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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 b"Jr_24t3v  
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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。 .R^ R|<x  
    +`!>lo{X  
    模型 &#OF,_6"m  
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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。 $"va8,  
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    Table 1. AZ眼睛模型的定义
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    在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. #"C!-kS'=  
    +W8kMuM!  
    光源 g+Y &rz  
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    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 )~IOsTjI  
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    图1. 光源和提示信息使用
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    除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 Ml/K~H tN  
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    在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 s+^1\  
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    图2. 字母F光源的设定方法光 %v UUx+  
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    图3. 字母F在视网膜上位置点列图
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    视网膜的散射 #TcX5  
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    在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 IR32O,)  
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    图4. 视网膜朗伯散射设定
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    注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 j"+6aD/lv  
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    图5. 视网膜重点采样规格设定
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    脚本 lB7/oa1]>  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: OaY]}4tI$  
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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。 21] K7  
    余下的脚本计算与屈光度有关的所有参数。 3f:]*U+O  
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    分析 9l,8:%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。 oWggh3eXk  
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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 [=:4^S|M  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. AP9\]qZ(7  
    U^-RyE!}  
    Dim entity As T_ENTITY )=5*iWe  
    Dim op As T_OPERATION }IQ![T5  
    Dim mat As T_MODELMATERIAL z_). -  
    Dim A As Double iztgk/(+G  
    Dim pupilDiam As Double )-1$y+s>  
    Dim eID As Long $U2Jq@G*  
    Dim parID As Long [P]M)vJ**  
    Dim count As Integer 5U*${  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 1+l[P9?R[  
    Dim tlens As Double, nlens As Double bHzZ4i  
    Dim curv As Double, conic As Double hJX;/~L  
    Dim ok As Long [TT:^F(Y  
    |r4&@)  
    Sub Main X*e:MRw[  
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        '用户输入对话框 N8!e(Y K_  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 #Zn+-Ih  
            TextBox 220,21,40,21,.TextBox1 'default: 0 F^!mgU X  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 p4K 8L'nZ  
            OKButton 40,91,90,21 Iapzhy2l  
            CancelButton 190,91,90,21 y;hco  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 (unJwh{7Q  
            TextBox 220,49,40,21,.TextBox2 'default: 4 HBw0 N?  
        End Dialog j>~ @vq  
        Dim dlg As UserDialog NNRKYdp,  
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        ok = Dialog (dlg) + Cq&~<B  
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        If ok=0 Then    'cancel button was pressed u7-0?  
            Print "Execution cancelled." UQtG<W]<  
            End /!y3ZzL  
        End If 1z3I^gI*i  
    NE Z ]%  
        'Assign accommodation and pupil diameter & use defaults if field left empty ]O~/k~f  
        If dlg.TextBox1 = "" Then 8)J,jh9q  
            A = 0           'Default accommodation >~&7D`O  
        Else p\xsW "=8q  
            A = CDbl(dlg.TextBox1) > !HC ?  
        End If *Oy%($'  
    \BSPv]d  
        If dlg.TextBox2 = "" Then dw7h@9\ y  
            pupilDiam = 4   'Default pupil diameter ` $[`C/h  
        Else o2LUB)=R'  
            pupilDiam = CDbl(dlg.TextBox2) $U%N$_k?  
        End If 2f 9%HX(5  
    RY*s}f  
        Print " " 3N{ ZX{}  
        Print "Accommodation = " & A & " Diopters" PmDar<m  
        Print "Pupil Diameter = " & pupilDiam & " mm" 1{wOjq(4  
    3<6P^p=I  
        ' Calculate new parameters with accommodation $7\hszjZ  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness }$s._)a  
    McU]U 9:z  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens |CjdmQ u  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens w"j[c#vM  
    om,=.,|Ld  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens {>#4{D00  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ;[-y>qU0  
    jyjK~ !0  
        tlens = 3.767 + 0.04*A                  'Lens thickness {7FD-Q[tS  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction =+wkjTO  
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        'Adjust parameters to account for accommodation QBT_H"[  
    @nF#\  
        '************************************************************************* N~ M-|^L  
        'Aqueous thickness (Position of Lens) L|w}#|-  
        '************************************************************************* O.P:~  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) K 7d]p0d'  
        GetCustomElement eID, entity <' b%  
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        parID = FindFullName( "Geometry.Arizona Eye" ) !rgdOlTR^  
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        ' Delete any shift(s) in z O7T wM Yh  
        count = 0 -"3<Ll  
        While GetOperationCount(eID)>count *AN2&>Y  
            GetOperation eID, count, op ^2um.`8  
            If op.Type="ShiftZ" Then 2<5s0GT'/  
                DeleteOperation eID,count !8>tT  
                count=count-1 `=~d^wKYJ3  
            End If WqRg/  
            count=count+1 Nv_"?er+y  
        Wend ,LJX  
    ||k^pzj%  
        'Set new shift in $+a2CZs!  
        op.Type = "ShiftZ" C$$lJ=>  
        op.val1 = taq !/MHD  
        op.parent = parID DvvjIYB~  
        AddOperation eID, op q9c:,k  
        Print "Set aqueous humor thickness = " & taq-0.55 KA$l.6&d  
    ]i@VIvYq  
        '************************************************************************* \)vxZ!  
