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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 8@Zg@>,  
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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。 iV h^;  
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    模型 \8Mn[G9TL  
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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。 YCv)DW;  
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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. (G:A^z  
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    光源 }ll&qb  
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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。 Yt]tRqrh;T  
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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。 "gm[q."n<  
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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。 lSMv9 :N  
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    图2. 字母F光源的设定方法光 D{-h2=V  
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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 U3Fa.bC6}  
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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。 w_c)iJ  
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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。 *QKxrg  
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    图5. 视网膜重点采样规格设定
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    脚本 3.i$lp`t  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: A -C.Bi;/  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
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    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 #Hn<4g"AjM  
    余下的脚本计算与屈光度有关的所有参数。 RIhu9W   
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    分析 xq6 eu 9   
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 <z'Pj7c[  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 csh@C ckC8  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. =`MxgK +  
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    Dim entity As T_ENTITY :Dt]sE _d  
    Dim op As T_OPERATION oI\ Lepl*  
    Dim mat As T_MODELMATERIAL EZ,Tc ;f=  
    Dim A As Double CP]nk0  
    Dim pupilDiam As Double =3h?!$#?  
    Dim eID As Long 1K* `i(  
    Dim parID As Long Kw%to9 eh)  
    Dim count As Integer :d AC:h  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double F"-u8in`  
    Dim tlens As Double, nlens As Double :P2{^0$  
    Dim curv As Double, conic As Double f|v5i tO2  
    Dim ok As Long c-jE1y<  
    !W\za0p  
    Sub Main 539f B,  
    <<FBT`Y[  
        '用户输入对话框 Y>J$OA:  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 dguN<yS- E  
            TextBox 220,21,40,21,.TextBox1 'default: 0 0?$jC-@k:  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 mm dQ\\  
            OKButton 40,91,90,21 C vOH*K'  
            CancelButton 190,91,90,21 )%+7"7.  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 =(==aP  
            TextBox 220,49,40,21,.TextBox2 'default: 4 whW% c8  
        End Dialog #+"1">l  
        Dim dlg As UserDialog +L\Dh.Ir  
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        ok = Dialog (dlg) 1zcaI^e#  
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        If ok=0 Then    'cancel button was pressed e0"80"D  
            Print "Execution cancelled." 1!S*z^LGl  
            End h@2YQgw`  
        End If 9cIKi#Bl  
    ^XgBkC~  
        'Assign accommodation and pupil diameter & use defaults if field left empty 5y~ Srb?2  
        If dlg.TextBox1 = "" Then &cpqn2Z  
            A = 0           'Default accommodation CcJ%; .V,T  
        Else , 3&D A  
            A = CDbl(dlg.TextBox1) p 2>\  
        End If TWeup6k  
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        If dlg.TextBox2 = "" Then V[;^{,;  
            pupilDiam = 4   'Default pupil diameter $=9g,39  
        Else Yn_v'Os2  
            pupilDiam = CDbl(dlg.TextBox2) `C&@6{L  
        End If ii5dTimRJ  
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        Print " " &SW~4{n:  
        Print "Accommodation = " & A & " Diopters" K'c[r0Ew  
        Print "Pupil Diameter = " & pupilDiam & " mm" 3E-dhSz:i  
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        ' Calculate new parameters with accommodation m4on<5s/  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness fzJ^`  
    +C36OcmT~  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens 0 K(&EpVE  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens adtgNwg  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens .)c+gyaQ  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens szs.B|3X@*  
    ZA7b;{o [  
        tlens = 3.767 + 0.04*A                  'Lens thickness  GUps\:ss  
    7Tc^}Q  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction !!<H*9]+W;  
    [{q])P;  
        'Adjust parameters to account for accommodation &a'mh  
    q\G7T{t$.  
