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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 :>=\.\  
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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。 ,N0#!<}4  
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模型 ? YG)I;(  
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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。 =AuR:Tx  
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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. rOVVL%@QqJ  
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光源 ,I,\ml  
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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!0-y  
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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。 yNbjoFM.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。 ~Rr~1I&mR,  
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图2. 字母F光源的设定方法光 tdu$pC6  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 %ALwz[~]  
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在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 r! MWbFw|X  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 \:UIc*S  
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图5. 视网膜重点采样规格设定
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脚本 .~7FyLl$  
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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: @nCd  
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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。 |mw.qI|  
余下的脚本计算与屈光度有关的所有参数。 4v{o  
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分析 e-EUf  
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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。 #*UN >X  
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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 SR |`!  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. LF& z  
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Dim entity As T_ENTITY ~ r4 38&  
Dim op As T_OPERATION .0`m\~L  
Dim mat As T_MODELMATERIAL 7V!*NBsl  
Dim A As Double S;286[oq@  
Dim pupilDiam As Double /^#;d UB  
Dim eID As Long YOmM=X+'H  
Dim parID As Long \6Zr  
Dim count As Integer 2OVRf0.R~  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double !`Hd-&}bYz  
Dim tlens As Double, nlens As Double GE%Z9#E  
Dim curv As Double, conic As Double S(*sw 0O@+  
Dim ok As Long =V-|#j  
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Sub Main M:[ %[+6  
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    '用户输入对话框 A#J`;5!Sc  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 @a0DT=>dT  
        TextBox 220,21,40,21,.TextBox1 'default: 0 q %"VYt4  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 dQA'($  
        OKButton 40,91,90,21 biU^[g("  
        CancelButton 190,91,90,21 l:,'j@%  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 6"J? #  
        TextBox 220,49,40,21,.TextBox2 'default: 4 @v)p<r^M">  
    End Dialog !C3MFm{B  
    Dim dlg As UserDialog wc}5m Hs  
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    ok = Dialog (dlg) TE7nJ gm  
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    If ok=0 Then    'cancel button was pressed 'm FqE n  
        Print "Execution cancelled." -~v2BN/  
        End e]$}-i@#  
    End If Tz8PSk1[  
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    'Assign accommodation and pupil diameter & use defaults if field left empty qzKdQ&vO  
    If dlg.TextBox1 = "" Then xqG[~)~  
        A = 0           'Default accommodation [ 0KlC1=  
    Else Gi?/C&1T  
        A = CDbl(dlg.TextBox1) K<SyC54  
    End If ,*&:2o_r  
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    If dlg.TextBox2 = "" Then |@ s,XS  
        pupilDiam = 4   'Default pupil diameter p93r'&Q  
    Else 6z#acE1)M  
        pupilDiam = CDbl(dlg.TextBox2) 8QLj["   
    End If Cz\e w B  
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    Print " " !sQY&*  
    Print "Accommodation = " & A & " Diopters" |Mu p8(gCk  
    Print "Pupil Diameter = " & pupilDiam & " mm" =hC,@R>;  
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    ' Calculate new parameters with accommodation bYpnt V  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ao1(]64X"  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens cdl&9-}  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens k;AD`7(=  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens -:Da&V  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens a eFe!`F  
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    tlens = 3.767 + 0.04*A                  'Lens thickness Lsq A**=  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction DS.RURzd{r  
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    'Adjust parameters to account for accommodation LrM=*R h,O  
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    '************************************************************************* "7'J &^|  
    'Aqueous thickness (Position of Lens) |[<_GQl  
    '************************************************************************* o{* e'4  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) BP'36?=Zo  
    GetCustomElement eID, entity %p^wZtm  
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    parID = FindFullName( "Geometry.Arizona Eye" ) 42_`+Vt]d7  
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    ' Delete any shift(s) in z tZ: _ag)o  
    count = 0 u]<,,  
    While GetOperationCount(eID)>count w28o}$b`  
        GetOperation eID, count, op z1PBMSG  
        If op.Type="ShiftZ" Then "CSsCA$/  
            DeleteOperation eID,count ddJQC|xR}  
            count=count-1 !;&p"E|b#  
        End If Zd^rNHhA  
        count=count+1 H[s(e5 6z  
    Wend ck ]Do!h  
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    'Set new shift in YSr9VpqWV  
    op.Type = "ShiftZ" [;4 g  
    op.val1 = taq .0S~872  
    op.parent = parID }iXDa?6%  
    AddOperation eID, op iV5yJF{ZH  
    Print "Set aqueous humor thickness = " & taq-0.55 b3&zjjQ  
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    '************************************************************************* ;(f) &Yom  
    'Radius and conic constant of anterior lens ,X[kt z  
    '************************************************************************* wa<MRt W=  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 9_# >aOqL  
    GetConic eID, entity, curv, conic rHC>z7+z.  