        'Radius and conic constant of anterior lens lTpmoDa%  
        '************************************************************************* S[cVoV  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) *.0#cP7 "  
        GetConic eID, entity, curv, conic bPtbU :G  
    U GJ# "9  
        SetConic eID, entity, 1/Rant, CCant Y r^C+Oyg  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @[4Tdf  
    -kd_gbnr3  
        '************************************************************************* j*jO809%^  
        'Radius and conic constant of posterior lens 9*}?0J8  
        '************************************************************************* S_B;m1  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) CvtG  
        GetConic eID, entity, curv, conic Yj^n4G(h  
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        SetConic eID, entity, 1/Rpost, CCpost 9L'R;H?L  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost wA<#E6^vG  
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        '************************************************************************* 0UvN ws  
        'Lens thickness (Position of posterior lens surface) NPM}w!  
        '************************************************************************* ?5!>k^q  
    |PED8K:rU  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) %Ot^G%34  
    ')/yBH9mR  
        ' Delete any z-shift(s) IU`&h2KZ.  
        count = 0 V{[vIt*  
        While GetOperationCount(eID)>count lT3, G#(  
            GetOperation eID, count, op fK|F`F2V  
            If op.Type="ShiftZ" Then @iwg`j6ol  
                DeleteOperation eID,count f|1GlUA{t  
                count=count-1 S 5Q$dAL  
            End If tc@([XqH  
            count=count+1 T.zU erbO  
        Wend ` AA[k  
    t F<|Eja *  
        'Set new z-shift S&@uY#_(*T  
        op.Type = "ShiftZ" KS/1ux4x  
        op.val1 = tlens 6* /o  
        op.parent = parID DM%4 V|F"  
        AddOperation eID, op nkp!kqJ09  
        Print "Set lens thickness = " & tlens L+PrV y  
    )0P>o]fWI  
        '************************************************************************* i!30f^9D-S  
        'Lens index of refraction L s=2!  
        '************************************************************************* <=*xwI&q  
        eID = FindMaterial( "Lens" ) &z r..i4O  
        GetModelMaterial eID, mat c"3 a,&  
    *1}'ZEaJ  
        mat.Nd = nlens I"^ `!8<q  
        SetModelMaterial eID, mat {<a(1#{  
        Print "Set lens index of refraction = " & nlens b<B|p|  
    VGY#ph%  
        '************************************************************************* Y zXL8  
        'Pupil diameter N6Fj} m&E  
        '************************************************************************* aUN!Sd2,  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) J}qk:xGL  
    +1 H.5|  
        'Adjust pupil diameter (trimming volume inner hole) \ qc 8;"@  
    -So&?3,\A@  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" \w!G  
    `}KK@(Y  
        ' Adjust pupil location to just in front of the lens nl|}_~4U  
        parID = FindFullName( "Geometry.Arizona Eye" ) z6 v RTY  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) iO;q]  
        count = 0 XX5 ):1  
        While GetOperationCount(eID)>count N?H;fK4v  
            GetOperation eID, count, op h5G>FPM-=  
            If op.Type="ShiftZ" Then rHu  #  
                DeleteOperation eID,count iq '3.-xYr  
                count=count-1 `5;O|qRq  
            End If AAkdwo  
            count=count+1 zm}4=Kz}  
        Wend %Ysu613mz  
        op.Type = "ShiftZ" 2P8JLT*Tj  
        op.val1 = taq-0.01 $Xw .iN]g  
        op.parent = parID <D4.kM  
        AddOperation eID, op +d6/*}ht  
    AA9OElCa  
        Print "Set pupil diameter = " & pupilDiam `?PZvGi  
    .}6 YKKqS  
        'Update AZ Eye subassembly Description Rx*T7*xg{  
        eID = FindFullName( "Geometry.Arizona Eye" ) *Wv]DV=\  
        GetEntity eID, entity >De\2gbJ  
        entity.Description = "Accommodation = " & A & "D" o_p//S#q  
        SetEntity eID, entity e@s+]a8D-k  
    2>#Pt^R:C  
        Update 4^VY  
        Print "DONE!" |n3PznV  
         ,b=&iDc  
    End Sub BclZsU=xn  
    NjVuwIm+  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: %O;"Z`I  
    Zgo^M,g  
    Accommodation = 4 Diopters SC`.VCfc.  
    Pupil Diameter = 4 mm Dg/&m*Yl  
    Set aqueous humor thickness = 2.81 AZxx%6  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 0ANqEQX  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 `~[zIq:}7  
    Set lens thickness = 3.927 VcT(n7  
    Set lens index of refraction = 1.42672 H1f){L97wR  
    Set pupil diameter = 4 s,N%sO;  
    DONE! ;g: TsYwM  
     
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