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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 Wl}d6ZTm  
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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。 7\eN 8+  
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模型 wS#.W zp.w  
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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。 EG2NE,,r  
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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. $#1i@dI  
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光源 V`=#j[gX)=  
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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。 ?u"MsnCXYn  
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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。 pS;jrq I#  
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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。 =EgiV<6vcH  
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图2. 字母F光源的设定方法光 Oe5=2~4O  
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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 wz<YflF  
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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。 }mzM'9JH  
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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。 ^W{+?q'  
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图5. 视网膜重点采样规格设定
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脚本 T}jryN;J5  
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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: <p;cR` %uE  
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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。 u(S~V+<@Z  
余下的脚本计算与屈光度有关的所有参数。 ~m2tWi@  
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分析 X!KjRP\\  
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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。 s~W:N .}*  
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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 e p* (  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. J39,x=8LL  
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Dim entity As T_ENTITY VC,wQb1J/  
Dim op As T_OPERATION C(qqGK{  
Dim mat As T_MODELMATERIAL ~_OtbNj#  
Dim A As Double ;"l>HL:^  
Dim pupilDiam As Double Nz %{T  
Dim eID As Long W7r1!/ccj  
Dim parID As Long q^ lx03   
Dim count As Integer z'GYU=  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double )>abB?RZ  
Dim tlens As Double, nlens As Double AX! YB'm-  
Dim curv As Double, conic As Double ]U.1z  
Dim ok As Long h)2W}p{a4=  
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Sub Main  *(5y;1KU  
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    '用户输入对话框 \W Kly  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7m3|2Qv  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ?UuJk  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 2YI#J.6]H  
        OKButton 40,91,90,21 P0WI QG+  
        CancelButton 190,91,90,21 :d\ne  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 sJu^deX  
        TextBox 220,49,40,21,.TextBox2 'default: 4 o\6A]T=R  
    End Dialog ^o^[p %  
    Dim dlg As UserDialog R%B"Gtl)  
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    ok = Dialog (dlg) OW!cydA-  
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    If ok=0 Then    'cancel button was pressed r6k0=6i  
        Print "Execution cancelled." O&h3=?O&B  
        End z=C'qF`  
    End If wn2+4> |~p  
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    'Assign accommodation and pupil diameter & use defaults if field left empty r:Uqtqxh  
    If dlg.TextBox1 = "" Then [gI;;GW  
        A = 0           'Default accommodation m:U.ao6  
    Else KZ_d..l*W  
        A = CDbl(dlg.TextBox1) r#ES|  
    End If 9ReH@5_bGM  
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    If dlg.TextBox2 = "" Then y\ Su!?4!  
        pupilDiam = 4   'Default pupil diameter yM}b  
    Else w;@DcX$]  
        pupilDiam = CDbl(dlg.TextBox2) (3PkTQlE  
    End If "f/91gIzm'  
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    Print " " P>q"P1&{  
    Print "Accommodation = " & A & " Diopters" "A\.`*6  
    Print "Pupil Diameter = " & pupilDiam & " mm" @ n<y[WA  
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    ' Calculate new parameters with accommodation fNjxdG{a  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness a|aRUxa0"  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens F-K=Ot j  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens :6R0=oz  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Bc1[^{`bq^  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens #m 2Ss  
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    tlens = 3.767 + 0.04*A                  'Lens thickness |KSd@   
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 4?Mb>\n%<^  
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    'Adjust parameters to account for accommodation :5 XNV6^|  
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    '************************************************************************* FCO5SX#-g  
    'Aqueous thickness (Position of Lens) %{GYTc \'X  
    '************************************************************************* nT UKA  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) [Y@?l]&  
    GetCustomElement eID, entity c6zghP3dR  
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    parID = FindFullName( "Geometry.Arizona Eye" ) YbS$D  
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    ' Delete any shift(s) in z BGAqg=nDV  
    count = 0 ~3p :jEM.[  
    While GetOperationCount(eID)>count ]WLQ q4q  
