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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 }^R_8{>k  
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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。 5};$>47m  
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    模型 t@O4 !mFH  
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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。 Ud8*yB  
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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. Y?>us  
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    光源 Vt!<.8&`  
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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。 MlM2(/ok  
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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。 BLvI[b|3gn  
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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。  j{;RuNt  
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    图2. 字母F光源的设定方法光 Iu -CXc  
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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 U8 b1 sz  
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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。 Kx;DmwX-  
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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。 Bw[jrK  
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    图5. 视网膜重点采样规格设定
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    脚本 zTa>MzH1-;  
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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: PZdYkbj  
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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。 Bn"r;pqWiT  
    余下的脚本计算与屈光度有关的所有参数。 WLAJqmC]  
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    分析 Rro{A+[,X  
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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。 D k'EKT-  
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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 =oF6|\]{ ;  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. rI:KZ}GZ  
    1 ]@}+H  
    Dim entity As T_ENTITY RTSR-<{z  
    Dim op As T_OPERATION Or9@X=C  
    Dim mat As T_MODELMATERIAL ^/W 7Xd(s  
    Dim A As Double {I |k@  
    Dim pupilDiam As Double K;f'&9-+i,  
    Dim eID As Long 4M8AYh2)  
    Dim parID As Long r<oI4px  
    Dim count As Integer k"SmbFn%N0  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double \ooqa<_  
    Dim tlens As Double, nlens As Double z#!xqIg0  
    Dim curv As Double, conic As Double xae rMr  
    Dim ok As Long NEO~|B*oDU  
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    Sub Main ,h2q 37  
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        '用户输入对话框 @"s\eL,r  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1  hh"0z]  
            TextBox 220,21,40,21,.TextBox1 'default: 0 JXeqVKF  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 @2_s;!K  
            OKButton 40,91,90,21 co3H=#2a  
            CancelButton 190,91,90,21 x 0  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 kXC.rgal  
            TextBox 220,49,40,21,.TextBox2 'default: 4 ^c]Sl  
        End Dialog .;tO;j |6  
        Dim dlg As UserDialog yT&bS\  
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        ok = Dialog (dlg) hkgPC-  
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        If ok=0 Then    'cancel button was pressed 2al~`  
            Print "Execution cancelled." 3i(k6)H$4  
            End ~~1~_0?e  
        End If *vhm  
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        'Assign accommodation and pupil diameter & use defaults if field left empty U>;itHW/  
        If dlg.TextBox1 = "" Then b=T+#Jb  
            A = 0           'Default accommodation %FFw!eVi  
        Else H>XbqIkL@  
            A = CDbl(dlg.TextBox1) YLd 5  
        End If N0RFPEQ~  
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        If dlg.TextBox2 = "" Then na']{a 1K  
            pupilDiam = 4   'Default pupil diameter z%/ww7H  
        Else &`L5UX  
            pupilDiam = CDbl(dlg.TextBox2) \N#)e1.0P  
        End If e+R.0E  
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        Print " " <Awx:lw.  
        Print "Accommodation = " & A & " Diopters" ($(1KE  
        Print "Pupil Diameter = " & pupilDiam & " mm" \>=YxB q  
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        ' Calculate new parameters with accommodation J|FyY)_  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness cHsJQU*K6  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens oZCi_g 5i  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens JNp`@`0V  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens T4!]^_t^  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens x>8f#B\Mr  
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        tlens = 3.767 + 0.04*A                  'Lens thickness hTG d Uw]  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 3sZK[Y|ax  
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        'Adjust parameters to account for accommodation UdI>x 4bI  
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        '************************************************************************* @J<B^_+Se  
        'Aqueous thickness (Position of Lens) Na~_=3+a  
        '************************************************************************* &HXSO,@  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) fd,~Yj$R?  
