[技术]Arizona眼睛模型 [复制链接]

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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。 n{WJ.Y*  
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模型 .g?,:$`0D?  
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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。 DN0b.*[`3  
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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. ;CBdp-BUj  
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光源 =)5a=^ 6  
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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。 (.+n1)L?  
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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。 aC
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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。 U# B  
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视网膜的散射 RtL'fd  
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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。 Tyl"N{ _  
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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。 \M@8# k|  
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脚本 :nEV/"#F  
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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： jXZNr  
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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。 =1capix 1r  
余下的脚本计算与屈光度有关的所有参数。 pC8i&_A  
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分析
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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。 6'zy"UkH  
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脚本代码 -AQX-[
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. h6t>yC\  
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Dim entity As T_ENTITY oMbCljUC  
Dim op As T_OPERATION Ls{fCi/2F  
Dim mat As T_MODELMATERIAL 6 -}gqkR  
Dim A As Double [4e5(!e  
Dim pupilDiam As Double &EOh}O<  
Dim eID As Long {9MYEN}FO  
Dim parID As Long r N7"%dx  
Dim count As Integer ~T~v*'_h  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double :ux`*,zh  
Dim tlens As Double, nlens As Double ND>}t#^$  
Dim curv As Double, conic As Double p'*UM%@SIY  
Dim ok As Long |z%,W/Ef  
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Sub Main E.9F~&DPJ<  
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    '用户输入对话框 _?ZT[t<  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 U<b!$"P9  
        TextBox 220,21,40,21,.TextBox1 'default: 0 -,&Xp>u\  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 T_WQzEL^  
        OKButton 40,91,90,21 }UrtDXhA  
        CancelButton 190,91,90,21 wah`  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Qp
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        TextBox 220,49,40,21,.TextBox2 'default: 4 j^.P=;  
    End Dialog O
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    Dim dlg As UserDialog 6X7_QBC)  
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    ok = Dialog (dlg) i`~y%y  
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    If ok=0 Then    'cancel button was pressed [>;O'>  
        Print "Execution cancelled." U VT8TN-T  
        End xcig'4L  
    End If _,^sI%  
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    'Assign accommodation and pupil diameter & use defaults if field left empty DYS(ZY)4  
    If dlg.TextBox1 = "" Then |zMQe}R@%  
        A = 0           'Default accommodation d:D2[  
    Else ^4"
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        A = CDbl(dlg.TextBox1) 'SmdU1]4BD  
    End If Li2)~4p><  
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    If dlg.TextBox2 = "" Then abND#t  
        pupilDiam = 4   'Default pupil diameter VsC]z, o
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    Else #d~"bn q;c  
        pupilDiam = CDbl(dlg.TextBox2) P(`IY+  
    End If dY,'6JzC  
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    Print " " 'Khq!pC   
    Print "Accommodation = " & A & " Diopters" D1f=f88/}  
    Print "Pupil Diameter = " & pupilDiam & " mm" 0`W~
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    ' Calculate new parameters with accommodation
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    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ^tv*I~>J!  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens g@Zc'g/XB  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 9YJb~tuZ73  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens <R2  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Xk2  75Y  
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    tlens = 3.767 + 0.04*A                  'Lens thickness sqw _c{9  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction tT7$2 9  
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    'Adjust parameters to account for accommodation &[YG\8sxWa  
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    '************************************************************************* 6-3l6q  
    'Aqueous thickness (Position of Lens) "rXGXQu  
    '************************************************************************* Cn,jLy  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ctZW7  
    GetCustomElement eID, entity 9K49<u0O  
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    parID = FindFullName( "Geometry.Arizona Eye" ) vl#/8]0!  
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    ' Delete any shift(s) in z +,MzD'(D  
    count = 0 R9W(MLe58  
    While GetOperationCount(eID)>count eYagI  
        GetOperation eID, count, op *f(}@U  
        If op.Type="ShiftZ" Then 8{ep`$(K@  
            DeleteOperation eID,count /EC m  
            count=count-1 C.
