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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 |0w~P s  
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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。 WB;J1TpM7  
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模型 }9}w8R~E  
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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。 1}DerX6  
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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. g^n;IE$B  
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光源 /C7svH  
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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。 |0DP} `~  
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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。 y3AL)  
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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。 o@@_J@}#  
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图2. 字母F光源的设定方法光 Yoe les-  
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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 m^Rd Iy)  
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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。 & ]%\.m  
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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。 {;;eOxOP|  
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图5. 视网膜重点采样规格设定
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脚本 L&rO  6  
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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: QZ:v  
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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。 XZ; *>(  
余下的脚本计算与屈光度有关的所有参数。 ]&/0  
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分析 7kOE/>P?  
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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。 y K=S!7p\  
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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 pEJ#ad  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. PlF89-  
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Dim entity As T_ENTITY +q$xw}+PK  
Dim op As T_OPERATION HarYV :  
Dim mat As T_MODELMATERIAL B?!9W@  
Dim A As Double <tGI]@Nwk  
Dim pupilDiam As Double p`pg5R  
Dim eID As Long J,.j_ii`!  
Dim parID As Long N,h1$)\B#  
Dim count As Integer Dg1kbO=2  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double i#Ne'q;T  
Dim tlens As Double, nlens As Double 5F% h>tqh  
Dim curv As Double, conic As Double z0=Rp0_W  
Dim ok As Long J~M H_N  
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Sub Main X!7 c zt  
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    '用户输入对话框 XPGL3[w\V  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 F]/L!   
        TextBox 220,21,40,21,.TextBox1 'default: 0 -ryDsq  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 5@GD} oAn6  
        OKButton 40,91,90,21 &Bj,.dD/a  
        CancelButton 190,91,90,21 ppPG+[cz  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 pE$|2v  
        TextBox 220,49,40,21,.TextBox2 'default: 4 VyB\]EBu  
    End Dialog -[i40 1  
    Dim dlg As UserDialog ey'pm\Z  
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    ok = Dialog (dlg) T b5$  
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    If ok=0 Then    'cancel button was pressed -lJx%9>  
        Print "Execution cancelled." $]Q*E4(kV9  
        End @&!=m]D*  
    End If e|2vb GQ  
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    'Assign accommodation and pupil diameter & use defaults if field left empty o|zrD~&$  
    If dlg.TextBox1 = "" Then $.suu^>^w  
        A = 0           'Default accommodation ] P:NnKgK  
    Else 8MYLXW6  
        A = CDbl(dlg.TextBox1) ^&f{beU9  
    End If h(+m<J  
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    If dlg.TextBox2 = "" Then Q#yu(  
        pupilDiam = 4   'Default pupil diameter &hSnB~hi  
    Else {ar5c&<  
        pupilDiam = CDbl(dlg.TextBox2) CF4Oh-f  
    End If tEpIyC  
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    Print " " =8$(i[;6w  
    Print "Accommodation = " & A & " Diopters" | o;j0  
    Print "Pupil Diameter = " & pupilDiam & " mm" L@gQ L  
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    ' Calculate new parameters with accommodation e]dPF[?7  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness P;HVLflu  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens i/C -{+}U  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens PMz{8 F  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ZTgAZ5_cz  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens $ DABR  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 0x3 h8fs  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction ,Do$`yO+  
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    'Adjust parameters to account for accommodation `[C  v-  
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    '************************************************************************* m-Z'K_oQ  
    'Aqueous thickness (Position of Lens) +7lRP)1R  
    '************************************************************************* .Y^d9.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) qJbhPY8Ak  
    GetCustomElement eID, entity @Le ^-v4  
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    parID = FindFullName( "Geometry.Arizona Eye" ) -Z/6;2Q  
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    ' Delete any shift(s) in z [#,X$O>  
    count = 0 Gct&}]3pm  
    While GetOperationCount(eID)>count X,iuz/Q  
        GetOperation eID, count, op j"D0nG,  
        If op.Type="ShiftZ" Then R.T?ZF  
            DeleteOperation eID,count )LMBxyS  
            count=count-1 n8;G,[GM80  
        End If )=,9`+Zta  
        count=count+1 Gg3?2h"d  
    Wend &Gy'AUz-  
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    'Set new shift in x jP" 'yU  
    op.Type = "ShiftZ" ,,C~j`F  
    op.val1 = taq 0%&fUz36E6  
    op.parent = parID SCI-jf3WN  
    AddOperation eID, op S7#^u`'Q_^  
    Print "Set aqueous humor thickness = " & taq-0.55 x=)30y3*;  
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    '************************************************************************* dZ]\1""#H  
    'Radius and conic constant of anterior lens kw-Kx4 )  
    '************************************************************************* v#<+n{B  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) WO \lny!  
