[技术]Arizona眼睛模型 [复制链接]

简介 sLk-x\P]|  
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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。 |.dRily+  
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模型 3so%gvY.'  
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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。 v$9y,^p@e  
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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. :4|4=mkr  
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光源 '3;b@g,  
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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。 lTsjxw
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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。 O/
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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。 2mU.7!g)  
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视网膜的散射 -\MG}5?!  
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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。 Hr C+Yjp  
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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/.6>4tE:  
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脚本 wuBPfb  
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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： ry]l.@o;  
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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。 \7_y%HR  
余下的脚本计算与屈光度有关的所有参数。 I=#$8l.*  
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分析 Ul#
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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。 >mkFV@`  
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脚本代码 %2h>-.tY  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. dWW.Y*339  
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Dim entity As T_ENTITY 'fW-Y!k%  
Dim op As T_OPERATION HKeK<V  
Dim mat As T_MODELMATERIAL Bp{Ri_&A  
Dim A As Double tX[WH\(xI  
Dim pupilDiam As Double d_CT$  
Dim eID As Long )PZT4jTt  
Dim parID As Long SfR%s8c`  
Dim count As Integer j1Ezf=N6`  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double w(F%^o\  
Dim tlens As Double, nlens As Double afk>+4q  
Dim curv As Double, conic As Double d5-qZ{W  
Dim ok As Long 3gzXbP,  
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Sub Main M\=2uKG#
 
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    '用户输入对话框 ?
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    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 @nf
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        TextBox 220,21,40,21,.TextBox1 'default: 0 DwF hK*  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 V)4J`xg^  
        OKButton 40,91,90,21 31)&vf[[  
        CancelButton 190,91,90,21 JS77M-Ac  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Wl4%GB  
        TextBox 220,49,40,21,.TextBox2 'default: 4 h];I{crh  
    End Dialog 8Y?;x}  
    Dim dlg As UserDialog V8(-  
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    ok = Dialog (dlg) u:EiwRW  
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    If ok=0 Then    'cancel button was pressed z{>Rc"%\  
        Print "Execution cancelled." mc3"`+o  
        End $!DpjN  
    End If 11lsf/IP  
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    'Assign accommodation and pupil diameter & use defaults if field left empty _f{{( 7  
    If dlg.TextBox1 = "" Then &{i{XcqH'  
        A = 0           'Default accommodation 0$njMnB2l  
    Else SAz   
        A = CDbl(dlg.TextBox1) KSL`W2}  
    End If I_BJH'!t  
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    If dlg.TextBox2 = "" Then =lC7gS!U  
        pupilDiam = 4   'Default pupil diameter bZ6+,J  
    Else +h$ 9\  
        pupilDiam = CDbl(dlg.TextBox2) m kexc~l  
    End If uw7zWJ n  
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    Print " " 54/=G(F  
    Print "Accommodation = " & A & " Diopters" IK]d3owA  
    Print "Pupil Diameter = " & pupilDiam & " mm" YS ][n_  
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    ' Calculate new parameters with accommodation Uz7<PLxd  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness W%J\qA  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 5X+A"X ;C  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens qb4z T
 