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        End If /eI38>v  
        count=count+1 ESO(~X+  
    Wend 982$d<0%  
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    'Set new shift in \R<yja  
    op.Type = "ShiftZ" $d"6y  
    op.val1 = taq Xm*Dh#H  
    op.parent = parID WV8<gx`Q  
    AddOperation eID, op 9J?j2!D  
    Print "Set aqueous humor thickness = " & taq-0.55 #zXDh3%]a  
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    '************************************************************************* ;7hf'k  
    'Radius and conic constant of anterior lens +z4NxR   
    '************************************************************************* {5to;\.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) tly:$;K  
    GetConic eID, entity, curv, conic $exu}%  
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    SetConic eID, entity, 1/Rant, CCant /`1zkBj<&  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant $]Q_x?  
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    '************************************************************************* +Kk6|+5u  
    'Radius and conic constant of posterior lens dWp4|r  
    '************************************************************************* YFW+l~[#  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ,^
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    GetConic eID, entity, curv, conic 
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    SetConic eID, entity, 1/Rpost, CCpost 9A6ly9DIS  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 89L-k%R  
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    '************************************************************************* 
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    'Lens thickness (Position of posterior lens surface) 0{
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    '************************************************************************* -du+iOe?  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) S4|)N,#  
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    ' Delete any z-shift(s) Tv(s?T6f  
    count = 0 PKwx)! Rz  
    While GetOperationCount(eID)>count ic3qb<2  
        GetOperation eID, count, op ^wX_@?aKtt  
        If op.Type="ShiftZ" Then LJBoS]~  
            DeleteOperation eID,count M0^r!f>O  
            count=count-1 M~@\x]p >  
        End If 9)=as/o  
        count=count+1 Jus)cO#I  
    Wend {L8SDU{P  
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    'Set new z-shift :!3P4?a  
    op.Type = "ShiftZ" vbSz&+52;  
    op.val1 = tlens 6!bf,T
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    op.parent = parID Vbwbc5m}  
    AddOperation eID, op HHX9QebiST  
    Print "Set lens thickness = " & tlens wi9fYfuv3R  
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    '************************************************************************* YKk%lZ.8  
    'Lens index of refraction mX<D]Z<
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    '************************************************************************* *EotYT  
    eID = FindMaterial( "Lens" ) >s1HQSe66  
    GetModelMaterial eID, mat wngxVhu8Ld  
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    mat.Nd = nlens z\;kjI  
    SetModelMaterial eID, mat )Dv"seH.  
    Print "Set lens index of refraction = " & nlens `E}2|9  
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    '************************************************************************* Z3S\@_/;  
    'Pupil diameter A?_2@6Y^  
    '************************************************************************* /A_ IS`  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) GM@TWwG-B  
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    'Adjust pupil diameter (trimming volume inner hole) b?r0n]  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" & ??)gMM[  
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    ' Adjust pupil location to just in front of the lens {"@Bf<J#  
    parID = FindFullName( "Geometry.Arizona Eye" ) $i =-A  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) E fqa*,k  
    count = 0 D-[0^  
    While GetOperationCount(eID)>count d`^@/1tO  
        GetOperation eID, count, op y{kXd1,  
        If op.Type="ShiftZ" Then H9&?<j1n  
            DeleteOperation eID,count /0(4wZe~?  
            count=count-1 BL]^+KnP  
        End If _Jx?m  
        count=count+1 0V1kZ.  
    Wend NMOTWA}2  
    op.Type = "ShiftZ" /Fk0j
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    op.val1 = taq-0.01 +[*UC"  
    op.parent = parID 60hf)er  
    AddOperation eID, op G"J6X e  
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    Print "Set pupil diameter = " & pupilDiam tl#hCy  
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    'Update AZ Eye subassembly Description  gs9f2t  
    eID = FindFullName( "Geometry.Arizona Eye" ) J :,  
    GetEntity eID, entity [J:vSt  
    entity.Description = "Accommodation = " & A & "D" 1P6~IZVN  
    SetEntity eID, entity \f._I+gJ  
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    Update |rNm_L2  
    Print "DONE!" OD*DHC2rN]  
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End Sub <01MXT-  
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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： \2~.r/`1  

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Accommodation = 4 Diopters ` 3<#DZ;!  
Pupil Diameter = 4 mm 4N*^%  
Set aqueous humor thickness = 2.81 } 1c5#Ym  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ZtIK"o-|!  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 dU+1@_  
Set lens thickness = 3.927 Y/{Z`}  
Set lens index of refraction = 1.42672 V1(eebi|  
Set pupil diameter = 4 j8N
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DONE! #He:p$43