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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 e(\I_  
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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。 iL?iz?+.%@  
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模型 6p<`h^  
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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。 2M6dMvS  
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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. H:oQ  
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光源 !Rw&DFU  
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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。 "G?9b  
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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。 K}x/ BhE+  
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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。 +l\<?  
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图2. 字母F光源的设定方法光 8 $ ~3ra  
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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 wGXwzU  
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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。 9m!7|(QV  
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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。 dB)9K)  
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图5. 视网膜重点采样规格设定
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脚本 ( pD7  
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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: {%7<"  
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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。 BJIQ zn3  
余下的脚本计算与屈光度有关的所有参数。 IK?]PmN4}  
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分析 3j&B(aLy  
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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。 j`9Nwa  
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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 SsRVd^=;x  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. eBvW#Hzp  
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Dim entity As T_ENTITY pzSqbgfrQ  
Dim op As T_OPERATION #Q+R%p  
Dim mat As T_MODELMATERIAL 0BXs&i-TP5  
Dim A As Double A\g%  
Dim pupilDiam As Double vzy!3Hiw  
Dim eID As Long F(0Z ]#+  
Dim parID As Long }} #be  
Dim count As Integer ^H'kHl'F  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double f !!P  
Dim tlens As Double, nlens As Double |D(&w+(  
Dim curv As Double, conic As Double "OJr*B  
Dim ok As Long `vX4! @Tw  
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Sub Main MLeX;He  
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    '用户输入对话框 x _|>n<Z  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 jMqx   
        TextBox 220,21,40,21,.TextBox1 'default: 0 /=ACdJ  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 1gk0l'.z  
        OKButton 40,91,90,21 fO+U HSC  
        CancelButton 190,91,90,21 U%,;N\:_  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 _Z.;u0Zp8  
        TextBox 220,49,40,21,.TextBox2 'default: 4 8>d q=0:  
    End Dialog z.j4tc9F/5  
    Dim dlg As UserDialog Un\Ubqi0  
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    ok = Dialog (dlg) Ff&R0v  
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    If ok=0 Then    'cancel button was pressed IadK@?X6j  
        Print "Execution cancelled." j`hNZ%a  
        End Z !Z,M' "  
    End If zM\IKo_"  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 5Abz 5-^KH  
    If dlg.TextBox1 = "" Then b_ZNI0Hp@  
        A = 0           'Default accommodation XK3!V|y`  
    Else ]'6'<S  
        A = CDbl(dlg.TextBox1) R @OSqEnr  
    End If A$N+9n\  
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    If dlg.TextBox2 = "" Then OMi02tSm  
        pupilDiam = 4   'Default pupil diameter LVoyA/ F  
    Else Pm;I3r=R\  
        pupilDiam = CDbl(dlg.TextBox2) hi0XVC95  
    End If 7\f{'KL  
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    Print " " p!QR3k.9s  
    Print "Accommodation = " & A & " Diopters" sl%#u9r=  
    Print "Pupil Diameter = " & pupilDiam & " mm" e$H|MdYIA  
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    ' Calculate new parameters with accommodation Mc!2mE%47m  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness V*>73I  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens yr%yy+(.k  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens qT"drgpi3  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 8B_0!U& ]  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens x<Iy<v7-  
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    tlens = 3.767 + 0.04*A                  'Lens thickness pmoGudaRF  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction h)7v1,;w'  
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    'Adjust parameters to account for accommodation \)p4okpR  
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    '************************************************************************* J1nXAh)J  
    'Aqueous thickness (Position of Lens) "k/;`eAP  
    '************************************************************************* GA(OK-WUd  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,n^TN{#  
    GetCustomElement eID, entity eSJAPU(D  
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    parID = FindFullName( "Geometry.Arizona Eye" ) =kwb` Z/a  
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    ' Delete any shift(s) in z qwL 0~I  
    count = 0 FK-}i|di  
    While GetOperationCount(eID)>count e',hC0&S  
        GetOperation eID, count, op =_K%$y*  
        If op.Type="ShiftZ" Then i<'{Y  
            DeleteOperation eID,count A>4l/  
            count=count-1 ,:c :6Y^  
        End If +[>y O _}  
        count=count+1 *Ro8W-+  
    Wend & 8ccrw  
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    'Set new shift in !&'# a  
    op.Type = "ShiftZ" FrgW7`s[A  
    op.val1 = taq }~myf\$  
    op.parent = parID q2[+-B)m  
    AddOperation eID, op un.G6|S  
    Print "Set aqueous humor thickness = " & taq-0.55 5wT' ,U"+  
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    '************************************************************************* Z'voCWCd  
    'Radius and conic constant of anterior lens ;%v%K+}r  
    '************************************************************************* Tbe_x s^  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) V;M3z9xd  
    GetConic eID, entity, curv, conic '~ jy  
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    SetConic eID, entity, 1/Rant, CCant 'hxs((['\  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Z}]:x `fXd  
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    '************************************************************************* HR/k{"8W4Q  
    'Radius and conic constant of posterior lens i)A`Vpn  
    '************************************************************************* R tXF  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) L-^# 02  
    GetConic eID, entity, curv, conic k/$Ja;  
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    SetConic eID, entity, 1/Rpost, CCpost "r5'lQI  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 4U}.Skzq  
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    '************************************************************************* m~Lf^gbG?  