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    SetConic eID, entity, 1/Rant, CCant R0P iv:  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ~bM4[*Q7  
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    '************************************************************************* MW! srTQ_  
    'Radius and conic constant of posterior lens nHnK)9\N  
    '************************************************************************* NO7J!k?  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ]{)a,c NG  
    GetConic eID, entity, curv, conic 35Ij ..z0  
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    SetConic eID, entity, 1/Rpost, CCpost A_XY'z1  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 2KB\1&N  
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    '************************************************************************* K,Ef9c/+K  
    'Lens thickness (Position of posterior lens surface) 4^p5&5F  
    '************************************************************************* j#X.KM   
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6CV* Z\b  
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    ' Delete any z-shift(s) 6.CbAi3Z  
    count = 0 K#%&0D!  
    While GetOperationCount(eID)>count &v$rn#l  
        GetOperation eID, count, op `_BNy=`s*  
        If op.Type="ShiftZ" Then K{x\4  
            DeleteOperation eID,count X}=n:Ql'YY  
            count=count-1 @G BxL*e  
        End If -|J"s$yO4  
        count=count+1 m4TE5q%3  
    Wend ^WHE$4U`  
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    'Set new z-shift p31NIf `  
    op.Type = "ShiftZ" [=E  
    op.val1 = tlens x*![fK  
    op.parent = parID b=g8eMm  
    AddOperation eID, op _g+JA3sIJ  
    Print "Set lens thickness = " & tlens ta35 K"  
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    '************************************************************************* q+Lr"&'Q  
    'Lens index of refraction X>d"]GD  
    '************************************************************************* =+/eLKG  
    eID = FindMaterial( "Lens" ) 9*2[B"5  
    GetModelMaterial eID, mat VeGL)  
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    mat.Nd = nlens &qMPq->  
    SetModelMaterial eID, mat )jU)_To  
    Print "Set lens index of refraction = " & nlens nc~F_i=  
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    '************************************************************************* '[U8}z3  
    'Pupil diameter b1^vd@(lx  
    '************************************************************************* |2?'9<  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) NMW#AZVd  
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    'Adjust pupil diameter (trimming volume inner hole) iWei  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 1QqYQafA  
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    ' Adjust pupil location to just in front of the lens _p# CwExuy  
    parID = FindFullName( "Geometry.Arizona Eye" ) $56Z#'(D  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) /mXBvY  
    count = 0 1LqoF{S:  
    While GetOperationCount(eID)>count pM^9c7@!:  
        GetOperation eID, count, op )i~cr2Hk  
        If op.Type="ShiftZ" Then c|lu&}BS  
            DeleteOperation eID,count (hTCK8HK  
            count=count-1 +!k&Yje  
        End If nA?`BOe(  
        count=count+1 {kp-h2I,  
    Wend }XZ'v_Ti  
    op.Type = "ShiftZ" +J_c'ChN  
    op.val1 = taq-0.01 8;z6=.4xtg  
    op.parent = parID fXXr+Mor  
    AddOperation eID, op Tu@8}C  
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    Print "Set pupil diameter = " & pupilDiam - |kA)M[  
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    'Update AZ Eye subassembly Description `Y BC  
    eID = FindFullName( "Geometry.Arizona Eye" ) Wc,_RN-  
    GetEntity eID, entity W@T~ly;e*  
    entity.Description = "Accommodation = " & A & "D" F|F]970  
    SetEntity eID, entity cmBB[pk\  
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    Update 3j,Q`+l/6d  
    Print "DONE!" 0T@Zb={  
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End Sub flk=>h|  
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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: 7x#Ckep:I  
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Accommodation = 4 Diopters {xwm^p(f  
Pupil Diameter = 4 mm k xP-,MD  
Set aqueous humor thickness = 2.81 y@ ML/9X8q  
Set anterior lens radius = 10.4 and conic constant = -2.375869 %F\?R[^5  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 wkP#Z"A0~  
Set lens thickness = 3.927 6Ca(U'  
Set lens index of refraction = 1.42672 L/wD7/ODr  
Set pupil diameter = 4 =2Bg9!zW>  
DONE! F4It/  
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