    GetConic eID, entity, curv, conic v%l|S{>(  
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    SetConic eID, entity, 1/Rant, CCant L2/<+ Zw  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant pn_gq~5ng  
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    '************************************************************************* |V~(mS747:  
    'Radius and conic constant of posterior lens zOdasEd8!  
    '************************************************************************* )*$  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) (J,Oh  
    GetConic eID, entity, curv, conic Z+"E*  
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    SetConic eID, entity, 1/Rpost, CCpost ]a%\Q 2[c  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost N:gstp  
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    '*************************************************************************  JY050FL  
    'Lens thickness (Position of posterior lens surface) $nD k mKl  
    '************************************************************************* )>#<S0>'j  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) enD C#  
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    ' Delete any z-shift(s) ][$$  =  
    count = 0 `v/tf|v 6  
    While GetOperationCount(eID)>count EBn:[2  
        GetOperation eID, count, op E/ed0'|m  
        If op.Type="ShiftZ" Then *!7SM 7  
            DeleteOperation eID,count uwS'*5tU  
            count=count-1 j"$b%|  
        End If |#k hwH  
        count=count+1 2Nt]Nj`  
    Wend @}rfY9o'  
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    'Set new z-shift $lG--s  
    op.Type = "ShiftZ" *.;}OX^X  
    op.val1 = tlens "F.J>QBd  
    op.parent = parID J`D<  
    AddOperation eID, op TXk"[>,:H  
    Print "Set lens thickness = " & tlens fS$Yl~-m?  
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    '************************************************************************* 8'_ ]gfF  
    'Lens index of refraction /7HIL?r  
    '************************************************************************* r@V(w`  
    eID = FindMaterial( "Lens" ) [?r\b  
    GetModelMaterial eID, mat 8#JyK+NU  
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    mat.Nd = nlens -3XnK5  
    SetModelMaterial eID, mat WaO;hy~us  
    Print "Set lens index of refraction = " & nlens %^@0tT  
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    '************************************************************************* H(ftOd.y  
    'Pupil diameter 58gt*yVu  
    '************************************************************************* ~s ja^  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) [(^''*7r+T  
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    'Adjust pupil diameter (trimming volume inner hole) W;x LuKIG  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Hn2Q1lF-ip  
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    ' Adjust pupil location to just in front of the lens I3=Sc^zz&V  
    parID = FindFullName( "Geometry.Arizona Eye" ) gRd1(S  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) XXdMppoR  
    count = 0 hdDI%3vk3  
    While GetOperationCount(eID)>count I)4|?tb ?  
        GetOperation eID, count, op "%iR-s_>  
        If op.Type="ShiftZ" Then \Hx#p`B%  
            DeleteOperation eID,count ,T>2zSk  
            count=count-1 ~CTRPH   
        End If 5UD;Z V%  
        count=count+1 "Q!{8 9Y  
    Wend ^Q+5M"/8  
    op.Type = "ShiftZ" Y7I  
    op.val1 = taq-0.01 Yy;1N{dbT  
    op.parent = parID C2%3+  
    AddOperation eID, op 6B P%&RL  
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    Print "Set pupil diameter = " & pupilDiam 7`n8 OR4  
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    'Update AZ Eye subassembly Description IZ ha* 7  
    eID = FindFullName( "Geometry.Arizona Eye" ) wA+4:CF @  
    GetEntity eID, entity k5<0M'  
    entity.Description = "Accommodation = " & A & "D" gM]/Y6 *$b  
    SetEntity eID, entity 3JO:n6  
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    Update 5 `mVe0uI  
    Print "DONE!" HUX+d4sg  
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End Sub ( I~XwP&  
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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: 4p g(QeR  
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Accommodation = 4 Diopters c=mFYsSv  
Pupil Diameter = 4 mm C /VXyl@o  
Set aqueous humor thickness = 2.81 vx,6::%]  
Set anterior lens radius = 10.4 and conic constant = -2.375869 \3UdC{~  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 c'4 \F9  
Set lens thickness = 3.927 NWcF9z%@  
Set lens index of refraction = 1.42672 rV{e[fGd  
Set pupil diameter = 4 2Nszxvq,  
DONE! z>q_]U0  
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