[技术]Arizona眼睛模型 [复制链接]

简介 |@nXlZE  
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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。 xPv&(XZR  
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模型 Fk:(%ci  
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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。 fA^O  
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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. EUgs2Fsb3  
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光源 -rfO"D>  
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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。 y;H 3g#  
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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。 rRW&29A  
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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。 _)Ms9RN  
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视网膜的散射 (|-/S0
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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。 Tm `CA0@  
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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。 [T|~Kh%#  
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脚本 l\eq/yg_  
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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： I4$a#;  
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如果“OK”按钮按下，将会核对对话框下面的代码行，如果点击取消则脚本终止。然后输入的参数赋予变量，如果此处是保留为空白，则使用默认值。因此，如果没有值输入并点击“OK”按钮，则脚本是以屈光度为0，光瞳直径为4mm来运行的。 B:l(`G  
余下的脚本计算与屈光度有关的所有参数。 
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分析 5VI'hxU4Qg  
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屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 #f[yp=uI:  
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脚本代码 Z^sO`C  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. UuN(+&oD-  
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Dim entity As T_ENTITY T+\BX$w/4e  
Dim op As T_OPERATION u3q!te  
Dim mat As T_MODELMATERIAL /];F4AO5  
Dim A As Double .w0?  
Dim pupilDiam As Double QF>H>=Za=  
Dim eID As Long \"5\hX~dS  
Dim parID As Long C'{Z?M>  
Dim count As Integer GovGh? X#x  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 8!1o,=I$  
Dim tlens As Double, nlens As Double E*kS{2NAq  
Dim curv As Double, conic As Double a+Q)~13  
Dim ok As Long _onHe"%
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Sub Main c;j]/R$i  
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    '用户输入对话框 (bXCc  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 M+Dkn3bx  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ?&?y-&.5-  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 HGPbx$!  
        OKButton 40,91,90,21 ,7eN m>$  
        CancelButton 190,91,90,21 (A1!)c  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 FrB19  
        TextBox 220,49,40,21,.TextBox2 'default: 4 LG;xZQx'  
    End Dialog ?L_#AdK  
    Dim dlg As UserDialog 2-8<uUy  
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    ok = Dialog (dlg) ,Qp58u2V  
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    If ok=0 Then    'cancel button was pressed ^b&aDm~(7  
        Print "Execution cancelled." Z#9{1sHEP  
        End 7bTs+
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    End If pxP7yJL`  
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    'Assign accommodation and pupil diameter & use defaults if field left empty q+SDJ?v  
    If dlg.TextBox1 = "" Then M5D,YC3<  
        A = 0           'Default accommodation  Wkf)4!  
    Else y1P?A]v  
        A = CDbl(dlg.TextBox1) (!;4Y82#  
    End If 3wD6,x-e   
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    If dlg.TextBox2 = "" Then J`\%'pEn  
        pupilDiam = 4   'Default pupil diameter zVp|%&  
    Else lO<Ujb#"R  
        pupilDiam = CDbl(dlg.TextBox2) BHa!jw_~o  
    End If y9:|}Vh  
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    Print " " a}MOhM6T  
    Print "Accommodation = " & A & " Diopters" {<&x9<f9  
    Print "Pupil Diameter = " & pupilDiam & " mm" x_#yH3kJ  
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    ' Calculate new parameters with accommodation >:8GU f*  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness : wb\N'b  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens oU67<jq  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens aMT&}3  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens W)o-
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    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens GT`:3L  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 6D) vY  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction !Il<'+ ^  
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    'Adjust parameters to account for accommodation r*y4Vx7  
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    '************************************************************************* s!uewS.  
    'Aqueous thickness (Position of Lens) KK/~W  
    '************************************************************************* =p ^Sn
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    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 0!\pS{$zB  
    GetCustomElement eID, entity yG{'hx6H  
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    parID = FindFullName( "Geometry.Arizona Eye" ) iwrS>Sm  
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    ' Delete any shift(s) in z Ig*!0(v5$  
    count = 0 [Nsv]Yz  
    While GetOperationCount(eID)>count Vtr0=-m&  
        GetOperation eID, count, op ]#KZ W)M  
        If op.Type="ShiftZ" Then J!~?}Fq/z  
            DeleteOperation eID,count >4b-NS/}0  
            count=count-1 `TBau:ElI  
        End If [iB`- dE,  
        count=count+1 dKi+~m'w  
    Wend g/J ^YT!  
