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xunjigd 2016-02-24 12:53

FRED运用：Arizona眼睛模型

简介 8HyK;+ZkVd  
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。 [=Yfdh M8S  
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模型 X>#!s Lt  
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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。 f}'E|:Z 7k  
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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. uz1t uX_  
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光源 WlnI`!)d  
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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。 )up!W4h6o  
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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。 ba3_5 5]  
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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。 ,!f*OWnZ  
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图2. 字母F光源的设定方法光 7ST[XLwt%}  
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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 ) tGC&l+?/  
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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。 XY5I5H_U  
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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。 DiAPs_@  
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图5. 视网膜重点采样规格设定
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脚本 w$7*za2  
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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： bgd1j,PWbW  
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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。 DY6wp@A  
余下的脚本计算与屈光度有关的所有参数。 S5'BXE,  
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分析 nVoPTr  
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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。 +"a . ,-f!  
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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 ocy fU=}X  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. VuFH >8n  
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Dim entity As T_ENTITY (?&X<=|"  
Dim op As T_OPERATION a[)in ,3  
Dim mat As T_MODELMATERIAL j3~:\H  
Dim A As Double B5!$5 Qc  
Dim pupilDiam As Double @Q3aJ98)2  
Dim eID As Long X#(?V[F]  
Dim parID As Long $CO^dFf  
Dim count As Integer KLs%{'[7:  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ?T70C9  
Dim tlens As Double, nlens As Double w/N.#s^  
Dim curv As Double, conic As Double Fp-d69Npo  
Dim ok As Long )oa6;=go  
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Sub Main vI#\ Qe  
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    '用户输入对话框 7[:9vY  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ~d 7!)c`z  
        TextBox 220,21,40,21,.TextBox1 'default: 0 DVRE;+Jt  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 H(!)]dO  
        OKButton 40,91,90,21 )=;0  
        CancelButton 190,91,90,21 W=o90TwbN  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 NZ'S~Lr   
        TextBox 220,49,40,21,.TextBox2 'default: 4 9rtcI[&?0  
    End Dialog :Cw|BX@??U  
    Dim dlg As UserDialog R\MM2_I  
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    ok = Dialog (dlg) |~CN]N  
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    If ok=0 Then    'cancel button was pressed z![RC59 S  
        Print "Execution cancelled." veAGUE %3  
        End ~ DVAk|fc  
    End If qp^O\>c  
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    'Assign accommodation and pupil diameter & use defaults if field left empty w:Tz&$&Y$  
    If dlg.TextBox1 = "" Then _UYt  
        A = 0           'Default accommodation FlRbGg^  
    Else Wj/.rG&tE  
        A = CDbl(dlg.TextBox1) 4\Y2{Z>P?  
    End If rcPP-+XW  
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    If dlg.TextBox2 = "" Then .#6Dad=S*  
        pupilDiam = 4   'Default pupil diameter &n6mXFF#>P  
    Else %:N6#;l M  
        pupilDiam = CDbl(dlg.TextBox2) d /jO~+jP  
    End If *n N;!*J  
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    Print " " UBrYN'QRNt  
    Print "Accommodation = " & A & " Diopters" pRD8/7@(B{  
    Print "Pupil Diameter = " & pupilDiam & " mm" }?^5\otu  
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    ' Calculate new parameters with accommodation { o=4(RC  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness l];,)ddD9  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens @U_w:Q<9u  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens xpKD 'O=T  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ddmTMfH  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens SgHLs  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 9;k_"@A6  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction } '.l'%  
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    'Adjust parameters to account for accommodation t]#y} V  
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    '************************************************************************* h)"PPI  
    'Aqueous thickness (Position of Lens) { ,/mQ3  
    '************************************************************************* :se o0w]  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) I&U?8  
    GetCustomElement eID, entity '`#2'MXG  
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    parID = FindFullName( "Geometry.Arizona Eye" ) FRQ0tIp  
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    ' Delete any shift(s) in z DKAqQ?fS  
    count = 0 v9( ->X'  
    While GetOperationCount(eID)>count 'xm_oGWE  
        GetOperation eID, count, op OWx YV$  
        If op.Type="ShiftZ" Then z/)HJo2#  
            DeleteOperation eID,count "GEJ9_a[  
            count=count-1 U,yU-8z/  
        End If 3XYCtp8  
        count=count+1 +u#;k!B/>  
    Wend ZWQrG'$?o8  
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    'Set new shift in 7c1xB.g   
    op.Type = "ShiftZ" 6e(|t2^  
    op.val1 = taq v}!eJzeH  
    op.parent = parID Wp`wIe6  
    AddOperation eID, op {1;j1|CI  
    Print "Set aqueous humor thickness = " & taq-0.55 X(U CN0#  
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    '************************************************************************* w,cfSF;=tC  
    'Radius and conic constant of anterior lens V.vA~a  
    '************************************************************************* I$9^i#O'3  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Jiyt,D*wX  
    GetConic eID, entity, curv, conic s9>f5u?dK  
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    SetConic eID, entity, 1/Rant, CCant .p  NWd  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant  d!5C$C/x  
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    '************************************************************************* 5:6as^i:b  
    'Radius and conic constant of posterior lens ml<X92Y  
    '************************************************************************* Lg0Vn&k  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) LFvKF.  
