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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 ^yRCR] oT  
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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。 b>%I=H%g  
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    模型 w9}I*Nra  
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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。 {kJ[)7  
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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. \]J" e%  
    4(JxZ49  
    光源 r/Pg,si  
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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。 ^ d"tymDd  
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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。 !9o8v0ZI  
    :B- ,*@EU  
    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。 !wrl.A/P  
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    图2. 字母F光源的设定方法光 2 ;B[n;Q{  
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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 @V:b Co  
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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。 n?,fF(  
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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。 "<O?KO 3K  
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    图5. 视网膜重点采样规格设定
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    脚本 db%`- UST  
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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: ;pB?8Z  
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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。 OC\C^Yh*U  
    余下的脚本计算与屈光度有关的所有参数。 :,VyOmf  
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    分析 R a*9d]N@  
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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。 +vbNZqwz  
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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 E_yh9lk  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. 9Pb0Olh  
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    Dim entity As T_ENTITY R\+$^G}#6  
    Dim op As T_OPERATION oL6_Ya  
    Dim mat As T_MODELMATERIAL gVl#pVO`N  
    Dim A As Double Aqm0|GlJ  
    Dim pupilDiam As Double Aio0++ r-  
    Dim eID As Long L]tyL)  
    Dim parID As Long T@S+5(  
    Dim count As Integer W@0(Y9jdg  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ]JM9 ^F  
    Dim tlens As Double, nlens As Double "M*\,IH  
    Dim curv As Double, conic As Double 0bd.ess  
    Dim ok As Long $i`YtV  
    $ `ho+  
    Sub Main FQ4rA 4  
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        '用户输入对话框 k4l72 'P  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7vWB=r>5@  
            TextBox 220,21,40,21,.TextBox1 'default: 0 ><DE1tG  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Gce_gZH7{  
            OKButton 40,91,90,21 [lJ[kr*7  
            CancelButton 190,91,90,21 EagI)W!s[  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 U--ER r8  
            TextBox 220,49,40,21,.TextBox2 'default: 4 FPMW"~v  
        End Dialog C/$IF M<  
        Dim dlg As UserDialog %$}iM<  
    C^~iz in  
        ok = Dialog (dlg) BdYh:  
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        If ok=0 Then    'cancel button was pressed bC{~/ JP  
            Print "Execution cancelled." c*W$wr  
            End qjFgy)qV  
        End If f ;Dz(~ hw  
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        'Assign accommodation and pupil diameter & use defaults if field left empty 0'<S7?~|  
        If dlg.TextBox1 = "" Then +l#2u#e  
            A = 0           'Default accommodation npF[J x[  
        Else &0"`\~lA  
            A = CDbl(dlg.TextBox1) 4H:WpW*r  
        End If AX)zSrXn  
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        If dlg.TextBox2 = "" Then _Dv^~e1c  
            pupilDiam = 4   'Default pupil diameter *SW,pHYnLb  
        Else I@B7uFj  
            pupilDiam = CDbl(dlg.TextBox2) 0Nfj}sXCWE  
        End If B+<k,ad  
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        Print " " L9.#/%I\  
        Print "Accommodation = " & A & " Diopters" 4M]8po/;  
        Print "Pupil Diameter = " & pupilDiam & " mm" J B|I/\(A  
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        ' Calculate new parameters with accommodation We ->d |=  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness x0d+cSw  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens d.Z]R&X08  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens UdGoPzN  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens VtO+=mZV  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens {G}HZv%S U  
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        tlens = 3.767 + 0.04*A                  'Lens thickness =T-w.}27O  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 82X.  
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        'Adjust parameters to account for accommodation Trrh`@R  
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        '************************************************************************* P5>CSWy%  
        'Aqueous thickness (Position of Lens) tX251S  
        '************************************************************************* BGX@n#:  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) )hug<D *h  
        GetCustomElement eID, entity | 6>_L6t  
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        parID = FindFullName( "Geometry.Arizona Eye" ) F(<8:`N;G  
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        ' Delete any shift(s) in z Bt,Xe~$z-  
        count = 0 &wN 2l-  
        While GetOperationCount(eID)>count K_QCYS.  
