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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 s%p,cz; ,  
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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。 Y9_OkcW)  
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    模型 !3 j@gi2  
    >y7|@'V[v0  
    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。 vh">Z4  
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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. byB ESyV!O  
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    光源 O2 sAt3'  
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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。 X!/o7<  
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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。 k),!%6\(  
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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。 pk5W!K  
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    图2. 字母F光源的设定方法光  XBF]|}%  
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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 T~" T%r  
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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。 _J+p[=[L  
    IS9}@5`'  
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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。 M^twD*  
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    图5. 视网膜重点采样规格设定
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    脚本 L@t}UC  
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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: ds9L4zfO  
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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。 M*x1{g C/  
    余下的脚本计算与屈光度有关的所有参数。  {Hp*BE   
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    分析 d l<7jM?  
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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。 w?LDaSz\t  
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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 LQs>[3rK  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. OB{d^e}  
    ?z]h Ysy  
    Dim entity As T_ENTITY kUp[b~  
    Dim op As T_OPERATION rnV\O L  
    Dim mat As T_MODELMATERIAL ;[ag|YU$Y  
    Dim A As Double v|r=}`k=  
    Dim pupilDiam As Double wgeR%#DW  
    Dim eID As Long n M?mdb  
    Dim parID As Long }%;o#!<N(@  
    Dim count As Integer tAM t7p-  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ",hPy[k  
    Dim tlens As Double, nlens As Double Qq.ht  
    Dim curv As Double, conic As Double !N@d51T=N  
    Dim ok As Long 9O.okU  
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    Sub Main e/p2| 4;  
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        '用户输入对话框 ^=lh|C\#  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 A=z+@b6  
            TextBox 220,21,40,21,.TextBox1 'default: 0 `~hB-Z5dI  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 N`JkEd7TT  
            OKButton 40,91,90,21 >4.K>U?0FC  
            CancelButton 190,91,90,21 ~_ 8X%ut y  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ?C[W~m P  
            TextBox 220,49,40,21,.TextBox2 'default: 4 #9a\Ab  
        End Dialog H:d@@/  
        Dim dlg As UserDialog 8?> #  
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        ok = Dialog (dlg) *&d>Vk."]  
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        If ok=0 Then    'cancel button was pressed 4zRz U  
            Print "Execution cancelled." ~'[0-_]=f  
            End xxsax/h  
        End If ds*N1[ *  
    #'@pL0dj  
        'Assign accommodation and pupil diameter & use defaults if field left empty t Lz,t&h  
        If dlg.TextBox1 = "" Then sr=~U q{g  
            A = 0           'Default accommodation <;R}dlBASW  
        Else :?*|Dp1  
            A = CDbl(dlg.TextBox1) ;_HG 5}i  
        End If =Z3{6y}3p  
    ~ry B*eZH  
        If dlg.TextBox2 = "" Then 4DYa~ =w  
            pupilDiam = 4   'Default pupil diameter R0l5"l*@+  
        Else 'nrX RDb  
            pupilDiam = CDbl(dlg.TextBox2) $mV1K)ege  
        End If -8r';zR  
    .}wVM`81z  
        Print " "  MYD`P2F  
        Print "Accommodation = " & A & " Diopters" CTG:C5OK  
        Print "Pupil Diameter = " & pupilDiam & " mm" DxFmsjX[L  
    e#+u8LrN  
        ' Calculate new parameters with accommodation 8R) 0|v&;  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Ly7|:IbC  
    W7_j;7'  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens co93}A,k  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens CWTPf1?eB  
    /f5*KRM  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens &$1ifG   
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens . paA0j  
    rF3QmR?l  
        tlens = 3.767 + 0.04*A                  'Lens thickness  rk F>c  
    YT*_ vmJV  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 5Hli@:B2s  
    ]f3[I3;K  
        'Adjust parameters to account for accommodation R 2{kS  
    va>u1S<lO  
        '************************************************************************* X\ -IAv  
        'Aqueous thickness (Position of Lens) O3YD jas  
        '************************************************************************* Ap :mc:  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) - kGwbV}  
        GetCustomElement eID, entity MsaD@JY.y  
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        parID = FindFullName( "Geometry.Arizona Eye" ) lR[]A  
