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infotek 2023-04-27 08:29

Arizona眼睛模型

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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。 Y7;=\/SV  
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模型 T[MDjhv'  
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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。 p!DOc8a.\e  
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. \"w+4}  
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光源 2w fkXS=~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。 tJmy}.t1  
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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。 Lcf?VV}  
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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。 {a15s6'd  
图2. 字母F光源的设定方法光 Y*IKPnPot2  
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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 (p] S  
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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。 umCmxm r&  
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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。 YFW/ Fa\7  
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图5. 视网膜重点采样规格设定
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脚本 ^E.mG>  
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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: lCTXl5J5  
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。 uGHM ]"!)  
余下的脚本计算与屈光度有关的所有参数。 yXqC  
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分析 <PM.4B@  
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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。 ?*ZQ:jH  
图7. 字母F在视网膜上颜色分析
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脚本代码 V]m}xZ'?^  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. ,_s.amL3O{  
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Dim entity As T_ENTITY _!Pi+l4p/}  
Dim op As T_OPERATION J8ScKMUN2  
Dim mat As T_MODELMATERIAL Cl3L)  
Dim A As Double t=|}?lN<  
Dim pupilDiam As Double _~*j=XRs  
Dim eID As Long 72_+ b  
Dim parID As Long ydj*Jy'  
Dim count As Integer 5NhAb$q2Y  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double W39J)~D^@  
Dim tlens As Double, nlens As Double s,AJR [  
Dim curv As Double, conic As Double _+H $Pa}?  
Dim ok As Long f6nuh&!-  
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Sub Main X*w;6 V  
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    '用户输入对话框 NeP  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 4'`H H  
        TextBox 220,21,40,21,.TextBox1 'default: 0 E9Dy)f]#W  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 E1dhj3+3  
        OKButton 40,91,90,21 9W_mSum  
        CancelButton 190,91,90,21 PgHmOs  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 7=Pj}x)  
        TextBox 220,49,40,21,.TextBox2 'default: 4 BUV4L5(  
    End Dialog {d]B+'  
    Dim dlg As UserDialog 2oOos%0  
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    ok = Dialog (dlg) c5:0`~5Fn  
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    If ok=0 Then    'cancel button was pressed 33wVP}e5  
        Print "Execution cancelled." fY?:SPR+  
        End 2(Yg',aMY-  
    End If &4 #%xg  
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    'Assign accommodation and pupil diameter & use defaults if field left empty TTbJ9O<43  
    If dlg.TextBox1 = "" Then dw!Xt@,[g{  
        A = 0           'Default accommodation i )$+#N  
    Else 5e1oxSU  
        A = CDbl(dlg.TextBox1) [*I7^h%  
    End If jTZi< Y:bB  
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    If dlg.TextBox2 = "" Then a/H5Y,b>  
        pupilDiam = 4   'Default pupil diameter 5wE6gRJ  
    Else J><hrZ  
        pupilDiam = CDbl(dlg.TextBox2) fe"w--v  
    End If Da!vGr  
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    Print " " B1s&2{L6K  
    Print "Accommodation = " & A & " Diopters" %e)vl[:}  
    Print "Pupil Diameter = " & pupilDiam & " mm" >Q^ mR  
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    ' Calculate new parameters with accommodation !0|&f>y  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness L; A#N9  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens z4` :n.  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens g\?07@Zd|  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Eza^Tbq%j?  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ;-l^X%r  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 0(9gTxdB  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction e=IbEm{|  
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    'Adjust parameters to account for accommodation ,KF>@3f  
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    '************************************************************************* ZCb@!V}=  
    'Aqueous thickness (Position of Lens) zQt)>Qx_  
    '************************************************************************* 7}~nQl2  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) mo= @Zt  
    GetCustomElement eID, entity ,?Vxcr  
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    parID = FindFullName( "Geometry.Arizona Eye" ) dS \n 2Qb  
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    ' Delete any shift(s) in z .i*ja*   
    count = 0 ";jAHGbO  
    While GetOperationCount(eID)>count V~5vR`}  
        GetOperation eID, count, op 7~ZG"^k  
        If op.Type="ShiftZ" Then m7XN6zX  
            DeleteOperation eID,count jGJf[:M&Pm  
            count=count-1 /X#OX 8gb]  
        End If RU=g|TL  
        count=count+1 EG8z&^O x  
    Wend ;ByCtVm2  
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    'Set new shift in e%{7CR'~TD  
    op.Type = "ShiftZ" P9Eh, j0_  
    op.val1 = taq {_z6  
    op.parent = parID '-G,7!.,r%  
    AddOperation eID, op i12G\Ye  
    Print "Set aqueous humor thickness = " & taq-0.55 -GQ.B{%G  
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    '************************************************************************* 4"{g{8  
    'Radius and conic constant of anterior lens 2"P1I  
    '************************************************************************* R iV]SgV 9  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 73tjDO7d  
    GetConic eID, entity, curv, conic @cm[]]f'l  
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    SetConic eID, entity, 1/Rant, CCant Qt^6w}&  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant w> Ft5"z  
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    '************************************************************************* !4t%\N6Ib  
    'Radius and conic constant of posterior lens `$3P@SO"  
    '************************************************************************* AP=SCq;  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 09G]t1!,  
    GetConic eID, entity, curv, conic Z vyF"4QN  
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    SetConic eID, entity, 1/Rpost, CCpost I9U 8@e!X  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost dPgA~~  
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    '************************************************************************* HDu|KW$o1  
    'Lens thickness (Position of posterior lens surface) lb"T'} q  
    '************************************************************************* .Dr7YquW  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ~IQjQz?  
