[技术]Arizona眼睛模型 [复制链接]

简介 >J>|+W  
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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。 |?Bb{Es  
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模型 l5fF.A7TT  
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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。 n9N'}z  
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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.
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光源 6kM'f}t[C  
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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。 2i_X{!0}  
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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。 {_<,5)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。 r]'Q5l4j6"  
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视网膜的散射 2*1FW v  
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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。 KXTx{R  
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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。 J~URv)g  
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脚本  e+=IGYC  
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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： zA?]AL(+YW  
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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。 8NS1*\z  
余下的脚本计算与屈光度有关的所有参数。 NDaM;`  
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分析 aA/.EAc7  
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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。 YDMimis\H5  
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脚本代码 <DjFMTCN  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. :$"L;"  
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Dim entity As T_ENTITY zrJ/Fs+s  
Dim op As T_OPERATION z}[qk:  
Dim mat As T_MODELMATERIAL umo@JWr  
Dim A As Double wWNHZv&  
Dim pupilDiam As Double H!NyM}jsr  
Dim eID As Long Xu8_
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Dim parID As Long 8Qg,UX  
Dim count As Integer c#6g[TE@  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double g@jAIy]  
Dim tlens As Double, nlens As Double B "z`X!\  
Dim curv As Double, conic As Double L)LW5%.6  
Dim ok As Long *4tJ|m6"Y6  
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Sub Main  `=h`:`  
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    '用户输入对话框 NHCdf*  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 -^sbf.  
        TextBox 220,21,40,21,.TextBox1 'default: 0 =tv,B3Mo  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Pkbx/\  
        OKButton 40,91,90,21 8,,$C7"EP  
        CancelButton 190,91,90,21 8C{mV^cn~  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 DGwN*>X  
        TextBox 220,49,40,21,.TextBox2 'default: 4 z$>_c"D  
    End Dialog x{X(Y]*1S  
    Dim dlg As UserDialog &l=%*`On  
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    ok = Dialog (dlg) 9p#Laei].  
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    If ok=0 Then    'cancel button was pressed AIvIQ$6}  
        Print "Execution cancelled." K;u<-?En  
        End {5=Iu\
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    End If bJo)rM:m  
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    'Assign accommodation and pupil diameter & use defaults if field left empty bnz2\C9^  
    If dlg.TextBox1 = "" Then G' ~Z'  
        A = 0           'Default accommodation D9;2w7v  
    Else &_^t
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        A = CDbl(dlg.TextBox1) >h0iq  
    End If cVt MCgx  
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    If dlg.TextBox2 = "" Then &;%z1b>F  
        pupilDiam = 4   'Default pupil diameter 1N_G
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    Else swBgV,;  
        pupilDiam = CDbl(dlg.TextBox2) Nd.+Rs  
    End If
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    Print " " kgX"LQh;[G  
    Print "Accommodation = " & A & " Diopters" +P?!yH,n  
    Print "Pupil Diameter = " & pupilDiam & " mm" (3DjFT3 w  
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    ' Calculate new parameters with accommodation Gk9Y{  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ^T[8j/9o^  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens
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    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens R#ABda9  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens (5s$vcK  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 0^41dfdE  
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    tlens = 3.767 + 0.04*A                  'Lens thickness lLO|,  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction [*<F   
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    'Adjust parameters to account for accommodation }Km+5'G'U  
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    '************************************************************************* uT'}_2=:  
    'Aqueous thickness (Position of Lens) g-0?8q5T6  
    '*************************************************************************
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    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ^t&S?_DSZ  
    GetCustomElement eID, entity CbmT aEaP  
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    parID = FindFullName( "Geometry.Arizona Eye" ) )[d?&GK  
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    ' Delete any shift(s) in z ,m| :U  
    count = 0 ~c&ygL3  
    While GetOperationCount(eID)>count si:p98[w  
        GetOperation eID, count, op "HCJ!  
        If op.Type="ShiftZ" Then >wz&{9ni  
            DeleteOperation eID,count tC0:w,C)  
            count=count-1
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        End If LU
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        count=count+1 Zl5cHejM  
    Wend I}djDtJ  
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    'Set new shift in k8!|WqfP  
    op.Type = "ShiftZ" b&AGVW
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    op.val1 = taq !~+"TI}_%w  
    op.parent = parID pFfd6P  
    AddOperation eID, op {E6M_qZ  
    Print "Set aqueous humor thickness = " & taq-0.55 @>Y.s6a  
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    '************************************************************************* 4e6x1`Y{xB  
    'Radius and conic constant of anterior lens td*1  
    '************************************************************************* J!O{.
