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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 u(~(+1W  
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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。 Yq%r\[%*  
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模型 &G_XgQsg{  
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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。 iz2;xa*  
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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. K}tC8D  
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光源 D:XjJMW3r  
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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。 >(F y6m  
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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\ u  
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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。  \1?:  
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图2. 字母F光源的设定方法光 1(qL),F;  
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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 QoS]QY'bZ  
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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。 ~y1k2n  
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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。 -qpe;=g&f  
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图5. 视网膜重点采样规格设定
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脚本 &W N R{  
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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: m,r>E%;Cj  
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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。 Zi.w+V  
余下的脚本计算与屈光度有关的所有参数。 GoPK. E$  
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分析 =]P|!$!}0  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 <Gz*2i  
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图7. 字母F在视网膜上颜色分析
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脚本代码 G9h Bp  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 1V ; ,ZGI*  
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Dim entity As T_ENTITY #XeabcOQ  
Dim op As T_OPERATION 2Y%E.){  
Dim mat As T_MODELMATERIAL .gA4gI1kH  
Dim A As Double .>@]Im  
Dim pupilDiam As Double B2,JfKk/  
Dim eID As Long td|O#R  
Dim parID As Long A<{&?_U  
Dim count As Integer qoOq47F  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double RNb"O{3  
Dim tlens As Double, nlens As Double cT# R B7  
Dim curv As Double, conic As Double 8v\^,'@  
Dim ok As Long TTz_w-68  
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Sub Main "PC9[i  
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    '用户输入对话框 k Hh0&~ (  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 [\.@,Y0j  
        TextBox 220,21,40,21,.TextBox1 'default: 0 {\ J%i|u  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 og|~:>FmJo  
        OKButton 40,91,90,21 + EM^  
        CancelButton 190,91,90,21 E~1"Nh  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 'E%+ O  
        TextBox 220,49,40,21,.TextBox2 'default: 4 V)cL=4G  
    End Dialog #)( D_*  
    Dim dlg As UserDialog rF=\H3`p3  
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    ok = Dialog (dlg) _hi8m o  
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    If ok=0 Then    'cancel button was pressed SHN'$f0Mb  
        Print "Execution cancelled." AI2@VvB  
        End Z1oUAzpj4  
    End If 8J8@0  
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    'Assign accommodation and pupil diameter & use defaults if field left empty Uw->5   
    If dlg.TextBox1 = "" Then 1D)=q^\I  
        A = 0           'Default accommodation jC L 1Bj  
    Else f9La79v  
        A = CDbl(dlg.TextBox1) $'Qv {  
    End If xRm~a-rp  
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    If dlg.TextBox2 = "" Then _r vO#h  
        pupilDiam = 4   'Default pupil diameter \Wf1b8FW  
    Else a<v!5\dq!  
        pupilDiam = CDbl(dlg.TextBox2) iKEHwm  
    End If 3ULn ]jA  
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    Print " " Oi\,clR^[o  
    Print "Accommodation = " & A & " Diopters" g)^g_4  
    Print "Pupil Diameter = " & pupilDiam & " mm" N_f>5uv  
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    ' Calculate new parameters with accommodation Y]H,rO  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness L'<.#(|  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens P6u%-#  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Y%@a~|  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens wZKEUJpQ  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens utBKl' `  
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    tlens = 3.767 + 0.04*A                  'Lens thickness ?a'P;&@7  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction (GbZt{.  
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    'Adjust parameters to account for accommodation 31~Rs?~f(  
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    '************************************************************************* "i~~Q'=7  
    'Aqueous thickness (Position of Lens) uui3jZ:  
    '************************************************************************* ZoroK.N4A%  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ~?uch8H  
    GetCustomElement eID, entity peGh-  
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    parID = FindFullName( "Geometry.Arizona Eye" ) eWTbHF  
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    ' Delete any shift(s) in z \Ea(f**2B  
    count = 0 5FwVR3,  
    While GetOperationCount(eID)>count L3y`*&e>  
        GetOperation eID, count, op i=X B0-  
        If op.Type="ShiftZ" Then A!^gF~5  
            DeleteOperation eID,count s.XLC43Rs  
            count=count-1 @V qI+5TA  
        End If +~eybm;  
        count=count+1 .|<+-Rsj  
    Wend >0.a#-u^  
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    'Set new shift in oO][X  
    op.Type = "ShiftZ" Geyj`t  
    op.val1 = taq C !6d`|  
    op.parent = parID :V^|}C#  
    AddOperation eID, op kyu PN<?  