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    ' Delete any z-shift(s) :b#5 cMUe  
    count = 0 aIWpgUd`  
    While GetOperationCount(eID)>count l?;ReK.r  
        GetOperation eID, count, op :n x;~f  
        If op.Type="ShiftZ" Then nXxnyom,  
            DeleteOperation eID,count U2JxzHXZ  
            count=count-1 "DJ%Yo  
        End If J=n^&y  
        count=count+1 T16B2|C"Y  
    Wend xrJ0  
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    'Set new z-shift h 'is#X 6:  
    op.Type = "ShiftZ" O9p^P%U"  
    op.val1 = tlens lPlJL`e  
    op.parent = parID Mq6_Q07  
    AddOperation eID, op i'#%t/ u  
    Print "Set lens thickness = " & tlens x6=tS  
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    '************************************************************************* %g4)f9>  
    'Lens index of refraction 6|%HCxWO  
    '************************************************************************* fK=vLcH  
    eID = FindMaterial( "Lens" ) $>%zNq-F  
    GetModelMaterial eID, mat |e3YTLsI  
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    mat.Nd = nlens HsK5 2<  
    SetModelMaterial eID, mat / pR,l5  
    Print "Set lens index of refraction = " & nlens 9x9E+DG#(  
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    '************************************************************************* %,)Xi  
    'Pupil diameter I]ol[ X0S  
    '************************************************************************* xtp55"g  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) UX'tdB !A  
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    'Adjust pupil diameter (trimming volume inner hole) 'wTJX>  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" a.AEF P4N  
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    ' Adjust pupil location to just in front of the lens KhbbGdmfS$  
    parID = FindFullName( "Geometry.Arizona Eye" ) zPb "6%1B  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) v8A{ q  
    count = 0 #Cz:l|\ i  
    While GetOperationCount(eID)>count 2{#=Ygb0  
        GetOperation eID, count, op hM`*- +Zb  
        If op.Type="ShiftZ" Then t]pJt  
            DeleteOperation eID,count .ZH5^Sv$vp  
            count=count-1 mHC36ba  
        End If \Ng[lN  
        count=count+1 %w6lNl  
    Wend DZ|/#- k  
    op.Type = "ShiftZ" k8"[)lDc.  
    op.val1 = taq-0.01 o/\z4Ri)$  
    op.parent = parID ~bJ*LM?wOP  
    AddOperation eID, op YA^g[,  
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    Print "Set pupil diameter = " & pupilDiam 22m'+3I~Y  
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    'Update AZ Eye subassembly Description \[x4  
    eID = FindFullName( "Geometry.Arizona Eye" ) :~9F/Jx  
    GetEntity eID, entity & |o V\L  
    entity.Description = "Accommodation = " & A & "D" [ x|{VJ(h  
    SetEntity eID, entity 93#wU})  
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    Update h%@#jvh?4  
    Print "DONE!" V?cUQghHg  
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End Sub aA.TlG@zP  
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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: L"!BN/i_  
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Accommodation = 4 Diopters "A9 c]  
Pupil Diameter = 4 mm .c.#V:XZ#U  
Set aqueous humor thickness = 2.81 x; *KRO  
Set anterior lens radius = 10.4 and conic constant = -2.375869 _u`W$EG L  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 PK* $  
Set lens thickness = 3.927 D<cHa |  
Set lens index of refraction = 1.42672 I^6zUVH  
Set pupil diameter = 4 Bhrp"l +|  
DONE!
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