Then p jKt:R}  
                DeleteOperation eID,count $PSY:Zz  
                count=count-1 TDlZ!$g(  
            End If $!G`D=  
            count=count+1 V+lRi"m?|  
        Wend Q,.By&  
    '>3`rsu  
        'Set new shift in _Vjpw,  
        op.Type = "ShiftZ" jfUJ37zNZr  
        op.val1 = taq ]9jZndgC  
        op.parent = parID &<au/^F  
        AddOperation eID, op DVI7]+=nV  
        Print "Set aqueous humor thickness = " & taq-0.55 ~TDzq -U)  
    (I4y[jnD  
        '************************************************************************* :peqr!I+K  
        'Radius and conic constant of anterior lens }YQ:6I  
        '************************************************************************* .APVjqG  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) S%kS#U${|  
        GetConic eID, entity, curv, conic D(Qa>B"1  
    :pwa{P  
        SetConic eID, entity, 1/Rant, CCant RqXi1<6j#  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant !!FR[NK  
    Qyz>ZPu}sz  
        '************************************************************************* M% @  
        'Radius and conic constant of posterior lens o{V#f_o  
        '************************************************************************* 14  H'!$  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) R"*R99  
        GetConic eID, entity, curv, conic -vV'Lw(  
    `(!NYx  
        SetConic eID, entity, 1/Rpost, CCpost GR%{T'ZD`  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost dK.R[ aQ  
    EX:{EmaT  
        '************************************************************************* !z MDP/V  
        'Lens thickness (Position of posterior lens surface) cC%j!8!  
        '************************************************************************* [Tb\woU  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) p1D()-  
    ==N` !+  
        ' Delete any z-shift(s) D`Gt  
        count = 0 SK+@HnKd  
        While GetOperationCount(eID)>count @`wn<%o$  
            GetOperation eID, count, op qD-fw-,:  
            If op.Type="ShiftZ" Then -es"0wS<u  
                DeleteOperation eID,count D`VFf\7  
                count=count-1 j0FW8!!-g  
            End If 'T7x@a`b)  
            count=count+1 >,"sHm}l%  
        Wend ;i\C]*  
    rJQ=9qn\  
        'Set new z-shift  H4:ZTl_$  
        op.Type = "ShiftZ" B'}"AC"  
        op.val1 = tlens Nb;H`<JP  
        op.parent = parID b`CWp;6Y  
        AddOperation eID, op #~k[6YR 0  
        Print "Set lens thickness = " & tlens Uoj i@  
    6Y1J2n"  
        '************************************************************************* x=]S.XI  
        'Lens index of refraction ;W{b $k@g  
        '************************************************************************* ewnfeg1  
        eID = FindMaterial( "Lens" ) d~@q%-`lA  
        GetModelMaterial eID, mat r`6:Q&&  
    /v#)f-N%zs  
        mat.Nd = nlens ,Ff n)+  
        SetModelMaterial eID, mat Au.:OeJm  
        Print "Set lens index of refraction = " & nlens *HE^1IEl  
    J8<J8x4  
        '************************************************************************* _KN/@(+F  
        'Pupil diameter 3;_ n{&  
        '************************************************************************* LA4<#KP  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ~W03{9(Vp8  
    rk|@B{CA;  
        'Adjust pupil diameter (trimming volume inner hole) NTmi 2c  
    aV6#t*\J  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" T8XY fcc*h  
    #@qN8J}R  
        ' Adjust pupil location to just in front of the lens pSfYu=#f  
        parID = FindFullName( "Geometry.Arizona Eye" ) *(QH{!-$s  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) uzBz}<M=  
        count = 0 s0C:m  
        While GetOperationCount(eID)>count p[v#EyoC  
            GetOperation eID, count, op WeMAe w/d  
            If op.Type="ShiftZ" Then 3fr^ T  
                DeleteOperation eID,count >w|*ei:@S  
                count=count-1 M#,Q ^rH#  
            End If ".U^if F  
            count=count+1 27D!'S  
        Wend OH6^GPF6  
        op.Type = "ShiftZ" ,gx)w^WTm  
        op.val1 = taq-0.01 PaO- J&<  
        op.parent = parID \we\0@v  
        AddOperation eID, op U BZ9A  
    j9R6ta3\l  
        Print "Set pupil diameter = " & pupilDiam $t/rOo9cV  
    UiQEJXwnz  
        'Update AZ Eye subassembly Description Ug%_@t/?  
        eID = FindFullName( "Geometry.Arizona Eye" ) PmX2[7  
        GetEntity eID, entity DN8}gl VxV  
        entity.Description = "Accommodation = " & A & "D" z[nS$]u  
        SetEntity eID, entity h7yqk4'Lq  
    b]Z@^<_E  
        Update : c.JhE3D  
        Print "DONE!" 06 mlj6hV  
         e8P-k3a"5:  
    End Sub y\c"b-lQX  
    D g>^ A  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: .Y*f2A.v  
    1(#;&:$`i  
    Accommodation = 4 Diopters aM=D84@  
    Pupil Diameter = 4 mm 9X}I>  
    Set aqueous humor thickness = 2.81 jO~:<y3 =  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 1X1 N tS @  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 GK*v{`  
    Set lens thickness = 3.927 , YW|n:X  
    Set lens index of refraction = 1.42672 ,!#ccv+Vm%  
    Set pupil diameter = 4 /JJw 6[ N  
    DONE! kv{}C)kt3  
    &^".2)zU  
    (文章来源:讯技光电)
     
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