    'Lens thickness (Position of posterior lens surface) daaga}]d  
    '************************************************************************* ek Y?  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Ws2prh^e(  
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    ' Delete any z-shift(s) T=hm#]   
    count = 0 &xPOp$Sx~  
    While GetOperationCount(eID)>count &6|6J1c8  
        GetOperation eID, count, op T{5M1r  
        If op.Type="ShiftZ" Then fY| @{]rx  
            DeleteOperation eID,count #o(?g-3  
            count=count-1 YHwVj?6W  
        End If VWnu#_(  
        count=count+1 avYh\xZ  
    Wend !?tu! M<1?  
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    'Set new z-shift z/ c'Z#w%  
    op.Type = "ShiftZ" {[(W4NAlH  
    op.val1 = tlens +lY\r +;  
    op.parent = parID %8bFQNd  
    AddOperation eID, op $6 Q2)^LJ  
    Print "Set lens thickness = " & tlens +iZ@.LI  
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    '************************************************************************* z9OMC$,V  
    'Lens index of refraction B=o#LL  
    '************************************************************************* UcKWa>:Fi  
    eID = FindMaterial( "Lens" ) ;iwD/=Y  
    GetModelMaterial eID, mat W#oEF/G  
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    mat.Nd = nlens f4@#pnJ3po  
    SetModelMaterial eID, mat ;n:H6cp  
    Print "Set lens index of refraction = " & nlens #=)?s 8T  
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    '************************************************************************* Z(Ls#hp  
    'Pupil diameter N@%xLJF=N>  
    '************************************************************************* DcFV^8O&  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *`\4j*$^  
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    'Adjust pupil diameter (trimming volume inner hole) !'6J;Fb#  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" V.E.~<7D\  
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    ' Adjust pupil location to just in front of the lens D%5 {A=  
    parID = FindFullName( "Geometry.Arizona Eye" ) q(${jz4w  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) [8om9 Z3  
    count = 0 0zq\ j  
    While GetOperationCount(eID)>count "~ i#9L/H  
        GetOperation eID, count, op SbQ{ >  
        If op.Type="ShiftZ" Then v~W6yjp  
            DeleteOperation eID,count fu7[8R"{  
            count=count-1 ":ws~Zep  
        End If :jN;l  
        count=count+1 HjE Tinm"  
    Wend  # 8-P  
    op.Type = "ShiftZ" Q%b46"  
    op.val1 = taq-0.01 CsQ}P)  
    op.parent = parID '&o> %V  
    AddOperation eID, op u.xA}yVS  
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    Print "Set pupil diameter = " & pupilDiam %CfTqbB  
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    'Update AZ Eye subassembly Description R.n`R|NOd  
    eID = FindFullName( "Geometry.Arizona Eye" ) aX%g+6t2  
    GetEntity eID, entity rqG6Ll`=+  
    entity.Description = "Accommodation = " & A & "D" )I0g&e^Tzy  
    SetEntity eID, entity s#8{:ko  
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    Update <P Z\qE*+y  
    Print "DONE!" &<; nl^  
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End Sub h?O%XnD  
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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: =K&q;;h  
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Accommodation = 4 Diopters hJtghG6v  
Pupil Diameter = 4 mm jind!@}!  
Set aqueous humor thickness = 2.81 v(WL 3[y;  
Set anterior lens radius = 10.4 and conic constant = -2.375869 Y_ u7 0@`  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 l>Oe ,`9O  
Set lens thickness = 3.927 :O2v0Kx  
Set lens index of refraction = 1.42672 xdSj+507  
Set pupil diameter = 4 @%okaj#IO  
DONE! [E&"9%K  
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