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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 7l D-|yx  
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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。 H$KO[mW}  
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模型 wDJ`#"5p{  
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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。 =~B"8@B  
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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. DxJ;C09xNa  
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光源 qN $t_  
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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。 `*C=R  _  
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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。 YmziHns`b  
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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。 qt@L&v}~j  
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图2. 字母F光源的设定方法光 p+VU:%.t  
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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 =V^-@ji)b  
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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。 CMa6':~  
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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。 XKoY!Y\  
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图5. 视网膜重点采样规格设定
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脚本 d*gAL<M7E  
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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: |#oS7oV(  
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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。 Shm> r@C?  
余下的脚本计算与屈光度有关的所有参数。 8-q^.<9  
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分析 $Ome]+0  
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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。 NAbVH{*\U  
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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 hAGHb+:  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. JJ?{V:  
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Dim entity As T_ENTITY .E4* >@M5  
Dim op As T_OPERATION hXW` n*Zw  
Dim mat As T_MODELMATERIAL ex3Qbr  
Dim A As Double i+_LKHQN  
Dim pupilDiam As Double Y G+|r  
Dim eID As Long HA6tGZP*L  
Dim parID As Long !`DRJ)h  
Dim count As Integer ys[Li.s:  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double p>6`jr  
Dim tlens As Double, nlens As Double e+ xQ\LH  
Dim curv As Double, conic As Double $|K d<wv  
Dim ok As Long ><V*`{bD9)  
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Sub Main 3EoCEPb#  
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    '用户输入对话框 dG\ wW@}J  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 LQ+/|_(.  
        TextBox 220,21,40,21,.TextBox1 'default: 0  Z>[7#;;  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 vOQ% f?%G\  
        OKButton 40,91,90,21 dC11kq qj  
        CancelButton 190,91,90,21 u-_r2U  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 5!-TLwl`j\  
        TextBox 220,49,40,21,.TextBox2 'default: 4 bJ^JK  
    End Dialog dzVi ~wt_&  
    Dim dlg As UserDialog ho]:)!|VY  
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    ok = Dialog (dlg) 7|rH9Bc{U  
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    If ok=0 Then    'cancel button was pressed .~z'm$s1o  
        Print "Execution cancelled." @^{Hq6_`  
        End ]hl*6  
    End If Fq9YhR  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 8tY>%A~^z  
    If dlg.TextBox1 = "" Then @AyteHK  
        A = 0           'Default accommodation ] V D  
    Else .;#T<S "  
        A = CDbl(dlg.TextBox1) \kADh?phV  
    End If +pofN-*%  
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    If dlg.TextBox2 = "" Then d} >Po%r:  
        pupilDiam = 4   'Default pupil diameter TlG>)Z@/  
    Else TBlSZZ-55]  
        pupilDiam = CDbl(dlg.TextBox2) }@DCcf$<  
    End If +WX/4_STV  
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    Print " " 9zaN fs  
    Print "Accommodation = " & A & " Diopters" `lhw*{3A  
    Print "Pupil Diameter = " & pupilDiam & " mm" @W,jy$U  
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    ' Calculate new parameters with accommodation 'yo@5*x7  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ofvR0yV  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens j,IRUx13f  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens k"wQ9=HP7  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens KK|w30\f  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens )^(*B6;z5  
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    tlens = 3.767 + 0.04*A                  'Lens thickness iP:i6U]  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction t)SZ2G1r  
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    'Adjust parameters to account for accommodation cNll??j  
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    '*************************************************************************  hfB$4s9  
    'Aqueous thickness (Position of Lens) >.:+|Br`  
    '************************************************************************* A40DbD\^ad  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) qGk+4 yC  
    GetCustomElement eID, entity jNZ .Fb  
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    parID = FindFullName( "Geometry.Arizona Eye" ) H MOIUd  
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    ' Delete any shift(s) in z b?wrOS  
    count = 0 lg%fjBY  
    While GetOperationCount(eID)>count @T1G#[C~t  
