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xunjigd 2016-02-24 12:53

FRED运用：Arizona眼睛模型

简介 hLJO\=0rJz  
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。 O`rrg~6#  
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模型 #N,\c@Gy  
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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。 =XudL^GF  
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Table 1. AZ眼睛模型的定义
[attachment=67931]
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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. .DCp)&m l;  
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光源 }2DeqY  
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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。 6 U# C  
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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。 I>G)wRpfR'  
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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。 ]FQ4v.7  
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图2. 字母F光源的设定方法光 Cg)#B+  
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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 {TUCa  
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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。 c S{l2}E  
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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。 [o|]>(tk  
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[attachment=67936]
图5. 视网膜重点采样规格设定
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脚本 |!IJ/ivEgw  
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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： ;|9VPv/  
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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。 tk_y~-xz  
余下的脚本计算与屈光度有关的所有参数。 <2|x]b 8  
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分析 vR+(7^Yy  
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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。 Hk3HzN 3  
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[attachment=67939]
图7. 字母F在视网膜上颜色分析
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脚本代码 :gQc@)jZ(*  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. NW!e@;E+i  
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Dim entity As T_ENTITY <|.S~HLTQ  
Dim op As T_OPERATION AO^F6Y/  
Dim mat As T_MODELMATERIAL X3 a:*1N  
Dim A As Double oqE h_[.  
Dim pupilDiam As Double `.[hOQ7  
Dim eID As Long )t)tk=R9N  
Dim parID As Long MZL~IX  
Dim count As Integer h3O5DP6~  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double QHtpCNTVb  
Dim tlens As Double, nlens As Double n=hz7tjaz  
Dim curv As Double, conic As Double <<n8P5pXt  
Dim ok As Long >@]E1Qfe  
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Sub Main S :(1=@  
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    '用户输入对话框 _);1dcnR  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 |fRajuA;  
        TextBox 220,21,40,21,.TextBox1 'default: 0 5]'iSrp  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 y fP&Q<|  
        OKButton 40,91,90,21 '7_'s1  
        CancelButton 190,91,90,21 `bt]v$  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Or6'5e?N  
        TextBox 220,49,40,21,.TextBox2 'default: 4 }14.u&4  
    End Dialog q{KRM\ooYs  
    Dim dlg As UserDialog fI"`[cA"]  
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    ok = Dialog (dlg) <_42h|-  
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    If ok=0 Then    'cancel button was pressed r2U2pAy#  
        Print "Execution cancelled." mP:mzmUw  
        End 94K ;=5h  
    End If eb( =V *  
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    'Assign accommodation and pupil diameter & use defaults if field left empty Uv%"45&7  
    If dlg.TextBox1 = "" Then CsuSg*#X+  
        A = 0           'Default accommodation KZD&Ih(vC  
    Else M5P63=1+  
        A = CDbl(dlg.TextBox1) &dOV0y_  
    End If X}p4yR7'  
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    If dlg.TextBox2 = "" Then `o:)PTQNg  
        pupilDiam = 4   'Default pupil diameter z|pH>R?:  
    Else ]=]'*Z%  
        pupilDiam = CDbl(dlg.TextBox2) 0*tEuJ7  
    End If ~r>WnI:vg  
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    Print " " 4H\O&pSS  
    Print "Accommodation = " & A & " Diopters" u# %7>=  
    Print "Pupil Diameter = " & pupilDiam & " mm" xnh%nv<v{  
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    ' Calculate new parameters with accommodation SkPv.H0Id  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness QP\vN|r  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 8mCr6$|%  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Tri.>@-u  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ]JhtO{  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens U*6-Y%7  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 4)XN1r:  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction LO` (V  
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    'Adjust parameters to account for accommodation ytAhhwN~  
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    '************************************************************************* qqkZbsN  
    'Aqueous thickness (Position of Lens) d628@~ Ekn  
    '************************************************************************* R[_7ab]A  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) oh:t ex<  
    GetCustomElement eID, entity xRaYm  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ]v9<^!  
