[技术]Arizona眼睛模型 [复制链接]

简介  H@sM$8  
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人眼光学模型可用来设计眼科用设备，光学系统注定了要与人眼一起使用。本文演示了这样一个模型：Arizona眼睛模型，在Jim Schwiegerling教授的书中有详细描述：《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源，并包括一个基于想要的屈光度来调整模型的内嵌脚本。 
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模型 8k^1:gt^  
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模型的定义如表1种所示，由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度（A）来决定。 k|cP]p4,  
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在FRED中使用0屈光度来创建的，光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. )4n]n:FjN  
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光源 fjm3X$tR  
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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。 0hq\{pw_y*  
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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。 .+~9 vH  
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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。 '2SZ]   
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视网膜的散射 G~/*!?&z  
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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。 fbkAu  
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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。 [o.#$(   
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脚本 q'%!qa+  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框，如下图所示： .GvZv>  
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如果“OK”按钮按下，将会核对对话框下面的代码行，如果点击取消则脚本终止。然后输入的参数赋予变量，如果此处是保留为空白，则使用默认值。因此，如果没有值输入并点击“OK”按钮，则脚本是以屈光度为0，光瞳直径为4mm来运行的。 ;ih;8  
余下的脚本计算与屈光度有关的所有参数。 !ozHS_  
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分析 R[H#av  
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屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 ^j<2s"S  
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脚本代码 avUdvV-  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. aQV?}  
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Dim entity As T_ENTITY |j4;XaG)  
Dim op As T_OPERATION cK'}+  
Dim mat As T_MODELMATERIAL R%Xz3Z&|  
Dim A As Double o>I,$=  
Dim pupilDiam As Double th+LScOX  
Dim eID As Long c\rP"y|S};  
Dim parID As Long EH]qYF.  
Dim count As Integer
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Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double b>nwX9Y/U  
Dim tlens As Double, nlens As Double @y,>cDg  
Dim curv As Double, conic As Double 3*oZol/  
Dim ok As Long ZJHaY09N  
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Sub Main LKst QP!I  
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    '用户输入对话框 \Lm`jU(:l  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1  mEbj  
        TextBox 220,21,40,21,.TextBox1 'default: 0 PsN_c[+  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 H2CpZK'  
        OKButton 40,91,90,21 KqXPxp^_Al  
        CancelButton 190,91,90,21 C%"aj^u  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Y\E7nll:.  
        TextBox 220,49,40,21,.TextBox2 'default: 4 z!)@`?  
    End Dialog Xkf|^-n  
    Dim dlg As UserDialog aO*v"^oF  
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    ok = Dialog (dlg) |^gnT`+  
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    If ok=0 Then    'cancel button was pressed "FLiSz%ME  
        Print "Execution cancelled." ccy q~  
        End _[N*k"  
    End If mH )i  
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    'Assign accommodation and pupil diameter & use defaults if field left empty , jCE hb  
    If dlg.TextBox1 = "" Then @R;&PR#5  
        A = 0           'Default accommodation
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    Else BxB B](  
        A = CDbl(dlg.TextBox1) JG{`tTu  
    End If !'>,37()  
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    If dlg.TextBox2 = "" Then c;88Wb<|W  
        pupilDiam = 4   'Default pupil diameter wM!dz&  
    Else ]aYuBoj  
        pupilDiam = CDbl(dlg.TextBox2) h/*@ML+bB8  
    End If iK8jX?  
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    Print " " 1+qP7 3a^  
    Print "Accommodation = " & A & " Diopters" /?*ut
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    Print "Pupil Diameter = " & pupilDiam & " mm" kT:?1w'  
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    ' Calculate new parameters with accommodation e /L([  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness n_*.i1\'w  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 7nZ3u_~  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens j2mMm/kq\  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens -cP1,>Ahv  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Pxgul7  
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    tlens = 3.767 + 0.04*A                  'Lens thickness `k(m2k?  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction `)TgGny01  
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    'Adjust parameters to account for accommodation vILgM\or  
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    '************************************************************************* \xmDkWzE  
    'Aqueous thickness (Position of Lens) p:3w8#)M
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    '************************************************************************* '30JJ0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) SME]C')7  
    GetCustomElement eID, entity lLI%J>b@  
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    parID = FindFullName( "Geometry.Arizona Eye" ) +R"n_6N  
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    ' Delete any shift(s) in z t;_1/mt  
    count = 0 l
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    While GetOperationCount(eID)>count EBpg  
        GetOperation eID, count, op w{GEWD{&  
        If op.Type="ShiftZ" Then VOT9cP^6  
            DeleteOperation eID,count l`a_0  
            count=count-1 olK*uD'`  
        End If !(y(6u#  
        count=count+1 ovaX_d)cU  
    Wend zo@,>'m  
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    'Set new shift in )))AxgM  
    op.Type = "ShiftZ"
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    op.val1 = taq W!1 B~NH#  
    op.parent = parID V@K^9R,|  
    AddOperation eID, op ^}lL@Bd|  
    Print "Set aqueous humor thickness = " & taq-0.55 m/`L3@7Tt  
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    '************************************************************************* }&%&0$%  
    'Radius and conic constant of anterior lens ""h%RhcZ\  
    '************************************************************************* ^Zlbs goZ  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) AOx8OiqE:  
    GetConic eID, entity, curv, conic ".?y!VY  

