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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。 X3X_=qzc  
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模型 Jt@lH  
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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。 2_+>a"8Y  
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. -` U |5  
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光源 e12QYoh  
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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。 =I@t%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。 ?<TJ}("/  
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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。 E,}{iqAb  
图2. 字母F光源的设定方法光 _9 ]:0bDUo  
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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 Cp6S2v I  
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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。 |Ev|A9J!  
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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。 ;7QXs39S  
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图5. 视网膜重点采样规格设定
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脚本 j|k/&q[St  
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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: oAQQ OtpZN  
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。 olE(#}7V  
余下的脚本计算与屈光度有关的所有参数。 7__[=)(b2X  
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分析 )S g6B;CJ  
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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。 hv|a8=U!R  
图7. 字母F在视网膜上颜色分析
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脚本代码 @:C)^f"  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. eU1F7LS  
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Dim entity As T_ENTITY nK1eh@a9Qv  
Dim op As T_OPERATION TTz=*t+D  
Dim mat As T_MODELMATERIAL S hI1f  
Dim A As Double tYu<(Z(l)  
Dim pupilDiam As Double k$3pmy*  
Dim eID As Long Kjd3!%4mB  
Dim parID As Long x77L"5g  
Dim count As Integer !kovrvM6F  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double >G6kF!V  
Dim tlens As Double, nlens As Double wk|+[Rl;L  
Dim curv As Double, conic As Double J:@gmo`M;V  
Dim ok As Long ^wIB;!W  
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Sub Main 4z0gyCAC A  
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    '用户输入对话框 \f9WpAY  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 FS1\`#Bm)  
        TextBox 220,21,40,21,.TextBox1 'default: 0 v`A)GnNiN  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 7;EDU  
        OKButton 40,91,90,21 (U:-z=E#1  
        CancelButton 190,91,90,21 }dkXRce*  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 q<&1,^ A  
        TextBox 220,49,40,21,.TextBox2 'default: 4 u cpU $+  
    End Dialog J!uG/ Us  
    Dim dlg As UserDialog d&+]@ Ii  
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    ok = Dialog (dlg) f24W*#IX  
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    If ok=0 Then    'cancel button was pressed 1K Fd ~U  
        Print "Execution cancelled." xMjhC;i{  
        End Ib..X&N2  
    End If A9xe Oy8e  
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    'Assign accommodation and pupil diameter & use defaults if field left empty qp})4XTv  
    If dlg.TextBox1 = "" Then \CjJa(vV  
        A = 0           'Default accommodation v"k ? e  
    Else pP| @Z{7d`  
        A = CDbl(dlg.TextBox1) R-Edht|{  
    End If w6vbYPCN  
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    If dlg.TextBox2 = "" Then *tqD:hiF  
        pupilDiam = 4   'Default pupil diameter rCPIz<  
    Else qO>UN[Y  
        pupilDiam = CDbl(dlg.TextBox2) wn[)/*(,$(  
    End If :nIMZRJ_!E  
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    Print " " a=MN:s?Fc0  
    Print "Accommodation = " & A & " Diopters" KhR3$|fH<  
    Print "Pupil Diameter = " & pupilDiam & " mm" vb>F)X?b_  
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    ' Calculate new parameters with accommodation F$t]JM  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness )g@+ MR  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens f;'*((  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 5M5Bm[X  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens z*},N$2=  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ~@'wqGTp  
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    tlens = 3.767 + 0.04*A                  'Lens thickness $Tbsre\MJ  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction KU8,8:yY  
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    'Adjust parameters to account for accommodation &wQ;J)13  
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    '************************************************************************* rUKg<]&@  
    'Aqueous thickness (Position of Lens) |+Wn5iT  
    '************************************************************************* HYdM1s6vo  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) V(`]hH0;T  
    GetCustomElement eID, entity l#[Z$+!09  
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    parID = FindFullName( "Geometry.Arizona Eye" ) XUP{]w`.Z  
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    ' Delete any shift(s) in z m"!SyN}&9?  
