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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 p%#=OtkC  
    /VHQ!Wi  
    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。 <tI_u ~P  
    t2_pwd*B  
    模型 XtftG7r9S  
    L a8D%N  
    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。 G_v^IM#B=  
    *5z"Xy3J  
    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. <7*d2  
    tdOox87YK  
    光源 9?I?;l{  
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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。 EY}*}-3  
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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。 P*g:rg  
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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|@kF!6  
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    图2. 字母F光源的设定方法光 Q60'5Wt  
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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 W0\ n?$ZC~  
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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。 #<81`%  
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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。 i'MpS  
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    图5. 视网膜重点采样规格设定
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    脚本 @WTzFjv@?4  
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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: 1+9}Xnxb  
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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。 H{+[ ,l  
    余下的脚本计算与屈光度有关的所有参数。 OYj~"-3y)  
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    分析 N'=b8J-fF  
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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。  li  
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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 Fh~ pB>t  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. kA{eT  
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    Dim entity As T_ENTITY p{w:^l(  
    Dim op As T_OPERATION nrJW.F]S8[  
    Dim mat As T_MODELMATERIAL s/0~!0  
    Dim A As Double !d{Ijs'T  
    Dim pupilDiam As Double ^wMZG'/  
    Dim eID As Long de,4M s!%  
    Dim parID As Long N&]_U%#Q  
    Dim count As Integer Qkx}A7sK  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double r%vO^8FQ  
    Dim tlens As Double, nlens As Double x?n13C  
    Dim curv As Double, conic As Double WNo<0|X  
    Dim ok As Long L /V;;  
    #s0Wx47~  
    Sub Main Y%#r&de  
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        '用户输入对话框 F~zrg+VDjL  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 YTV|]xpR  
            TextBox 220,21,40,21,.TextBox1 'default: 0 e8VtKVcY  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 I@l }%L  
            OKButton 40,91,90,21 y/OPN<=*  
            CancelButton 190,91,90,21 c-=z<:Kf  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 cp L'  
            TextBox 220,49,40,21,.TextBox2 'default: 4 <gjA(xT5  
        End Dialog }J(o!2.  
        Dim dlg As UserDialog IpKpj"eoLy  
    lvk r2Meu<  
        ok = Dialog (dlg) *IV_evgM7  
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        If ok=0 Then    'cancel button was pressed dobqYd4`  
            Print "Execution cancelled." M:cW/&ZJ  
            End <a)L5<#  
        End If ghDOz 3  
    w/Y6m.i1  
        'Assign accommodation and pupil diameter & use defaults if field left empty F.@U X{J  
        If dlg.TextBox1 = "" Then <S(`e/#[  
            A = 0           'Default accommodation %C~LKs5oH  
        Else /=~o|-n8@  
            A = CDbl(dlg.TextBox1) #6F/:j;  
        End If a:}&v^v  
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        If dlg.TextBox2 = "" Then faPgp  
            pupilDiam = 4   'Default pupil diameter ;*q  
        Else q+cx.Rc#  
            pupilDiam = CDbl(dlg.TextBox2) Z{rD4S @^  
        End If !y-,r4\@`  
    YZQF*fj  
        Print " " >SaT?k1E  
        Print "Accommodation = " & A & " Diopters" ;}QM#5Xdt  
        Print "Pupil Diameter = " & pupilDiam & " mm" GcCMCR3  
    B| .8+Q  
        ' Calculate new parameters with accommodation Pef$-3aP>E  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness DY?;Z98P?  
    hp!. P1b  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens q+?>shqsZ  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ))eQZ3ap9  
    y)0wM~E;2  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens g"|Z1iy|9  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Oj0,Urs7  
    N]7#Q.(~  
        tlens = 3.767 + 0.04*A                  'Lens thickness }4wIfI83K,  
    $}z%}v  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction khS >  
    RZ GD5`n  
        'Adjust parameters to account for accommodation :%kJ9zW  
    dBM> ;S;v  
        '************************************************************************* U!Eo*?LU$  
        'Aqueous thickness (Position of Lens) m5KAKpCR,  
        '************************************************************************* _~a5;[~  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) hH*/[|z  
        GetCustomElement eID, entity 4j VFzO%.  