            GetOperation eID, count, op $T6Qg(p  
            If op.Type="ShiftZ" Then C~qhwwh  
                DeleteOperation eID,count vgj^-  
                count=count-1 CWp1)% 0=  
            End If { ZX C%(u  
            count=count+1 L2'd sOn  
        Wend %7msAvbk  
    [.X%:H+  
        'Set new shift in KeB4Pae|V  
        op.Type = "ShiftZ" )\-";?sYky  
        op.val1 = taq 1v&Fo2ML  
        op.parent = parID vC:b?0s#(  
        AddOperation eID, op 'c&@~O;^d  
        Print "Set aqueous humor thickness = " & taq-0.55 +5[oY,^cO  
    5vf t}f  
        '************************************************************************* v9U(sEDq  
        'Radius and conic constant of anterior lens %i8>w:@NW  
        '************************************************************************* abeSkWUL(  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) R*Z]  
        GetConic eID, entity, curv, conic rxj@NwAno  
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        SetConic eID, entity, 1/Rant, CCant *ldMr{s<R  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant W@,p9=425  
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        '************************************************************************* vt@Us\fI  
        'Radius and conic constant of posterior lens Q)`gPX3F  
        '************************************************************************* `uh@iD'KI  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) F,M"/hnPT  
        GetConic eID, entity, curv, conic ,6;xr'[o*  
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        SetConic eID, entity, 1/Rpost, CCpost s;2/Nc   
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost (\t_Hs::a  
    EB5_;  
        '************************************************************************* ny(GTKoUz  
        'Lens thickness (Position of posterior lens surface) ZQ~myqx,+L  
        '************************************************************************* C$LRY~ \  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) rN1U.FRe/  
    HCG@#W<wc  
        ' Delete any z-shift(s) q^1aPz  
        count = 0 =+`j?1  
        While GetOperationCount(eID)>count *Z`XG_s5  
            GetOperation eID, count, op g&+Y{*Gp  
            If op.Type="ShiftZ" Then 7q!yCU  
                DeleteOperation eID,count Mf:M3H%YV+  
                count=count-1 sQ}%7BMK  
            End If l]Ui@X  
            count=count+1 pSQCT  
        Wend /*AJr  
    R+E_#lP_$  
        'Set new z-shift jefNiEE[  
        op.Type = "ShiftZ" LMFK3Gd[  
        op.val1 = tlens Ty3CBR{6  
        op.parent = parID HX3D*2v":  
        AddOperation eID, op wKk 3)@il  
        Print "Set lens thickness = " & tlens cXS;z.M\_  
     O[IR|  
        '************************************************************************* NTm<6Is`  
        'Lens index of refraction CYtjY~  
        '************************************************************************* aGB0-;.t7  
        eID = FindMaterial( "Lens" ) +_ *eu  
        GetModelMaterial eID, mat 4<T*i{[  
    %'L].+$t  
        mat.Nd = nlens cgs3qI  
        SetModelMaterial eID, mat Cf0|Z  
        Print "Set lens index of refraction = " & nlens GS ;HtUQ  
    P>*Fj4 Z~  
        '************************************************************************* M*5,O   
        'Pupil diameter 4>4V-m\  
        '************************************************************************* e9CP802#2  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 0A#*4ap  
    _1>SG2h{fV  
        'Adjust pupil diameter (trimming volume inner hole) 7hB#x]oQo  
    PXw| L  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" WD15pq l  
    P<%v +O  
        ' Adjust pupil location to just in front of the lens wgY6D!Y   
        parID = FindFullName( "Geometry.Arizona Eye" ) EjWgaV  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \un sh^M  
        count = 0 sYGR-:K  
        While GetOperationCount(eID)>count 8y$5oD6g9  
            GetOperation eID, count, op Iq{o-nq  
            If op.Type="ShiftZ" Then O\6vVM[  
                DeleteOperation eID,count -i#J[>=w{C  
                count=count-1 (tepmcf  
            End If NX?}{'f  
            count=count+1 wHx}U M"  
        Wend WFouoXlG0  
        op.Type = "ShiftZ" PPEq6}  
        op.val1 = taq-0.01 jz*0`9&_  
        op.parent = parID BU`ckK\(  
        AddOperation eID, op xcst<=  
    * -0>3  
        Print "Set pupil diameter = " & pupilDiam KYp[Gs  
    yq?]V7~  
        'Update AZ Eye subassembly Description z) :ka"e  
        eID = FindFullName( "Geometry.Arizona Eye" ) IroPx#s:i  
        GetEntity eID, entity c S4DN  
        entity.Description = "Accommodation = " & A & "D" yO00I`5  
        SetEntity eID, entity g0PT8]8  
    !NTH.U:g  
        Update 'r\ 4}Ik  
        Print "DONE!" =~&VdPZ  
         %)?`{O~ h  
    End Sub w8p8 ;@  
    H(b)aw^(%  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: #.H}r6jqs  
    |#k@U6`SG  
    Accommodation = 4 Diopters zEj#arSE4  
    Pupil Diameter = 4 mm M%I@<~wl  
    Set aqueous humor thickness = 2.81 [KSH~:h:NR  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 nBkh:5E5%  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 A (okv  
    Set lens thickness = 3.927 -}P7$|O &  
    Set lens index of refraction = 1.42672 _|A+ ) K  
    Set pupil diameter = 4 a7#?h%wf  
    DONE! 5pfYEofK[  
     
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