    count = 0 $@Vn+| Ix  
    While GetOperationCount(eID)>count V|YQhd0kv  
        GetOperation eID, count, op R'gd/.[e  
        If op.Type="ShiftZ" Then EDnNS  
            DeleteOperation eID,count Au2?f~#Fv  
            count=count-1 5UQ {qm*Q  
        End If mu\1hKq;B  
        count=count+1 Z1fY' f  
    Wend V*n$$-5 1-  
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    'Set new shift in ~xqiasE#K  
    op.Type = "ShiftZ" T";evM66  
    op.val1 = taq /si<Fp)z  
    op.parent = parID B?B OAH  
    AddOperation eID, op s*rR> D:  
    Print "Set aqueous humor thickness = " & taq-0.55 3jZGO9ttnS  
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    '************************************************************************* 6k hBT'n  
    'Radius and conic constant of anterior lens ]T)N{"&N/  
    '************************************************************************* y,:WLk~  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) LuySa2 ,  
    GetConic eID, entity, curv, conic =d Q[I6  
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    SetConic eID, entity, 1/Rant, CCant 0`E G-Hw  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant _*H Hdd5I  
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    '************************************************************************* LAC&W;pJ"  
    'Radius and conic constant of posterior lens eWFkUjz  
    '************************************************************************* ,yC..aI  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) xn`)I>v  
    GetConic eID, entity, curv, conic n$2oM5<  
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    SetConic eID, entity, 1/Rpost, CCpost O7 ;=g!j  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost NFTv4$5d  
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    '************************************************************************* Q\4tzb]  
    'Lens thickness (Position of posterior lens surface) K9zr]7;th  
    '************************************************************************* zr!7*, p  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) X$UK;O  
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    ' Delete any z-shift(s) )p>Cf_[.  
    count = 0  0J+WCm`  
    While GetOperationCount(eID)>count CcUF)$kz  
        GetOperation eID, count, op kn}^oRT  
        If op.Type="ShiftZ" Then %%K3J<5  
            DeleteOperation eID,count zg ,=A?  
            count=count-1 *IOrv)  
        End If MiZ<v/L2  
        count=count+1 6CFnE7TQf  
    Wend  _".h(  
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    'Set new z-shift 8=$XhC  
    op.Type = "ShiftZ" Z7bJ<TpZ  
    op.val1 = tlens n{N0S^h  
    op.parent = parID sgO au\E  
    AddOperation eID, op T'}kCnp  
    Print "Set lens thickness = " & tlens ~R[ k^i.Y  
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    '************************************************************************* x_~_/&X5  
    'Lens index of refraction IM1&g7Qs2  
    '************************************************************************* $,K@xq5  
    eID = FindMaterial( "Lens" ) (eF[nfM  
    GetModelMaterial eID, mat )Lz =[e  
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    mat.Nd = nlens f_)#  
    SetModelMaterial eID, mat by+xK~>  
    Print "Set lens index of refraction = " & nlens *f 7rLM*  
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    '************************************************************************* sg=G<50i  
    'Pupil diameter |yz[mP*;o  
    '************************************************************************* [;{xiW4V]  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ftpPrtaP  
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    'Adjust pupil diameter (trimming volume inner hole) kxKb}> =  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" NxF:s,a6  
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    ' Adjust pupil location to just in front of the lens .u\$wJ9Ai  
    parID = FindFullName( "Geometry.Arizona Eye" ) k6"(\d9o  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) LCSvw  
    count = 0 ]*P9=!x|M  
    While GetOperationCount(eID)>count vLxaZWr  
        GetOperation eID, count, op hdWVvN  
        If op.Type="ShiftZ" Then ]2l}[ w71|  
            DeleteOperation eID,count l7uTk5  
            count=count-1 Tv1oy%dK  
        End If gs!'*U)  
        count=count+1 i#4+l$q  
    Wend T%oJmp?0  
    op.Type = "ShiftZ" +%j27~ R>D  
    op.val1 = taq-0.01 AmC9qk8Q  
    op.parent = parID `Kg!aN  
    AddOperation eID, op ~ S<aIk0l  
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    Print "Set pupil diameter = " & pupilDiam }'tJc $!  
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    'Update AZ Eye subassembly Description ]&H"EHC<$  
    eID = FindFullName( "Geometry.Arizona Eye" ) Z$INmo6  
    GetEntity eID, entity #w%-IhP  
    entity.Description = "Accommodation = " & A & "D" KDb j C'3  
    SetEntity eID, entity hBRi5&%  
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    Update tl /i  
    Print "DONE!" OvQzMXU^I  
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End Sub [K,P)V>K  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: kJl^,q  
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Accommodation = 4 Diopters ,\iXZ5"R  
Pupil Diameter = 4 mm UUDHknm"  
Set aqueous humor thickness = 2.81 C{$iuus0  
Set anterior lens radius = 10.4 and conic constant = -2.375869 K" VcPDK  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 } r(b:}DN  
Set lens thickness = 3.927 6)0.q|Q  
Set lens index of refraction = 1.42672 c_ncx|dUs  
Set pupil diameter = 4 d)V8FX,t  
DONE!
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