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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 e<gx~N9l'  
    f3WSa&eF  
    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。 u@FsLHn  
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    模型 EEf ]u7  
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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。 Sav`%0q?7a  
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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. Zzd/K^gg  
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    光源 3/M.0}e  
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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。 :h";c"  
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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。 e-D4'lu  
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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。 Na!za'qk[o  
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    图2. 字母F光源的设定方法光 @Hr+/52B  
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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 WBppKj_M  
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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。 m=&j@  
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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。 [wcA.g*F  
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    图5. 视网膜重点采样规格设定
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    脚本 {tzxA_  
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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: <]#o*_aFP  
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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。 I5pp "*u  
    余下的脚本计算与屈光度有关的所有参数。 P%GkcV  
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    分析 zv%J=N$G  
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 J@bW^>g*6u  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 _.f@Y`4d  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. Hhf72IX  
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    Dim entity As T_ENTITY OJ[rj`wrW^  
    Dim op As T_OPERATION dM|g`rr E  
    Dim mat As T_MODELMATERIAL :`<psvd  
    Dim A As Double F X 1C e  
    Dim pupilDiam As Double  <qn,  
    Dim eID As Long mmN|F$;r  
    Dim parID As Long tP]q4i  
    Dim count As Integer |a(Q4 e/,  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 4[l^0  
    Dim tlens As Double, nlens As Double |e"/Mf[  
    Dim curv As Double, conic As Double !"(u_dFw  
    Dim ok As Long DNho%Xk  
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    Sub Main J8h7e}n?  
    1#!@["  
        '用户输入对话框 *SGlqR['\e  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 >x?2Fz.  
            TextBox 220,21,40,21,.TextBox1 'default: 0 {h^c  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 BQU/QoDY  
            OKButton 40,91,90,21 j1Fw U  
            CancelButton 190,91,90,21 fIEw(k<*  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 {*__B} ,N  
            TextBox 220,49,40,21,.TextBox2 'default: 4 T/7vM6u  
        End Dialog 3jg'1^c  
        Dim dlg As UserDialog x)\V lR  
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        ok = Dialog (dlg) 4f jC  
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        If ok=0 Then    'cancel button was pressed w7ZG oh(  
            Print "Execution cancelled." zkG>u,B}  
            End ??+:vai2  
        End If 5l&jPk!=  
    [edH%S}\  
        'Assign accommodation and pupil diameter & use defaults if field left empty #'g^Za  
        If dlg.TextBox1 = "" Then Z*h ;e;  
            A = 0           'Default accommodation .S6ji~;r  
        Else #jgqkMOd,j  
            A = CDbl(dlg.TextBox1) -XLo0  
        End If -4%]QS  
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        If dlg.TextBox2 = "" Then DOT=U _  
            pupilDiam = 4   'Default pupil diameter v<+4BjV!J}  
        Else :r^klJ(m  
            pupilDiam = CDbl(dlg.TextBox2) ?to1rFrU  
        End If ;fkSrdj  
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        Print " " # hZQ>zcF  
        Print "Accommodation = " & A & " Diopters" .5^a;`-+  
        Print "Pupil Diameter = " & pupilDiam & " mm" 3~:0?Zuq  
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        ' Calculate new parameters with accommodation QK'`=MU  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness kLq( !Gs  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens >KKeV(Ur  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens v*vn<nPAQ>  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens tw-fAMwU  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Ia'x]#~  
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        tlens = 3.767 + 0.04*A                  'Lens thickness k=ts&9\  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction =hPG_4#  
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        'Adjust parameters to account for accommodation "I@v&(Am;  
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        '************************************************************************* RA} U#D:$i  
        'Aqueous thickness (Position of Lens) NWb} OXK/  
        '************************************************************************* Y+5"uq<'  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ZWFG?8lJ  
        GetCustomElement eID, entity f.J 9) lfb  
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        parID = FindFullName( "Geometry.Arizona Eye" ) })KJ60B  
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        ' Delete any shift(s) in z ,%[LwmET  
        count = 0 ) b/n)%6  
        While GetOperationCount(eID)>count mF}c-  D  
            GetOperation eID, count, op Z@}sCZ=#A  
            If op.Type="ShiftZ" Then 6NzBpur 2H  
                DeleteOperation eID,count 'YBi5_  
                count=count-1 3IGCl w(  
            End If (=`Z0)=  
            count=count+1 Z(KmS (  
        Wend c%ZeX%p  
    phr2X*Z/)Y  
        'Set new shift in IF5sqv  
        op.Type = "ShiftZ" Ap% d<\,Z  
        op.val1 = taq Hw\([j*  
        op.parent = parID <{E;s)hD?  