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    'Set new shift in szGp<x
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    op.Type = "ShiftZ" FNtcI7  
    op.val1 = taq H~Hh$-z  
    op.parent = parID 8?J\  
    AddOperation eID, op e%u1O-*  
    Print "Set aqueous humor thickness = " & taq-0.55 \k;*Ej~.  
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    '************************************************************************* -}4<P}.5T  
    'Radius and conic constant of anterior lens VYMs`d[  
    '************************************************************************* ~;9B\fE`  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) H<Ed"-n$I<  
    GetConic eID, entity, curv, conic u#ag|b/C:  
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    SetConic eID, entity, 1/Rant, CCant mtvfG  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?1JS*LQ$  
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    '************************************************************************* IhhB^E|  
    'Radius and conic constant of posterior lens T&j_7Q\;vI  
    '************************************************************************* $i7iv  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) M\ B A+  
    GetConic eID, entity, curv, conic &>XIK8*  
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    SetConic eID, entity, 1/Rpost, CCpost OjcxD5"v9  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost =TE6R 0b  
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    '************************************************************************* {|9x*I  
    'Lens thickness (Position of posterior lens surface) MDM/~Qpj_  
    '************************************************************************* I&,gCZ#  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) %ZDo;l+<F6  
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    ' Delete any z-shift(s) R/VrBiw  
    count = 0 TO ^}z  
    While GetOperationCount(eID)>count pdUrVmW"'  
        GetOperation eID, count, op Yg3Vj=  
        If op.Type="ShiftZ" Then ""|vhgP  
            DeleteOperation eID,count .v?Ir)  
            count=count-1 8!(4;fN$j.  
        End If c*sK| U7)  
        count=count+1
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    Wend S:"R/EE(  
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    'Set new z-shift vN=e1\  
    op.Type = "ShiftZ" 38ChS.(  
    op.val1 = tlens y
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    op.parent = parID 2ys'q!  
    AddOperation eID, op z%Pbs[*C  
    Print "Set lens thickness = " & tlens BG\g`NK}Z  
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    '************************************************************************* -!zyit5B  
    'Lens index of refraction PQ9.aJdw@-  
    '************************************************************************* ;-Fr^|do y  
    eID = FindMaterial( "Lens" ) =B-a]?lM  
    GetModelMaterial eID, mat %eW[`uyV  
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    mat.Nd = nlens +n_`*@SE  
    SetModelMaterial eID, mat KjFNb;mM  
    Print "Set lens index of refraction = " & nlens n%yMf!M .:  
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    '************************************************************************* O{:_-eI&d  
    'Pupil diameter $Hh3*reSg-  
    '************************************************************************* vu-QyPnS|w  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) >*rH Nf  
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    'Adjust pupil diameter (trimming volume inner hole) 9)N/J\b  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" b~uz\%'3  
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    ' Adjust pupil location to just in front of the lens DG1C_hu i  
    parID = FindFullName( "Geometry.Arizona Eye" ) $n>|9(K8  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) vl+vzAd  
    count = 0 g|L" |Q  
    While GetOperationCount(eID)>count unn2MP'  
        GetOperation eID, count, op 0kEzi  
        If op.Type="ShiftZ" Then lW}"6@0,  
            DeleteOperation eID,count 4|i.b?"  
            count=count-1 vd+yU9  
        End If lrQ +G@#  
        count=count+1 
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    Wend M8j%bmd(,  
    op.Type = "ShiftZ" 2
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    op.val1 = taq-0.01 XoI,m8A  
    op.parent = parID Pt<lHfd  
    AddOperation eID, op G,,c,  
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    Print "Set pupil diameter = " & pupilDiam ,2h
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    'Update AZ Eye subassembly Description I|@'2z2  
    eID = FindFullName( "Geometry.Arizona Eye" )
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    GetEntity eID, entity `}uOlC]I  
    entity.Description = "Accommodation = " & A & "D" 1QkAFSl3  
    SetEntity eID, entity ^3`CP4DT  
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    Update QI\&D)  
    Print "DONE!" DxX333vC  
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End Sub oB$7m4xO\  
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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： 0>PO4WFVJ  
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Accommodation = 4 Diopters Mx& P^#B3  
Pupil Diameter = 4 mm \VJ7ahg[\  
Set aqueous humor thickness = 2.81 )./pS~  
Set anterior lens radius = 10.4 and conic constant = -2.375869 Sw!/IPO  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 _ElA\L4g%  
Set lens thickness = 3.927 "n'LF?/H'  
Set lens index of refraction = 1.42672 jTjGbC]X  
Set pupil diameter = 4 P8#;a  
DONE! .^]=h#[e