        GetOperation eID, count, op kG^76dAQL  
        If op.Type="ShiftZ" Then I8#2+$Be+@  
            DeleteOperation eID,count GwWK'F'2  
            count=count-1 CEfqFn3^  
        End If UmKE]1Yw4r  
        count=count+1 Iix,}kzss  
    Wend S ?Zh#`(*  
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    'Set new shift in $QbJT`,mr  
    op.Type = "ShiftZ"  5"%.8P  
    op.val1 = taq LKN7L kl  
    op.parent = parID %-hSa~20  
    AddOperation eID, op {X,%GI  
    Print "Set aqueous humor thickness = " & taq-0.55 !Vpi1N\  
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    '************************************************************************* v>X!/if<y  
    'Radius and conic constant of anterior lens ~E}kwF  
    '************************************************************************* lZzW- %K  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) F`=p/IAJK  
    GetConic eID, entity, curv, conic FvT&nb{  
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    SetConic eID, entity, 1/Rant, CCant 3Tr,waV  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant W]4Z4&  
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    '************************************************************************* +.cpZqWn3  
    'Radius and conic constant of posterior lens :8S;34Y;  
    '************************************************************************* xU'z>y4V$  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) \p!UY 3'  
    GetConic eID, entity, curv, conic FgdnX2s J  
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    SetConic eID, entity, 1/Rpost, CCpost !Uiq3s`1T  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Va!G4_OT  
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    '************************************************************************* (Jp~=6&lKf  
    'Lens thickness (Position of posterior lens surface) FDo PW~+[  
    '*************************************************************************  bPsvoG  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) lHiWzt u  
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    ' Delete any z-shift(s) zC50 @S3|  
    count = 0 @@R Mm$  
    While GetOperationCount(eID)>count <4{m99  
        GetOperation eID, count, op z+Xr2B  
        If op.Type="ShiftZ" Then |v+z*}fKw  
            DeleteOperation eID,count fW = N  
            count=count-1 . 0dGS  
        End If  \? /'  
        count=count+1 &l6@C3N$  
    Wend m .++nF  
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    'Set new z-shift Z+B*V )a=  
    op.Type = "ShiftZ" zw#n85=  
    op.val1 = tlens 2poo@]M/  
    op.parent = parID _2KIe(,;  
    AddOperation eID, op RvG=GJJ9  
    Print "Set lens thickness = " & tlens ,#;hI{E  
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    '************************************************************************* '2X$. ^aW  
    'Lens index of refraction <^s31.&p  
    '************************************************************************* !B`z|#  
    eID = FindMaterial( "Lens" ) i]n2\v AG  
    GetModelMaterial eID, mat T]wC?gQG  
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    mat.Nd = nlens -9vNV:c  
    SetModelMaterial eID, mat |GMo"[  
    Print "Set lens index of refraction = " & nlens bo<P%$(D  
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    '************************************************************************* KHx2$*E_  
    'Pupil diameter {Q>OZm\+  
    '************************************************************************* <M9NyD`  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 4eWv).  
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    'Adjust pupil diameter (trimming volume inner hole) =`x }9|[  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ]x)!Kd2>  
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    ' Adjust pupil location to just in front of the lens "U^m~N9k{  
    parID = FindFullName( "Geometry.Arizona Eye" ) OROvy  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) /KvJjt'8  
    count = 0 .I_atv  
    While GetOperationCount(eID)>count HGAi2+&  
        GetOperation eID, count, op 4AN8Sx(  
        If op.Type="ShiftZ" Then *zUK3&n~I  
            DeleteOperation eID,count <ll?rPio"  
            count=count-1 wa<k%_# M  
        End If -] wEk%j  
        count=count+1 (:8a6=xQ  
    Wend W=HvMD  
    op.Type = "ShiftZ" \k5"&]I3  
    op.val1 = taq-0.01 A6[FH\f  
    op.parent = parID o2dO\$'  
    AddOperation eID, op k.C&6*l!5;  
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    Print "Set pupil diameter = " & pupilDiam SY|K9$M^  
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    'Update AZ Eye subassembly Description  2d*bF.  
    eID = FindFullName( "Geometry.Arizona Eye" ) &]YyV.  
    GetEntity eID, entity 7j)ky2r#  
    entity.Description = "Accommodation = " & A & "D" JPn)Op6  
    SetEntity eID, entity 2.WI".&y=  
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    Update S3M!"l  
    Print "DONE!" -E1-(TS  
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End Sub  @_f^AQ  
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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: Iuz_u2"C  
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Accommodation = 4 Diopters `(HvD] l  
Pupil Diameter = 4 mm FzEs1hpl  
Set aqueous humor thickness = 2.81 1J0gjO)AZ  
Set anterior lens radius = 10.4 and conic constant = -2.375869 \(Oc3+n6  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 +YZo-tE  
Set lens thickness = 3.927 .8W-,R4  
Set lens index of refraction = 1.42672 .;g kV-]  
Set pupil diameter = 4 ATqblU>D  
DONE! /69yR   
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