        AddOperation eID, op Q! Kn|mnN  
        Print "Set aqueous humor thickness = " & taq-0.55 ax4*xxU  
    U@#?T  
        '************************************************************************* xLe =d|6  
        'Radius and conic constant of anterior lens |3S'8Oe CI  
        '************************************************************************* ZH_FA  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) "\4]X"3<+  
        GetConic eID, entity, curv, conic ~B<97x(X  
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        SetConic eID, entity, 1/Rant, CCant kxygf9I!;  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant V_Xy2<V  
    nDyvX1]  
        '************************************************************************* >vHH  
        'Radius and conic constant of posterior lens T_uNF8Bh  
        '************************************************************************* zpbcmQB*  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ]}p2Tp;1  
        GetConic eID, entity, curv, conic ^I@ey*$  
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        SetConic eID, entity, 1/Rpost, CCpost ,c@r` x  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost _t$lcOT  
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        '************************************************************************* 1a5?)D  
        'Lens thickness (Position of posterior lens surface) 03~+-h& n  
        '************************************************************************* Ok*VQKyDLH  
    'uPxEu4 >4  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) /z/hUa  
    A * a{  
        ' Delete any z-shift(s) Km[]^;6  
        count = 0 ? UxG/]",  
        While GetOperationCount(eID)>count GEhdk]<a7  
            GetOperation eID, count, op \H,V 9!B  
            If op.Type="ShiftZ" Then ^?E^']H)5u  
                DeleteOperation eID,count _2]e1_=  
                count=count-1 g!p+rq_f  
            End If c zZrP"  
            count=count+1 <+<)xwOQ ]  
        Wend 2ZU@>W  
    ?+bTPl;%'  
        'Set new z-shift & 6`  
        op.Type = "ShiftZ" $/4Wod*l  
        op.val1 = tlens mw:3q6  
        op.parent = parID v>JB rIb$  
        AddOperation eID, op uOyLC<I/  
        Print "Set lens thickness = " & tlens )EhTM-1  
    HT{F$27W  
        '************************************************************************* ' %bj9{(0  
        'Lens index of refraction d 8xk&za  
        '************************************************************************* UeMnc 5y  
        eID = FindMaterial( "Lens" ) F(T=WR].o  
        GetModelMaterial eID, mat 9c"0~7v  
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        mat.Nd = nlens F?}m8ZRv  
        SetModelMaterial eID, mat d [\>'>  
        Print "Set lens index of refraction = " & nlens B$K7L'e+-  
    38"8,k  
        '************************************************************************* @).WIs  
        'Pupil diameter o@qN#Mg?>}  
        '************************************************************************* ] +}:VaeA  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ],BJ}~v,X  
    #gxRTx  
        'Adjust pupil diameter (trimming volume inner hole) o%kSR ]V|  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" _DNkdS [[  
    W)6U6  
        ' Adjust pupil location to just in front of the lens [{6&.v  
        parID = FindFullName( "Geometry.Arizona Eye" ) PiIp<fJd$  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) b|X>3(  
        count = 0 d_4n0Kh0  
        While GetOperationCount(eID)>count t:?<0yfp&  
            GetOperation eID, count, op 9`LU=Xv/  
            If op.Type="ShiftZ" Then 8r7/IGFg  
                DeleteOperation eID,count f9h:"Dnzin  
                count=count-1 8.Pcr<  
            End If {q5hF5!`)  
            count=count+1 Y;a6:>D%cT  
        Wend x]yHBc  
        op.Type = "ShiftZ" #J%h!#3g  
        op.val1 = taq-0.01 dg!1wD   
        op.parent = parID X+(aQ >y  
        AddOperation eID, op HB/ _O22  
    /u" cl2|  
        Print "Set pupil diameter = " & pupilDiam `^s]?  
    2:smt)f  
        'Update AZ Eye subassembly Description !Szgph"ul  
        eID = FindFullName( "Geometry.Arizona Eye" ) x9XGCr  
        GetEntity eID, entity ~Mg8C9B?%3  
        entity.Description = "Accommodation = " & A & "D" @B>%B EC  
        SetEntity eID, entity puf;"c6e'  
    = y,yQO  
        Update 4wM$5  
        Print "DONE!" [T$$od[.  
         dpc=yXg>"c  
    End Sub ?z4uze1  
    a$ +e8>  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: K'{wncumQ  
    1*c0\:BQ;z  
    Accommodation = 4 Diopters erAZG)  
    Pupil Diameter = 4 mm &9jUf:gJ0  
    Set aqueous humor thickness = 2.81 B?/12+sR  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 EF_h::A_  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 z- {"pI  
    Set lens thickness = 3.927 ?j^?@%f0  
    Set lens index of refraction = 1.42672 gZ79u  
    Set pupil diameter = 4 Og%zf1)aZM  
    DONE! n WO~v{h3J  
     
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