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    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) C|#GODA  
    GetConic eID, entity, curv, conic Y>Oh]?  
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    SetConic eID, entity, 1/Rant, CCant N03)G2  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant b@G
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    '************************************************************************* 97/"5i9  
    'Radius and conic constant of posterior lens }HO3D.HE^  
    '************************************************************************* _[D6WY+  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) (v<l9}!  
    GetConic eID, entity, curv, conic 6n[O8^  
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    SetConic eID, entity, 1/Rpost, CCpost !*[Fw1-J  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost }BTK+Tk8  
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    '************************************************************************* F8u;C:^d  
    'Lens thickness (Position of posterior lens surface) ['<Q402:.  
    '************************************************************************* up(6/-/
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) h(M_ K  
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    ' Delete any z-shift(s) ORVFp]gG  
    count = 0 R,]J~TfPK  
    While GetOperationCount(eID)>count Y[_{tS#u  
        GetOperation eID, count, op <+7]EwVcn^  
        If op.Type="ShiftZ" Then T;7=05k<_  
            DeleteOperation eID,count DC9\Sp?  
            count=count-1 |p4D!M+$7  
        End If vy:-a G  
        count=count+1 JQi+y;  
    Wend ??\1eo2gB  
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    'Set new z-shift *$%ch=  
    op.Type = "ShiftZ" xIOYwVC  
    op.val1 = tlens w'[^RZW:j  
    op.parent = parID 9'$\G
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    AddOperation eID, op @u@N&{b5"  
    Print "Set lens thickness = " & tlens tu4-##{  
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    '************************************************************************* SRU}-  
    'Lens index of refraction ID{62>R  
    '************************************************************************* P\jnht  
    eID = FindMaterial( "Lens" ) )Y@E5Tuk>  
    GetModelMaterial eID, mat D8OW|wVE  
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    mat.Nd = nlens &ikPa,A  
    SetModelMaterial eID, mat xbVvK+  
    Print "Set lens index of refraction = " & nlens 9Dat oi  
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    '************************************************************************* vkR,Sn  
    'Pupil diameter `, lnBP3D"  
    '************************************************************************* 5`_UIYcI  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) oouhP1py,  
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    'Adjust pupil diameter (trimming volume inner hole)
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" f9%M:cl  
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    ' Adjust pupil location to just in front of the lens
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    parID = FindFullName( "Geometry.Arizona Eye" ) j1Ns|oph1  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) +hIC N,8!  
    count = 0 vtByCu5  
    While GetOperationCount(eID)>count 3rxB]-  
        GetOperation eID, count, op e(z'uA{!  
        If op.Type="ShiftZ" Then 8|cQW-L  
            DeleteOperation eID,count nB|m!fi<  
            count=count-1 T^
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        End If r_"=DLx6  
        count=count+1 > w-fsL  
    Wend oCxh[U@*D  
    op.Type = "ShiftZ" <MQTOz oj  
    op.val1 = taq-0.01 >D\jyd$wh&  
    op.parent = parID .or1*-B K  
    AddOperation eID, op (kYwD  
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    Print "Set pupil diameter = " & pupilDiam <rKfL`8p  
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    'Update AZ Eye subassembly Description .UGbo.e  
    eID = FindFullName( "Geometry.Arizona Eye" ) ML!>tCT  
    GetEntity eID, entity af>^<q  
    entity.Description = "Accommodation = " & A & "D" lZ*V.-D^
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    SetEntity eID, entity 2lu AF2  
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    Update x:? EL)(  
    Print "DONE!" 8[B0[2O  
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End Sub d#U~
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如果屈光度是4，光瞳直径是4，则会输出如下数据： W#bOx0  
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Accommodation = 4 Diopters NI^jQS M]  
Pupil Diameter = 4 mm oc>N| ww:  
Set aqueous humor thickness = 2.81 6JB*brO  
Set anterior lens radius = 10.4 and conic constant = -2.375869 r.ib"W#4  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 '}, 8x?  
Set lens thickness = 3.927 !+)5?o  
Set lens index of refraction = 1.42672 @R
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Set pupil diameter = 4 /J5)_>
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DONE! =JGL~t?