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    SetConic eID, entity, 1/Rant, CCant GqgJ]m  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant  !>Q{co'  
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    '************************************************************************* R9UC0D:-x  
    'Radius and conic constant of posterior lens  nWUau:%  
    '************************************************************************* u3sr
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    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ac8su0  
    GetConic eID, entity, curv, conic ?28)l 4 Ml  
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    SetConic eID, entity, 1/Rpost, CCpost sR| /s3;  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost :)Da^V  
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    '************************************************************************* )2r_EO@3HP  
    'Lens thickness (Position of posterior lens surface) am/D$
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    '************************************************************************* ,.&D{$1W  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) NU[Wj uLG  
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    ' Delete any z-shift(s) DXK\3vf Ot  
    count = 0 7*4i0{]  
    While GetOperationCount(eID)>count NC|VZwQtm  
        GetOperation eID, count, op w7~&Xxa/  
        If op.Type="ShiftZ" Then A64c,Uv  
            DeleteOperation eID,count EpENhC0  
            count=count-1 z0T6a15f!P  
        End If s*vtCdrE.  
        count=count+1 ryTtGx%a  
    Wend {3 >`k.w  
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    'Set new z-shift =HMuAUa.  
    op.Type = "ShiftZ" ca%XA|_J  
    op.val1 = tlens o^u}(wZ{  
    op.parent = parID c32"$g  
    AddOperation eID, op M$3/jl*#}  
    Print "Set lens thickness = " & tlens H+Q_%%[N  
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    '************************************************************************* RMAbu*D0  
    'Lens index of refraction y <P1VES  
    '************************************************************************* Q|Nw @7$`  
    eID = FindMaterial( "Lens" ) TaZlfe5z  
    GetModelMaterial eID, mat I2?
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    mat.Nd = nlens DMT2~mh  
    SetModelMaterial eID, mat %3q7i`AZ  
    Print "Set lens index of refraction = " & nlens Bc}e ??F  
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    '************************************************************************* '@#l/9
 
    'Pupil diameter UDb  
    '************************************************************************* EtDzmpJR>  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ^0/!:*?  
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    'Adjust pupil diameter (trimming volume inner hole) g]._J  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ['I5(M@  
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    ' Adjust pupil location to just in front of the lens  "-G&]YMl  
    parID = FindFullName( "Geometry.Arizona Eye" ) J#G\7'?{  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) > Cx;h=  
    count = 0 S#|5&SR  
    While GetOperationCount(eID)>count z!^3%kJJ>  
        GetOperation eID, count, op EyV6uk~  
        If op.Type="ShiftZ" Then kk aS&r>  
            DeleteOperation eID,count \X;)Kt"  
            count=count-1 ~<=wTns!  
        End If =`wnng5m  
        count=count+1 3L;&MG=  
    Wend OI)/J;[-e  
    op.Type = "ShiftZ" HE3x0H}o>  
    op.val1 = taq-0.01 ra{HlB{  
    op.parent = parID 2}.EFQp+  
    AddOperation eID, op ( z.\,M  
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    Print "Set pupil diameter = " & pupilDiam $p.0[A(N  
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    'Update AZ Eye subassembly Description y?V#LW[^E  
    eID = FindFullName( "Geometry.Arizona Eye" ) m# I  
    GetEntity eID, entity A<cnIUW  
    entity.Description = "Accommodation = " & A & "D" o&rNM5:  
    SetEntity eID, entity ~)!vhdBe  
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    Update h?&S*)1  
    Print "DONE!" 5i&+.?(Z=  
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End Sub 8MCSU'uQ  
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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： 9X87"  
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Accommodation = 4 Diopters 6s&%~6J,  
Pupil Diameter = 4 mm ziD+% -  
Set aqueous humor thickness = 2.81 Rm=[Sj84  
Set anterior lens radius = 10.4 and conic constant = -2.375869 = k>ygD_  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 mV'
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Set lens thickness = 3.927 [214b=  
Set lens index of refraction = 1.42672 =/qj vY  
Set pupil diameter = 4 ~@EBW3>~5  
DONE! X:gE mcXc