        '************************************************************************* ?&JK q^9\I  
        'Aqueous thickness (Position of Lens) cB6LJ}R  
        '************************************************************************* Gm[XnUR7V  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) BC)1FxsGf  
        GetCustomElement eID, entity IP!`;?T=  
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        parID = FindFullName( "Geometry.Arizona Eye" ) i<M F8 $  
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        ' Delete any shift(s) in z @Yw>s9X  
        count = 0 6Zx)L|B  
        While GetOperationCount(eID)>count wz{&0-md*'  
            GetOperation eID, count, op 2-%9k)KH  
            If op.Type="ShiftZ" Then !}hG|Y6s  
                DeleteOperation eID,count avY<~-44B  
                count=count-1 ig^x%!;  
            End If 8'Iei78Ov  
            count=count+1 1oI2  
        Wend : j`4nXm  
    39bw,lRPV  
        'Set new shift in I&f!>y?,Z  
        op.Type = "ShiftZ" !>:]k?$b  
        op.val1 = taq *{(tg~2'(  
        op.parent = parID L5 wR4Ue)  
        AddOperation eID, op p^s:s-"f\  
        Print "Set aqueous humor thickness = " & taq-0.55 M7=|N:/_  
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        '************************************************************************* y9~:[jB  
        'Radius and conic constant of anterior lens K(AZD&D  
        '************************************************************************* 6J <.i  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Ud_0{%@  
        GetConic eID, entity, curv, conic {$I1(DYN  
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        SetConic eID, entity, 1/Rant, CCant 'yR\%#s6  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant t4UL|fI  
    s)#TT9BbV  
        '************************************************************************* :)F0~Q  
        'Radius and conic constant of posterior lens |#sY(1  
        '************************************************************************* U^kk0OT^  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ),lE8A{ H  
        GetConic eID, entity, curv, conic k54b@U52 h  
    ,+v>(h>q  
        SetConic eID, entity, 1/Rpost, CCpost 825 QS`  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost y;f nC5Q  
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        '************************************************************************* WO*dO9O  
        'Lens thickness (Position of posterior lens surface) NbK67p:  
        '************************************************************************* lL,0IfC,  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) $XcuU sG  
    Y+gNi_dE  
        ' Delete any z-shift(s) _e "  
        count = 0 xmejoOF  
        While GetOperationCount(eID)>count fs2y$HN  
            GetOperation eID, count, op 5Vr#>W  
            If op.Type="ShiftZ" Then esd9N'.Q*  
                DeleteOperation eID,count bUe6f,8,  
                count=count-1 ^*F'[!. p  
            End If C?]+(P  
            count=count+1 QtLd(& !v  
        Wend %>1C ($^  
    YoSBS   
        'Set new z-shift QC(ce)Y  
        op.Type = "ShiftZ" e\ }'i-  
        op.val1 = tlens HE-ErEtGB  
        op.parent = parID MADt$_  
        AddOperation eID, op dB8 e  
        Print "Set lens thickness = " & tlens (Ft#6oK"  
    NYeL1h)l  
        '************************************************************************* e"ClG/M_XS  
        'Lens index of refraction > 0c g  
        '************************************************************************* ^xq)Q?[{  
        eID = FindMaterial( "Lens" ) L$?YbQo7  
        GetModelMaterial eID, mat d~y]7h|  
    j rg B56LL  
        mat.Nd = nlens QEP|%$:i  
        SetModelMaterial eID, mat 8 -9<r  
        Print "Set lens index of refraction = " & nlens ;".]W;I*O  
    }x:}9iphF  
        '************************************************************************* ,qIut|C*  
        'Pupil diameter cK75Chsu  
        '************************************************************************* $ Zj3#l:rK  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) " t,ZO  
    OKnpG*)u=g  
        'Adjust pupil diameter (trimming volume inner hole) 9 xFX"_J  
    7|<-rjz^  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 58]t iP"  
    Mlo:\ST|  
        ' Adjust pupil location to just in front of the lens ooj^Z%9P  
        parID = FindFullName( "Geometry.Arizona Eye" ) E0eZal],  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 1n#{c5T  
        count = 0 mzcxq:uZ5  
        While GetOperationCount(eID)>count Y r8gKhv W  
            GetOperation eID, count, op Fu65VLKh  
            If op.Type="ShiftZ" Then 8O0]hz  
                DeleteOperation eID,count c#a>> V  
                count=count-1 2,p= %  
            End If |9mGX9q  
            count=count+1 @1V?94T1  
        Wend n M `pnR_  
        op.Type = "ShiftZ" `rpmh7*WV  
        op.val1 = taq-0.01 ?$=Ml$  
        op.parent = parID F ZN}T{<  
        AddOperation eID, op B~%SB/eu  
    nr%P11U\c  
        Print "Set pupil diameter = " & pupilDiam >(W\Eh{J  
    y7LM}dH#m  
        'Update AZ Eye subassembly Description ZSn6JV'g  
        eID = FindFullName( "Geometry.Arizona Eye" ) e*39/B0S  
        GetEntity eID, entity 1r<'&f5  
        entity.Description = "Accommodation = " & A & "D" SA~oGgk=P  
        SetEntity eID, entity 4TcW%  
    G$jw#a[L  
        Update 7 ;x to =  
        Print "DONE!" ;e Mb$px  
         2 '8I/>-  
    End Sub /Tp>aW%}"  
    sd |c/ayh~  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: 1Ch0O__2L  
    qcfg 55]'c  
    Accommodation = 4 Diopters , 1il&  
    Pupil Diameter = 4 mm lht :%Ts$  
    Set aqueous humor thickness = 2.81 !lI1jb"  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 !uhh_3RH  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 :(i=> ~O  
    Set lens thickness = 3.927 Zc=#Y  
    Set lens index of refraction = 1.42672 hho\e 8  
    Set pupil diameter = 4 Pa/2])w  
    DONE! SKJ'6*6  
     
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