    #SIIhpjA(  
        parID = FindFullName( "Geometry.Arizona Eye" ) :+$/B N:iO  
    n s`njx}C  
        ' Delete any shift(s) in z xa$p,_W:'  
        count = 0 O [v(kH'  
        While GetOperationCount(eID)>count _MST8  
            GetOperation eID, count, op s7G!4en  
            If op.Type="ShiftZ" Then qTi%].F"G  
                DeleteOperation eID,count 2%gLq  
                count=count-1 d|RDx;r l8  
            End If i)mQ?Y#o  
            count=count+1 qe_59'K  
        Wend Ld$e  -dB  
    d;WXlE;  
        'Set new shift in o.M.zkP a  
        op.Type = "ShiftZ" *7:HO{P>Y  
        op.val1 = taq ;+Uc} =  
        op.parent = parID C Ch38qBp  
        AddOperation eID, op %MUh_63bB  
        Print "Set aqueous humor thickness = " & taq-0.55 a?5R ;I B  
    5"o)^8!>  
        '************************************************************************* } D0Y8  
        'Radius and conic constant of anterior lens #Y;tobB  
        '************************************************************************* A.>TD=Nz  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) &<\i37y  
        GetConic eID, entity, curv, conic N9jSiRJ  
    \o2cztl=  
        SetConic eID, entity, 1/Rant, CCant "j] r   
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant iQj2aK Gs  
    Ub9p&=]h  
        '************************************************************************* o u*`~K|R  
        'Radius and conic constant of posterior lens \Cz uf   
        '************************************************************************* ds|L'7  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) UKfpoDhEe  
        GetConic eID, entity, curv, conic DP<[Uz&  
    $9m>(b/;n  
        SetConic eID, entity, 1/Rpost, CCpost ]5`Y^hS_g  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ._5"FUg  
    B jsF5~+\  
        '************************************************************************* }!n90 9 L  
        'Lens thickness (Position of posterior lens surface) t9(sSl  
        '************************************************************************* gW(7jFl  
    B`1"4[{  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) =abBD   
    ;0 No@G;z  
        ' Delete any z-shift(s) <oP"kh<D4  
        count = 0 ,[t>N>10TH  
        While GetOperationCount(eID)>count B9(e"cMm  
            GetOperation eID, count, op PShluhY  
            If op.Type="ShiftZ" Then Al1BnFB  
                DeleteOperation eID,count wS%aN@ay3  
                count=count-1 XEvDtDR  
            End If Z{gJm9  
            count=count+1 p@Ng.HE  
        Wend  Lkl+f~m  
    ;*=MI/"N  
        'Set new z-shift <sNk yQ  
        op.Type = "ShiftZ" g9K7_T #W  
        op.val1 = tlens yYri.n  
        op.parent = parID lIDGL05f'  
        AddOperation eID, op +M %zOX/  
        Print "Set lens thickness = " & tlens $Z!7@_Ys  
    _(.,<R5  
        '************************************************************************* yB~` A>~M  
        'Lens index of refraction &hri4p/  
        '************************************************************************* =i:6&Y~VGq  
        eID = FindMaterial( "Lens" ) O!=ae|  
        GetModelMaterial eID, mat F^bzE5#  
    U#{^29ik=o  
        mat.Nd = nlens @& vtY._  
        SetModelMaterial eID, mat '4J];Nj0  
        Print "Set lens index of refraction = " & nlens U9ZWSDs  
    d9>k5!  
        '************************************************************************* ?}D|]i34  
        'Pupil diameter Q $5U5hb  
        '************************************************************************* $&l} ABn  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Dd:;8Xo  
    @cz\'v6E  
        'Adjust pupil diameter (trimming volume inner hole) tbr1mw'G  
    8LZmr|/F*  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 0>KW94  
    JE$aYs<(TF  
        ' Adjust pupil location to just in front of the lens q;{# ~<"+  
        parID = FindFullName( "Geometry.Arizona Eye" ) EX.`6,:+2  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) +o94w^'^$b  
        count = 0 5\6S5JyIL  
        While GetOperationCount(eID)>count (g>>   
            GetOperation eID, count, op yu>DVD  
            If op.Type="ShiftZ" Then u_~*)w+mS@  
                DeleteOperation eID,count 4LfD{-_uW  
                count=count-1 ',<B o{  
            End If Ka$YKY,  
            count=count+1 ~c*$w O\  
        Wend Np?%pB!Q  
        op.Type = "ShiftZ" B-`,h pp  
        op.val1 = taq-0.01 3TS(il9A  
        op.parent = parID %1Pn;bUU!  
        AddOperation eID, op ?%Pd:~4D  
    qbwX*E~ ;  
        Print "Set pupil diameter = " & pupilDiam zYW+Goz/C  
    f 4Yn=D=_  
        'Update AZ Eye subassembly Description `J(im  
        eID = FindFullName( "Geometry.Arizona Eye" ) ee0)%hc1t  
        GetEntity eID, entity )`sEdVxbr  
        entity.Description = "Accommodation = " & A & "D" G?t<4MT v  
        SetEntity eID, entity }%;o#!<N(@  
    tAM t7p-  
        Update x?unE@?\S  
        Print "DONE!" MI,b`pQ  
         N7b+GqYpF>  
    End Sub v[O}~E7'  
    !&k}YF  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: ? !dy  
    j m]d:=4_  
    Accommodation = 4 Diopters scsN2#D7U/  
    Pupil Diameter = 4 mm N5SePA\ ,?  
    Set aqueous humor thickness = 2.81 ^=lh|C\#  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 VW[!%<  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 R zOs,  
    Set lens thickness = 3.927 g2&%bNQ-5  
    Set lens index of refraction = 1.42672 1JFCYJy  
    Set pupil diameter = 4 $z>L $,c>  
    DONE! 5ZXP$.  
     
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