[技术]Arizona眼睛模型 [复制链接]

简介 "5:^aC]  
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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。 {8`V5:  
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模型 6%?bl{pN
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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。 Jse;@K5y  
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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. >.'rN>B+  
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光源 5~)m6]-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。 _gDEIoBp  
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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。 u~[=5r  
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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。 +$_.${uwV  
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视网膜的散射 -36pkC 6 \  
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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。 pHO,][VZ  
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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。 [3KP@'52k  
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脚本 b{X,0a{*  
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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： {|:ro!&  
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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。 e$ pXnMx7  
余下的脚本计算与屈光度有关的所有参数。 Ep }{m<8c  
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分析 _'OXrT#Q  
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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。 '+8`3['  
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脚本代码 u(kacQ7  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. "~:AsZ"7  
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Dim entity As T_ENTITY c}$C=s5 h}  
Dim op As T_OPERATION Qf=+%-$Y  
Dim mat As T_MODELMATERIAL ;^yR,32F  
Dim A As Double g+:Go9k!F  
Dim pupilDiam As Double r:xbs0 7  
Dim eID As Long 16pk4f8  
Dim parID As Long 4nvi7  
Dim count As Integer 3$TU2-x;g  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 3_5]0:?]-  
Dim tlens As Double, nlens As Double KO!.VxG]_  
Dim curv As Double, conic As Double ;kE
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Dim ok As Long TAE@KSPvo  
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Sub Main 8k.<xWDU  
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    '用户输入对话框 d[( 
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    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 r9\7I7z  
        TextBox 220,21,40,21,.TextBox1 'default: 0 L9"yQD^R7?  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 -%
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        OKButton 40,91,90,21 XCAy _fL<B  
        CancelButton 190,91,90,21 vGST{Lz;  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Q"(*SA+-|  
        TextBox 220,49,40,21,.TextBox2 'default: 4 GJeP~   
    End Dialog ~R+,4  
    Dim dlg As UserDialog Vs"1:gi&  
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    ok = Dialog (dlg) AuW-XK.  
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    If ok=0 Then    'cancel button was pressed p)k5Uh"  
        Print "Execution cancelled." QT<\E`v  
        End 8mh@C6U  
    End If q4xP<b^  
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    'Assign accommodation and pupil diameter & use defaults if field left empty U)sw IisE  
    If dlg.TextBox1 = "" Then pRez${f.(s  
        A = 0           'Default accommodation J? 4E Hl  
    Else >;NiG)Z  
        A = CDbl(dlg.TextBox1) f_m~_`m  
    End If Z!81\5  
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    If dlg.TextBox2 = "" Then hN"cXz"/  
        pupilDiam = 4   'Default pupil diameter r:~q{  
    Else )?$zY5  
        pupilDiam = CDbl(dlg.TextBox2) FPC^-mD  
    End If tbm/gOBw  
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    Print " " Ij{ K\{y  
    Print "Accommodation = " & A & " Diopters" cAQ_/>  
    Print "Pupil Diameter = " & pupilDiam & " mm" 04E S>'@  
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    ' Calculate new parameters with accommodation \;FE@  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ny'wS  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens :RG=3T[  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens kBlk^=h<:w  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens $*S&i(z  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens J
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    tlens = 3.767 + 0.04*A                  'Lens thickness IA3m.Vxj ^  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction x T{s%wE  
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    'Adjust parameters to account for accommodation 9H%dK^C  
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    '************************************************************************* .:(T}\]R  
    'Aqueous thickness (Position of Lens) sz@Y$<o  
    '************************************************************************* dml,|k=  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 9.^2CM6l  
    GetCustomElement eID, entity -E+LA  
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    parID = FindFullName( "Geometry.Arizona Eye" ) QZ2a1f'G  
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    ' Delete any shift(s) in z !S}d?8I6  
    count = 0 8}.V[,]6  
    While GetOperationCount(eID)>count GWCU9n  
        GetOperation eID, count, op -& T.rsp  
        If op.Type="ShiftZ" Then Fu\!'\6  
            DeleteOperation eID,count -Crm#Ib~  
            count=count-1 Cb i;CF\{  
        End If '&<saqA  
        count=count+1 pp1kcrE\M  
    Wend K]H [A,  
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    'Set new shift in MnBHm!]&  
    op.Type = "ShiftZ" QqCwyK0  
    op.val1 = taq +&*Ybbhb  
    op.parent = parID Rl[SqmnI)@  
    AddOperation eID, op YGsg0I't  
    Print "Set aqueous humor thickness = " & taq-0.55 D&|HS!  