        GetCustomElement eID, entity g?$9~/h :;  
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        parID = FindFullName( "Geometry.Arizona Eye" ) x b0+4w|  
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        ' Delete any shift(s) in z %xZ.+Ff%  
        count = 0 {H+?DMh  
        While GetOperationCount(eID)>count fcZOsTj  
            GetOperation eID, count, op f<;9q?0VF  
            If op.Type="ShiftZ" Then `2fuV]FW  
                DeleteOperation eID,count blN1Q%m6  
                count=count-1 ppnj.tLz;r  
            End If %@&)t?/=  
            count=count+1 O(~Vvoq  
        Wend _(z"l"l=$  
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        'Set new shift in =5|5j!i=q  
        op.Type = "ShiftZ" 5?fk;Q9+\  
        op.val1 = taq V]O :;(W_  
        op.parent = parID h@DJ/&;u@  
        AddOperation eID, op 2>!ykUw^O  
        Print "Set aqueous humor thickness = " & taq-0.55 .)3 2WD%  
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        '************************************************************************* >gSerDH8\  
        'Radius and conic constant of anterior lens 8 KkpXaz  
        '************************************************************************* "QF083$  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) }6bLukv  
        GetConic eID, entity, curv, conic I>5@s;  
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        SetConic eID, entity, 1/Rant, CCant Zb }PP;O  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant c'B"Onu@m*  
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        '************************************************************************* _5T7A><q<  
        'Radius and conic constant of posterior lens +Y~+o-_  
        '************************************************************************* *e6|SZ &3  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) @(cS8%wK  
        GetConic eID, entity, curv, conic yx2.7h3  
    '/H(,TM  
        SetConic eID, entity, 1/Rpost, CCpost Y2X1!Em>B  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 9^ r  
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        '************************************************************************* YP<]f>SBt  
        'Lens thickness (Position of posterior lens surface) +I<Sq_-  
        '************************************************************************* ]K7  64}  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) #& wgsGV8C  
    OkZ!ZS h  
        ' Delete any z-shift(s) Y*k<NeDyn  
        count = 0 OQ7c| O  
        While GetOperationCount(eID)>count uB1!*S1f  
            GetOperation eID, count, op !7)ID7d  
            If op.Type="ShiftZ" Then ^I{]Um:  
                DeleteOperation eID,count "Cc"y* P  
                count=count-1 3- bcY4  
            End If [bv@qBL  
            count=count+1 *?D2gaCta  
        Wend l,u{:JC  
    =BS'oBn^6  
        'Set new z-shift <S$21NtM87  
        op.Type = "ShiftZ" winJ@IYW  
        op.val1 = tlens zt2-w/[Q  
        op.parent = parID n ;5?^Un%  
        AddOperation eID, op DH9?2)aR  
        Print "Set lens thickness = " & tlens !|h2&tH  
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        '************************************************************************* xD# I&.  
        'Lens index of refraction f*vk1dS:*3  
        '************************************************************************* G=cH61  
        eID = FindMaterial( "Lens" ) %GbPrlu  
        GetModelMaterial eID, mat K=x1m M+RK  
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        mat.Nd = nlens rp#*uV9;  
        SetModelMaterial eID, mat }AW)R&m  
        Print "Set lens index of refraction = " & nlens &PuJV +y  
    R6Mxdm2P}  
        '************************************************************************* 1vs>2` DLa  
        'Pupil diameter aRKRy  
        '************************************************************************* j!MA]0lTM  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) !7`=rT&  
    S1juAV=  
        'Adjust pupil diameter (trimming volume inner hole) b*F~%K^i$  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" UT<b v}(J  
    q>(u>z!  
        ' Adjust pupil location to just in front of the lens {2k< k(,  
        parID = FindFullName( "Geometry.Arizona Eye" ) %4|}&,%%r  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) V 1nZ M  
        count = 0 (vsk^3R[6  
        While GetOperationCount(eID)>count gpK_0?%  
            GetOperation eID, count, op u AS8F=9xP  
            If op.Type="ShiftZ" Then dU>R<jl!$  
                DeleteOperation eID,count J s<MJ4r>/  
                count=count-1 uU(G_E ?  
            End If +.#S[G  
            count=count+1 *DC Nu{6  
        Wend 3b)T}g  
        op.Type = "ShiftZ" uM)9b*Vbo  
        op.val1 = taq-0.01 5'c+313 lm  
        op.parent = parID 199hQxib:  
        AddOperation eID, op |@L &yg,x  
    <fsn2[V:B%  
        Print "Set pupil diameter = " & pupilDiam Be>c)90bO_  
    *CY6 a  
        'Update AZ Eye subassembly Description 0SCW2/o8  
        eID = FindFullName( "Geometry.Arizona Eye" ) 2PP-0 E  
        GetEntity eID, entity }Q r0T  
        entity.Description = "Accommodation = " & A & "D" wy_;+ 'Y  
        SetEntity eID, entity ?sf2h:\N  
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        Update <x0uO  
        Print "DONE!" h/0-Mrk;e  
         S,Wl)\  
    End Sub [+MH[1Vr={  
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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: gvc' $9%  
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    Accommodation = 4 Diopters n?e@):  
    Pupil Diameter = 4 mm ~?`9i>3W~  
    Set aqueous humor thickness = 2.81 Q$.V:#  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 5lHN8k=mm2  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 llaZP(pJ  
    Set lens thickness = 3.927 AY/-j$5+?  
    Set lens index of refraction = 1.42672 Ro'4/{}+  
    Set pupil diameter = 4 i5E:FS^!I  
    DONE! Tu= eQS|'  
     
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