    Print "Set aqueous humor thickness = " & taq-0.55 A,]%*kg2  
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    '************************************************************************* GNab\M.  
    'Radius and conic constant of anterior lens T9&bY>f?  
    '************************************************************************* >!%F$$  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) <^fvTb&*  
    GetConic eID, entity, curv, conic o 6A1;e  
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    SetConic eID, entity, 1/Rant, CCant xBg. QV  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant AQIBg9y7  
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    '************************************************************************* >j_N6B!  
    'Radius and conic constant of posterior lens %rq/&#jC  
    '************************************************************************* q@Oe}  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) (V9 ;  
    GetConic eID, entity, curv, conic DBk]2W|i  
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    SetConic eID, entity, 1/Rpost, CCpost 0. mS^g,M-  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost C}Ucyzfr,p  
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    '************************************************************************* ~9DD=5\  
    'Lens thickness (Position of posterior lens surface) p-JGDjR0G  
    '************************************************************************* $#/f+kble  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) -&JQdrs  
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    ' Delete any z-shift(s) ?OF9{$m3?  
    count = 0 1AAOg+Y@U"  
    While GetOperationCount(eID)>count ^b^}6L'Z  
        GetOperation eID, count, op eq,`T;  
        If op.Type="ShiftZ" Then aDZ]{;  
            DeleteOperation eID,count @"__2\ 0  
            count=count-1 ,'&H`h54  
        End If .T\_4C  
        count=count+1 9s&Tv&%VN  
    Wend = ow=3Ku  
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    'Set new z-shift 2./;i>H[u  
    op.Type = "ShiftZ" U *:E|'>  
    op.val1 = tlens ndS8p]P&o(  
    op.parent = parID Usq.'y/ o  
    AddOperation eID, op )>I-j$%=2  
    Print "Set lens thickness = " & tlens *=(vIm[KL  
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    '************************************************************************* "?ON0u9  
    'Lens index of refraction i6)HC  
    '************************************************************************* :s>x~t8g#n  
    eID = FindMaterial( "Lens" ) ug^esB  
    GetModelMaterial eID, mat ~Aw.=Yi=  
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    mat.Nd = nlens cUC!'+L  
    SetModelMaterial eID, mat .X34[AXd  
    Print "Set lens index of refraction = " & nlens 2B"&WKk  
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    '************************************************************************* ' wni.E&  
    'Pupil diameter vW4n>h}]  
    '************************************************************************* qylI/,y{  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ZaF9Q%  
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    'Adjust pupil diameter (trimming volume inner hole) hGJANA  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" |H.ARLS  
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    ' Adjust pupil location to just in front of the lens L :Ldk  
    parID = FindFullName( "Geometry.Arizona Eye" ) :*Y2na)qQ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) V6Y0#sTU  
    count = 0 i>e?$H,/  
    While GetOperationCount(eID)>count `#"xgOSP>  
        GetOperation eID, count, op Y`rli  
        If op.Type="ShiftZ" Then H{hzw&dZ<P  
            DeleteOperation eID,count _{/[&vJ  
            count=count-1 {r'+icvLX  
        End If EYA=fU  
        count=count+1 U1O8u-X  
    Wend `T{'ufI4B  
    op.Type = "ShiftZ" 0ZJj5<U  
    op.val1 = taq-0.01 nx{MUN7  
    op.parent = parID PU8dr|!  
    AddOperation eID, op BhhFij4  
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    Print "Set pupil diameter = " & pupilDiam JJK-+a6cX  
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    'Update AZ Eye subassembly Description QD%!a{I  
    eID = FindFullName( "Geometry.Arizona Eye" ) 2'u%  
    GetEntity eID, entity +t3o5&  
    entity.Description = "Accommodation = " & A & "D" " =6kH,  
    SetEntity eID, entity Xw3j(`w$,  
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    Update SEVB.;  
    Print "DONE!" h"nhDART<  
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End Sub Zz"8  
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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: p6!5}dD(  
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Accommodation = 4 Diopters w!'y,yb%  
Pupil Diameter = 4 mm xkv%4H>  
Set aqueous humor thickness = 2.81 7ug"SV6Hb  
Set anterior lens radius = 10.4 and conic constant = -2.375869 hQ'W7EF  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 5z =}o/?  
Set lens thickness = 3.927 k7j.VpN9  
Set lens index of refraction = 1.42672 ln+.=U6Tm  
Set pupil diameter = 4 t+_\^Oa)  
DONE! p]ujip  
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