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    '************************************************************************* X 3(CY`HH[  
    'Radius and conic constant of anterior lens  PE&$2(  
    '************************************************************************* G"|c_qX  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" )  BRF4p:  
    GetConic eID, entity, curv, conic [+(fN  
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    SetConic eID, entity, 1/Rant, CCant 5XF&yYWq  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #%{x*y:Ms  
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    '************************************************************************* "YoFUfaNg  
    'Radius and conic constant of posterior lens LLU]KZhtY|  
    '************************************************************************* Nc\jA=  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ['DYP-1J  
    GetConic eID, entity, curv, conic Jie=/:&  
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    SetConic eID, entity, 1/Rpost, CCpost &2//\Qz  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Xp?WoC N  
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    '************************************************************************* U`kO<ztk  
    'Lens thickness (Position of posterior lens surface) ^wW{7Uq>  
    '************************************************************************* =(Pk7{  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) V\P .uOI  
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    ' Delete any z-shift(s) IiZXIG4H  
    count = 0 :IRQouTf:,  
    While GetOperationCount(eID)>count G`R_kg9$  
        GetOperation eID, count, op v])R6-T-  
        If op.Type="ShiftZ" Then ?(E?oJ)(  
            DeleteOperation eID,count M <ccfU!  
            count=count-1 4R28S]Gb  
        End If QB6. o6  
        count=count+1 4mwLlYZ  
    Wend C sx EN4  
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    'Set new z-shift #)z7&nD  
    op.Type = "ShiftZ" %+ur41HM  
    op.val1 = tlens Dy^A??A[E}  
    op.parent = parID :,pdR>q%(y  
    AddOperation eID, op Je#vu`.\\  
    Print "Set lens thickness = " & tlens Hr!%L*h?  
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    '************************************************************************* |6T"T P  
    'Lens index of refraction >+F +"NAN  
    '************************************************************************* OJ,Z  
    eID = FindMaterial( "Lens" ) &O|qx~(  
    GetModelMaterial eID, mat R:Tv'I1-L  
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    mat.Nd = nlens (/gMtIw  
    SetModelMaterial eID, mat ~5 e 1&  
    Print "Set lens index of refraction = " & nlens eJ_$Etc  
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    '************************************************************************* #p/'5lA&j  
    'Pupil diameter ]Ag{#GJ5D  
    '************************************************************************* )!g@MHHL  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ~vstuRRST  
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    'Adjust pupil diameter (trimming volume inner hole) yYPFk  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" X,ok3c4X  
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    ' Adjust pupil location to just in front of the lens !Tu4V\^~A  
    parID = FindFullName( "Geometry.Arizona Eye" ) LT6VZ,S  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) dZ"d`M>o6  
    count = 0 KK41I8Mw  
    While GetOperationCount(eID)>count +Q&CIo  
        GetOperation eID, count, op 0&2eiMKG?n  
        If op.Type="ShiftZ" Then a.B<W9$`  
            DeleteOperation eID,count ^s6C']q *O  
            count=count-1 [J+]1hCZ|  
        End If N7}yU~j^  
        count=count+1 "<1-9CMl  
    Wend "-A@d&5.  
    op.Type = "ShiftZ" eN-lz_..7  
    op.val1 = taq-0.01 @2R+?2 j  
    op.parent = parID XDAwE  
    AddOperation eID, op 8npjQ;%4>  
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    Print "Set pupil diameter = " & pupilDiam D}L4uz?  
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    'Update AZ Eye subassembly Description (m&''yaH  
    eID = FindFullName( "Geometry.Arizona Eye" ) -r@/8"  
    GetEntity eID, entity ^ Mw=!n[  
    entity.Description = "Accommodation = " & A & "D" Z$
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    SetEntity eID, entity ^5~)m6=2  
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    Update kf2e-)uUs  
    Print "DONE!" K])| V  
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End Sub O*-sSf   
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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： Zm#qW2a]P  
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Accommodation = 4 Diopters nQM7@"R  
Pupil Diameter = 4 mm n8 e4`-cY  
Set aqueous humor thickness = 2.81 )kK" 1\m  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ">r
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Set posterior lens radius = -4.424557 and conic constant = -3.081019 n^$HC=}S  
Set lens thickness = 3.927 kq=tL@W`0}  
Set lens index of refraction = 1.42672 iYl$25k/1  
Set pupil diameter = 4 eVB.g@%T  
DONE! _~_6qTv-d