        GetOperation eID, count, op }9Yd[`  
        If op.Type="ShiftZ" Then ~~J xw ]  
            DeleteOperation eID,count rKZ1 c,y  
            count=count-1 WSA;p=_  
        End If \ ) H}  
        count=count+1 fAx7_}k/ m  
    Wend +RIG8w]  
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    'Set new shift in M9mC\Iz[  
    op.Type = "ShiftZ" ym*,X@Qg^  
    op.val1 = taq jpND"`Q  
    op.parent = parID H8^U!"~E  
    AddOperation eID, op n<Vq@=9AE  
    Print "Set aqueous humor thickness = " & taq-0.55 f"^G\  
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    '************************************************************************* <hG=0Zcr  
    'Radius and conic constant of anterior lens 2^-Z17Z}  
    '************************************************************************* 7D5;lM[_  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) +(>!nsf  
    GetConic eID, entity, curv, conic j@OGl&'^-  
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    SetConic eID, entity, 1/Rant, CCant Obl']Hr{y9  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant lZyxJDZ A  
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    '************************************************************************* gQ]WNJ~>  
    'Radius and conic constant of posterior lens JzhbuWwF-  
    '************************************************************************* t\[aU\4-7  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) j 8lWra\y  
    GetConic eID, entity, curv, conic 1Ql\aO)  
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    SetConic eID, entity, 1/Rpost, CCpost lWYZAF>?Ym  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost gQpF(P  
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    '************************************************************************* Vq7L:,N9  
    'Lens thickness (Position of posterior lens surface) Q~/TqG U  
    '************************************************************************* $s]c'D)  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) \Qa6mt2h  
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    ' Delete any z-shift(s) L0j&p[(r  
    count = 0 $6p_`LD0  
    While GetOperationCount(eID)>count JXR_klx  
        GetOperation eID, count, op aOWE\I c8  
        If op.Type="ShiftZ" Then J{98x zb  
            DeleteOperation eID,count E1,Sr?'  
            count=count-1 f< A@D"m/  
        End If Z,'#=K  
        count=count+1 !ueyVE$1  
    Wend d',OQ,~{  
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    'Set new z-shift &"bcI7uGT  
    op.Type = "ShiftZ" =ytB\e  
    op.val1 = tlens I?sA)!8  
    op.parent = parID I`%\ "bF@  
    AddOperation eID, op !P*1^8b`f  
    Print "Set lens thickness = " & tlens mp2J|!Lx  
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    '************************************************************************* \ Y[  
    'Lens index of refraction ]e0yC  
    '************************************************************************* >Le L%$  
    eID = FindMaterial( "Lens" ) OLAw Rha  
    GetModelMaterial eID, mat AF5$U8jf  
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    mat.Nd = nlens 9Vp|a&Ana  
    SetModelMaterial eID, mat p1B~:9y9X  
    Print "Set lens index of refraction = " & nlens E}U[VtaC  
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    '************************************************************************* B7"/K]dR:  
    'Pupil diameter ;lqtw]4v  
    '************************************************************************* = ;sEi:HC  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) :Mz$~o<  
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    'Adjust pupil diameter (trimming volume inner hole) U1?*vwfKZ  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" lWj|7  
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    ' Adjust pupil location to just in front of the lens r&AX  
    parID = FindFullName( "Geometry.Arizona Eye" ) 3e UTV<!  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) J 00<NRxj"  
    count = 0 N>z<v\`  
    While GetOperationCount(eID)>count v,t&t9}/  
        GetOperation eID, count, op !,}W|(P)  
        If op.Type="ShiftZ" Then [n/'JeG5  
            DeleteOperation eID,count 5IeF |#g  
            count=count-1 C`F*00M{  
        End If +hdD*}qauC  
        count=count+1 *hI  
    Wend ` aTkIo:ms  
    op.Type = "ShiftZ" C2GF N1i  
    op.val1 = taq-0.01 d4c-(ZRl  
    op.parent = parID jg8j>" Vj>  
    AddOperation eID, op uWw4l"RK`  
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    Print "Set pupil diameter = " & pupilDiam 9g3J{pKcZ  
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    'Update AZ Eye subassembly Description +RexQE  
    eID = FindFullName( "Geometry.Arizona Eye" ) fI"q/+  
    GetEntity eID, entity u}u;jTi> 2  
    entity.Description = "Accommodation = " & A & "D" ;Ab`b1B  
    SetEntity eID, entity '0_Z:\ laU  
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    Update 2kV[A92s  
    Print "DONE!" S -j<O&h~C  
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End Sub JlAUie8  
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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: @ mm*S:Gt#  
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Accommodation = 4 Diopters D$g|f[l  
Pupil Diameter = 4 mm UeB8|z  
Set aqueous humor thickness = 2.81 4HlOv % 8  
Set anterior lens radius = 10.4 and conic constant = -2.375869 b#0y-bR  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 sGIY\%  
Set lens thickness = 3.927 $3BCA)5:  
Set lens index of refraction = 1.42672 t ?8 ?Ok  
Set pupil diameter = 4 WjZJQK  
DONE! WrhC q6  
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