    GetConic eID, entity, curv, conic oMawIND a  
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    SetConic eID, entity, 1/Rpost, CCpost v=zqj}T  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost "Kx2k>ym  
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    '************************************************************************* ?Y7'OlO  
    'Lens thickness (Position of posterior lens surface) ^AkVmsv;;  
    '************************************************************************* 55MrsiW  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) o^hI\9  
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    ' Delete any z-shift(s) pXf!8X&y  
    count = 0 d0$dQg  
    While GetOperationCount(eID)>count P9= L?t.  
        GetOperation eID, count, op *{8<4CVv  
        If op.Type="ShiftZ" Then QlmZBqK}&  
            DeleteOperation eID,count 7 ^7Rk  
            count=count-1 W iqlc  
        End If 1t haQ"  
        count=count+1 P0NGjS|Z{  
    Wend @RGVcfCG)  
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    'Set new z-shift gKy@$at&  
    op.Type = "ShiftZ" EN />f=%  
    op.val1 = tlens ~WXT0-,  
    op.parent = parID i1k(3:ay<  
    AddOperation eID, op WBD e`  
    Print "Set lens thickness = " & tlens ^j&'2n@ 9a  
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    '************************************************************************* P=PcO>  
    'Lens index of refraction )';Rb$<Qn  
    '************************************************************************* ~nJcHJ1nb4  
    eID = FindMaterial( "Lens" ) UQ6UZd37   
    GetModelMaterial eID, mat AoB~ZWq  
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    mat.Nd = nlens 'zCJK~x`x  
    SetModelMaterial eID, mat I;H6E  
    Print "Set lens index of refraction = " & nlens I{Hl2?CnI,  
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    '************************************************************************* c&r8q]u  
    'Pupil diameter jY>|>]4X  
    '************************************************************************* 0!X;C!v;  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) pwo5Ij,~q  
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    'Adjust pupil diameter (trimming volume inner hole) ^% y<7>%  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ^2Sa_.  
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    ' Adjust pupil location to just in front of the lens 4a3Xz,[(a  
    parID = FindFullName( "Geometry.Arizona Eye" ) B;Pws$J  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) #U45H.Rz  
    count = 0 1,@-y#V_  
    While GetOperationCount(eID)>count *V+6409m  
        GetOperation eID, count, op HDqPqrWm  
        If op.Type="ShiftZ" Then _=W ^#z  
            DeleteOperation eID,count [0|g3K !A  
            count=count-1 bB^% O^:  
        End If Hik8u!#P  
        count=count+1 n+Ofbiz@  
    Wend %-ih$ZY  
    op.Type = "ShiftZ" F02S(WWo;  
    op.val1 = taq-0.01 +~, qb1aZ  
    op.parent = parID *?jU$&Qpj*  
    AddOperation eID, op P Z5BtDm  
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    Print "Set pupil diameter = " & pupilDiam wn*<.s  
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    'Update AZ Eye subassembly Description N)'oX3?x  
    eID = FindFullName( "Geometry.Arizona Eye" ) v&g(6~b_>  
    GetEntity eID, entity xK4b(KJj  
    entity.Description = "Accommodation = " & A & "D" g-^Cf   
    SetEntity eID, entity ;0*T7l  
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    Update BM bT:)%  
    Print "DONE!" "=)i'x"0"  
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End Sub A WlR" p2  
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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： 0{|ib !  
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Accommodation = 4 Diopters -:9E+b  
Pupil Diameter = 4 mm x17cMfCH%  
Set aqueous humor thickness = 2.81 `>:ozN#)\  
Set anterior lens radius = 10.4 and conic constant = -2.375869 G<.p".o4  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 :@LFNcWE  
Set lens thickness = 3.927 |~mq+:44+  
Set lens index of refraction = 1.42672 s_Y1rD*B  
Set pupil diameter = 4 Xh==F:  
DONE! fuJ6 fmT  
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（文章来源：讯技光电）
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