    /#lqv)s'  
        ' Delete any shift(s) in z 0:CIM  
        count = 0 u%o]r9xl'  
        While GetOperationCount(eID)>count DFk0"+Ky  
            GetOperation eID, count, op lBpy0lo#  
            If op.Type="ShiftZ" Then TbUouoc  
                DeleteOperation eID,count u{6b>c|,X  
                count=count-1 y:m ;_U,%c  
            End If u . xUM  
            count=count+1 !a.|URa7  
        Wend :aIS>6  
    hR g?H  
        'Set new shift in V!{}%;f  
        op.Type = "ShiftZ" Sj[iKCEKtv  
        op.val1 = taq i7%v2_  
        op.parent = parID ~$WBcqo  
        AddOperation eID, op /.1yxb#Z?,  
        Print "Set aqueous humor thickness = " & taq-0.55 @L9C_a  
    )w t mc4'  
        '************************************************************************* HGwSsoS  
        'Radius and conic constant of anterior lens YQH=]5r  
        '************************************************************************* } xy>uT  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ,:E*Mw:  
        GetConic eID, entity, curv, conic <Lt%[dn  
    /O^aFIxk  
        SetConic eID, entity, 1/Rant, CCant uZg[PS=@!X  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant dr[sSBTY"  
    Fx3CY W  
        '************************************************************************* $ #*";b)QY  
        'Radius and conic constant of posterior lens ~YH'&L.O  
        '************************************************************************* YLx4qE  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) o4zX 41W  
        GetConic eID, entity, curv, conic 1@i|[dq  
    6H#4iMeh  
        SetConic eID, entity, 1/Rpost, CCpost ~ \{a<-R  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost fK0VFN8<I  
    }%T8?d]  
        '************************************************************************* ]SO-NR  
        'Lens thickness (Position of posterior lens surface) '1 }ybSG  
        '************************************************************************* X%Lhu6F  
    z>6hK:27  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) <27:O,I  
    kA"|PtrW  
        ' Delete any z-shift(s) lB(E:{6OZ  
        count = 0 Qvx[F:#Tk  
        While GetOperationCount(eID)>count -5 Q gJ  
            GetOperation eID, count, op fHLt{!O  
            If op.Type="ShiftZ" Then AW R   
                DeleteOperation eID,count l9P=1TL  
                count=count-1 4#D<#!]^  
            End If sU=7)*$  
            count=count+1 DD?zbN0X  
        Wend k$ORVU  
    rP7[{'%r  
        'Set new z-shift Od,P,t9  
        op.Type = "ShiftZ" 5fT"`FL?  
        op.val1 = tlens "8-;Dq'+  
        op.parent = parID '|7'dlW  
        AddOperation eID, op u^ 3,~:E  
        Print "Set lens thickness = " & tlens :f/T $fa*  
    \Qgc7ev  
        '************************************************************************* y"L7.B  
        'Lens index of refraction o?O> pK  
        '************************************************************************* WSKubn?7B  
        eID = FindMaterial( "Lens" ) (>R   
        GetModelMaterial eID, mat B*3<(eI  
    qj #C8Tc7  
        mat.Nd = nlens i[#XYX'\  
        SetModelMaterial eID, mat ;S5J"1)O~  
        Print "Set lens index of refraction = " & nlens XZ&cTjNB&  
    "8#EA<lsS  
        '************************************************************************* Ifu[L&U  
        'Pupil diameter DmA~Vj!a^y  
        '*************************************************************************  T1\@4x  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ~85>.o2RDW  
    w~%Rxdh?8W  
        'Adjust pupil diameter (trimming volume inner hole) Ds<~JfVl  
    QSNPraT  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" w2(pgWed  
    1Uaj}= @M  
        ' Adjust pupil location to just in front of the lens J P1XH k  
        parID = FindFullName( "Geometry.Arizona Eye" ) xo.k:F  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) [a[.tR38e  
        count = 0 ?lPyapA]  
        While GetOperationCount(eID)>count B'D\l\w  
            GetOperation eID, count, op _wp_y-"  
            If op.Type="ShiftZ" Then B4M rrW4=  
                DeleteOperation eID,count U^&,xz$Cg  
                count=count-1 7@NV|Idtd  
            End If '5r\o8RjN  
            count=count+1 M?ObK#l!_  
        Wend ]I[\Io1  
        op.Type = "ShiftZ" QnTKo&|9  
        op.val1 = taq-0.01 N!~5S`  
        op.parent = parID kc7,F2=F  
        AddOperation eID, op L']"I^( N  
    xh:A*ZI=7  
        Print "Set pupil diameter = " & pupilDiam [lz#+~rOS  
    Wi+}qO  
        'Update AZ Eye subassembly Description PY76;D*`  
        eID = FindFullName( "Geometry.Arizona Eye" ) WXs?2S*  
        GetEntity eID, entity m|]:oT`M  
        entity.Description = "Accommodation = " & A & "D" <5]ufv  
        SetEntity eID, entity EpU}~vC9C  
    H{et2J<H  
        Update k4-S:kVo  
        Print "DONE!" ( &!RX.i  
         $e, N5/O  
    End Sub I&wJK'GM`  
     &Sdf0"  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: H#/Hs#  
    =oT4!OUf  
    Accommodation = 4 Diopters qORL 7?{  
    Pupil Diameter = 4 mm WYm<_1  
    Set aqueous humor thickness = 2.81 \OW.?1d  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 H{4_,2h =m  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 ;Xl {m`E+  
    Set lens thickness = 3.927 }Y!v"DO#Q*  
    Set lens index of refraction = 1.42672 }B ?_>0  
    Set pupil diameter = 4 I|<`Er-;58  
    DONE! PS3jCT  
     
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