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    ' Delete any shift(s) in z MhJ`>.z1  
    count = 0 ,'ndQ{\9  
    While GetOperationCount(eID)>count N%Lh_2EzqV  
        GetOperation eID, count, op Y-,#3%bT;;  
        If op.Type="ShiftZ" Then FE_n+^|k<  
            DeleteOperation eID,count `qfVgT=2  
            count=count-1 VvoJ85  
        End If 6\E |`  
        count=count+1 G`)I _uO  
    Wend 4vy!'r@   
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    'Set new shift in Qs,LK(1  
    op.Type = "ShiftZ" ~&KfJ  
    op.val1 = taq L8ZCGW\Rr  
    op.parent = parID 3mBr nq]j>  
    AddOperation eID, op lhxhAe  
    Print "Set aqueous humor thickness = " & taq-0.55 {8UBxFIM(  
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    '************************************************************************* !(o)*S  
    'Radius and conic constant of anterior lens Ay2|@1e  
    '************************************************************************* H5qa7JMZ  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) f|b|\/.=  
    GetConic eID, entity, curv, conic Ke\?;1+  
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    SetConic eID, entity, 1/Rant, CCant c[j3_fn1]  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant dXdU4YJ X  
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    '************************************************************************* ]cA){^.Jz  
    'Radius and conic constant of posterior lens b"f4}b  
    '************************************************************************* Yq2 mVo  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) <89 js87  
    GetConic eID, entity, curv, conic R)<>} y  
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    SetConic eID, entity, 1/Rpost, CCpost kmP0gT{Sj  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost >j$f$*x  
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    '************************************************************************* %GHHnf%2Z  
    'Lens thickness (Position of posterior lens surface) 4q~l ?*S  
    '************************************************************************* 55yP.@i9J  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" )  [bv.`  
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    ' Delete any z-shift(s) xorFz{  
    count = 0 ;f6G&>p  
    While GetOperationCount(eID)>count q Rtgk  
        GetOperation eID, count, op -@i2]o  
        If op.Type="ShiftZ" Then #xts*{u-#  
            DeleteOperation eID,count w0 "h,{  
            count=count-1 ?EYF61? rw  
        End If mX"z$  
        count=count+1 (]iw#m{  
    Wend wN*e6dOF  
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    'Set new z-shift 5V%K'a(  
    op.Type = "ShiftZ" rl6vt*g  
    op.val1 = tlens  snN1  
    op.parent = parID /'">H-r  
    AddOperation eID, op GR|Vwxs<@P  
    Print "Set lens thickness = " & tlens B4J^ rzK  
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    '************************************************************************* Q}]Q0'X8  
    'Lens index of refraction Q&n|tQ*4  
    '************************************************************************* fV;&Ag*ZiV  
    eID = FindMaterial( "Lens" ) q>H!?zi\Hy  
    GetModelMaterial eID, mat N|Rlb5\  
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    mat.Nd = nlens Y`c\{&M6  
    SetModelMaterial eID, mat %PyU3  
    Print "Set lens index of refraction = " & nlens JRl8S   
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    '************************************************************************* N7Ne  
    'Pupil diameter b;S~`PL  
    '************************************************************************* u8o!ncy  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) T0aK1Lh  
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    'Adjust pupil diameter (trimming volume inner hole) m6g+ B>  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" lOZ.{0{f,  
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    ' Adjust pupil location to just in front of the lens abI[J]T9G  
    parID = FindFullName( "Geometry.Arizona Eye" ) >~XX'}  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Lmj?V1% V  
    count = 0 ~~k IA"U  
    While GetOperationCount(eID)>count %f, 9  
        GetOperation eID, count, op KnU"49  
        If op.Type="ShiftZ" Then `ORDN|s6  
            DeleteOperation eID,count VsUEp_I  
            count=count-1 I ][8[UZ  
        End If [0_Kz"|  
        count=count+1 f~"3#MaV  
    Wend A$|> Jt  
    op.Type = "ShiftZ" 1!=$3]l0Lj  
    op.val1 = taq-0.01 AKL~F|t  
    op.parent = parID 8/=[mYn`-  
    AddOperation eID, op ^3*gf}  
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    Print "Set pupil diameter = " & pupilDiam U6_1L,W  
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    'Update AZ Eye subassembly Description }V9146  
    eID = FindFullName( "Geometry.Arizona Eye" ) d9sgk3K  
    GetEntity eID, entity 2X6y^f';\  
    entity.Description = "Accommodation = " & A & "D" I,?bZ&@8  
    SetEntity eID, entity u}#rS%SF*  
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    Update +n)(\k{  
    Print "DONE!" R2M,VK?Wx  
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End Sub 4 (Y5n?/  
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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： _+^3<MT  
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Accommodation = 4 Diopters i|=}zR  
Pupil Diameter = 4 mm ~ |!q>z  
Set aqueous humor thickness = 2.81 F3wRHq  
Set anterior lens radius = 10.4 and conic constant = -2.375869 c~c3;  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 WgY\m&  
Set lens thickness = 3.927 BNzL+"W  
Set lens index of refraction = 1.42672 {d )Et;_  
Set pupil diameter = 4 ,PIdPaV--  
DONE! ?g<*1N?:  
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（文章来源：讯技光电）
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