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens BuwY3F\-O  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens UI#h&j5pW  
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    tlens = 3.767 + 0.04*A                  'Lens thickness fZ. ONq  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction _g.{MT
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    'Adjust parameters to account for accommodation 1"g<0 W  
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    '************************************************************************* AR=]=8  
    'Aqueous thickness (Position of Lens) $C\BcKlmv  
    '************************************************************************* ZW}_DT0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5m*,8]!-  
    GetCustomElement eID, entity oQ#8nu{k  
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    parID = FindFullName( "Geometry.Arizona Eye" ) PM+[,H  
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    ' Delete any shift(s) in z Uv.)?YeGh  
    count = 0 HDLk>_N_s,  
    While GetOperationCount(eID)>count kFB  
        GetOperation eID, count, op YMgNzu  
        If op.Type="ShiftZ" Then _LPHPj^Pg  
            DeleteOperation eID,count 9my^Y9B  
            count=count-1 uS-|wYE  
        End If P'2Qen*  
        count=count+1 99S^f:t  
    Wend e!Hhs/&!T  
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    'Set new shift in
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    op.Type = "ShiftZ" {FGj]*  
    op.val1 = taq M{\I8oOg  
    op.parent = parID s>en  
    AddOperation eID, op RpK@?[4s  
    Print "Set aqueous humor thickness = " & taq-0.55 R2;  
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    '************************************************************************* hc1N~$3!G  
    'Radius and conic constant of anterior lens 8QK&
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    '************************************************************************* TJN4k@\$2  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Tk>#G{Wb-  
    GetConic eID, entity, curv, conic H[gWGbPq7  
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    SetConic eID, entity, 1/Rant, CCant 9z0p5)]n>  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 4JE
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    '************************************************************************* ),)lzN%!  
    'Radius and conic constant of posterior lens O8o3O 6[Y  
    '************************************************************************* C+]I@Go'Tk  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) /{[o~:'p  
    GetConic eID, entity, curv, conic lk!@?  
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    SetConic eID, entity, 1/Rpost, CCpost j+!v}*I![  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost FlQGgVN  
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    '************************************************************************* \GBuWY3B  
    'Lens thickness (Position of posterior lens surface) ==B6qX8T  
    '************************************************************************* 5s XXM  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) No$3"4wk  
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    ' Delete any z-shift(s) UBs4K*h|  
    count = 0 $:6!H:ty  
    While GetOperationCount(eID)>count Y@v>FlqI{  
        GetOperation eID, count, op =%7-ZH9  
        If op.Type="ShiftZ" Then +mPx8P&%  
            DeleteOperation eID,count ^pS~Z~[d/  
            count=count-1 TrNF=
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        End If yVfC-Z  
        count=count+1 =AT."$r>  
    Wend ni<(K 0~  
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    'Set new z-shift 'R)Tn!6  
    op.Type = "ShiftZ" 6b,
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    op.val1 = tlens 7^Uv7<pw  
    op.parent = parID y} '@R$  
    AddOperation eID, op d5b% W3  
    Print "Set lens thickness = " & tlens zCA2X !7F  
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    '************************************************************************* rOYx b }1  
    'Lens index of refraction yauvXosX  
    '************************************************************************* ]|@^1we  
    eID = FindMaterial( "Lens" ) 54,er$$V  
    GetModelMaterial eID, mat / 1RpM]d  
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    mat.Nd = nlens =wJX0A|  
    SetModelMaterial eID, mat }\f0 A-  
    Print "Set lens index of refraction = " & nlens :0/7,i  
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    '************************************************************************* b>W%t  
    'Pupil diameter km(Po}  
    '************************************************************************* s~>}a  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) #tHK"20  
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    'Adjust pupil diameter (trimming volume inner hole) aXVFc5C\  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" y-k.U%  
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    ' Adjust pupil location to just in front of the lens GyIV Hby  
    parID = FindFullName( "Geometry.Arizona Eye" ) @~e5<:|5#  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) hxx.9x>ow  
    count = 0 6863xOv{T  
    While GetOperationCount(eID)>count mw!F{pw  
        GetOperation eID, count, op _t$sgz&  
        If op.Type="ShiftZ" Then 3]>| i  
            DeleteOperation eID,count /z!%d%"  
            count=count-1 F2WKd1U  
        End If w xH7?tsf  
        count=count+1 5R-6ji  
    Wend RN1_S  
    op.Type = "ShiftZ" dG{A~Z z  
    op.val1 = taq-0.01 :h$$J lP  
    op.parent = parID !VJoM,b8  
    AddOperation eID, op *|0 -~u%q  
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    Print "Set pupil diameter = " & pupilDiam D-c4EV  
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    'Update AZ Eye subassembly Description 8y L Y  
    eID = FindFullName( "Geometry.Arizona Eye" ) Z r8*et  
    GetEntity eID, entity y `UaB3q  
    entity.Description = "Accommodation = " & A & "D" uD'6mk*  
    SetEntity eID, entity M7T5 ~/4  
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    Update ,hVli/   
    Print "DONE!" %{|pj +  
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End Sub O?2DQY?jT  
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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： vt8By@]:  
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Accommodation = 4 Diopters ";F'~}bDA  
Pupil Diameter = 4 mm zfU{Kd  
Set aqueous humor thickness = 2.81 ;I}fBZ3  
Set anterior lens radius = 10.4 and conic constant = -2.375869 K-4PI+qQ\  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 t_^4`dW`  
Set lens thickness = 3.927 Y7|EIAU5Y  
Set lens index of refraction = 1.42672 +%'(!A?*`  
Set pupil diameter = 4 ]G\}k  
DONE! aUp g u"