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。 p{W'[A{J .
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模型 Rw]lW;EN<
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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。 DQyy">]Mh

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. _6Qb 3tl
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光源 gf^XqTLs
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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。 "fZWAGDBO\
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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。 =,G^GMi'
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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。 ?CO..l

图2. 字母F光源的设定方法光 ql2O%B.6?

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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 1`v$R0`!
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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。 ,l7',@6Y
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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。 6hAMk<kx?i
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图5. 视网膜重点采样规格设定
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脚本 wLOS,=
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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： M TOZ:b

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。 >@uFye$
余下的脚本计算与屈光度有关的所有参数。 = @n`5g
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分析 /\u1q<
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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。 xY$@^(Q\

图7. 字母F在视网膜上颜色分析
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脚本代码 :,1kSM%r
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. Q/^a(
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Dim entity As T_ENTITY %w#8t#[,6
Dim op As T_OPERATION 7xoq:oP-}N
Dim mat As T_MODELMATERIAL %hV]vm
Dim A As Double xay~fD
Dim pupilDiam As Double `z~L0h
Dim eID As Long $@@@</VbP
Dim parID As Long 7]lUPLsl
Dim count As Integer Tv /?-`Y
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double <)VNEy'
Dim tlens As Double, nlens As Double $.T\dm-
Dim curv As Double, conic As Double se`^g ,]P
Dim ok As Long I6RF;m:Jw
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Sub Main u]jvXPE6
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    '用户输入对话框 /{FSG!
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 gN5;Uk
        TextBox 220,21,40,21,.TextBox1 'default: 0 B> V)6\
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 rkWiGiisM
        OKButton 40,91,90,21 5[|ZceY
        CancelButton 190,91,90,21 $i"IOp
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 _8&a%?R@W
        TextBox 220,49,40,21,.TextBox2 'default: 4 (;cvLop
    End Dialog CjZIBMGc
    Dim dlg As UserDialog JE ''Th}
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    ok = Dialog (dlg) [VY265)g
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    If ok=0 Then    'cancel button was pressed ~R C\
        Print "Execution cancelled." EKf!j3
        End _l{_n2D-
    End If O2N~&<^
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    'Assign accommodation and pupil diameter & use defaults if field left empty Gc2:^FVlh
    If dlg.TextBox1 = "" Then B(,j*,f
        A = 0           'Default accommodation (=t41-l
    Else Z^6qxZJ7
        A = CDbl(dlg.TextBox1) :@K~>^+U
    End If VJOB+CKE
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    If dlg.TextBox2 = "" Then Q1[EiM3
        pupilDiam = 4   'Default pupil diameter IZOO>-g'f
    Else buA/G-<e
        pupilDiam = CDbl(dlg.TextBox2) iPdR;O'
    End If mG.H=iw
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    Print " " mt}3/d
    Print "Accommodation = " & A & " Diopters" qTI_'q
    Print "Pupil Diameter = " & pupilDiam & " mm" ((T6z$:hA
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    ' Calculate new parameters with accommodation !<= ^&\A
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness aqKrf(Rv
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens O1Nya\^g<I
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens lc\%7-%:5
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens r;SOAucX
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens '.IR|~Y
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    tlens = 3.767 + 0.04*A                  'Lens thickness UqNUP+K
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 2aJ_[3p/h]
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    'Adjust parameters to account for accommodation |G(I,EPag
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    '************************************************************************* 'DTq<`~?
    'Aqueous thickness (Position of Lens) yt#~n_
    '************************************************************************* "HtaJVp//
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) To =JE}jzo
    GetCustomElement eID, entity g96]>]A<{
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    parID = FindFullName( "Geometry.Arizona Eye" ) $Qcr8~+a
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    ' Delete any shift(s) in z 1)J' pDa
    count = 0 R/jHH{T3
    While GetOperationCount(eID)>count u+qj_Ej
        GetOperation eID, count, op X.[8L^ldh
        If op.Type="ShiftZ" Then Tzr'3m_
            DeleteOperation eID,count 2 sK\.yS
            count=count-1 cS RmC
        End If n7pjj
        count=count+1 J7p?9
    Wend GU7f27p
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    'Set new shift in ][B>`gC-
    op.Type = "ShiftZ" a\tv,Lx
    op.val1 = taq _[,7DA.qc
    op.parent = parID ="P&!lu
    AddOperation eID, op $Go)Zs-bL?
    Print "Set aqueous humor thickness = " & taq-0.55 z? Ck9
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    '************************************************************************* 4q*mEV
    'Radius and conic constant of anterior lens 4%5 +
    '************************************************************************* @6%o0p9zz
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) :I8HRkp
    GetConic eID, entity, curv, conic 8K2=WYN
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    SetConic eID, entity, 1/Rant, CCant K(rWM>Jv
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant lS/l iI'Y
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    '************************************************************************* =DwY-Ex
    'Radius and conic constant of posterior lens tf6 Zz[
    '************************************************************************* NE+ ;<mW
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) A$-\Er+f
    GetConic eID, entity, curv, conic s^HI%mdf
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    SetConic eID, entity, 1/Rpost, CCpost G<Y}QhFU
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost xM**n3SZ`
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    '************************************************************************* sF~!qag4q'
    'Lens thickness (Position of posterior lens surface) JzmX~|=Xi
    '************************************************************************* U &RZx&W
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Zx)gLDd
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    ' Delete any z-shift(s) $y,tR.5.)[
    count = 0 F[*/D/y(
    While GetOperationCount(eID)>count naVbcY
        GetOperation eID, count, op 70.Tm#qh
        If op.Type="ShiftZ" Then o8fY!C)
            DeleteOperation eID,count ,AwX7gx22
            count=count-1 T+41,
        End If .qs5xGg#9
        count=count+1 z m+3aF
    Wend Lm*PHG
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    'Set new z-shift 5=/j
    op.Type = "ShiftZ" <aQ5chf7
    op.val1 = tlens 1t}
    op.parent = parID 6UM1>xq9A
    AddOperation eID, op ei(S&u<
    Print "Set lens thickness = " & tlens q_Z6s5O
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    '************************************************************************* SLda>I(p7&
    'Lens index of refraction 2b&Fu\2Dmv
    '************************************************************************* R)6"P?h._4
    eID = FindMaterial( "Lens" ) VM<$!Aaz
    GetModelMaterial eID, mat xB5QM #w\
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    mat.Nd = nlens iH8V]%
    SetModelMaterial eID, mat v(p<88.!m
    Print "Set lens index of refraction = " & nlens ~W-5-Nl{s
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    '************************************************************************* ;*cCaB0u
    'Pupil diameter !Y10UmMu
    '************************************************************************* 2^y*O
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) D+y?KihE
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    'Adjust pupil diameter (trimming volume inner hole) V/BU(`~i
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" )j. .)o
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    ' Adjust pupil location to just in front of the lens WWT1_&0
    parID = FindFullName( "Geometry.Arizona Eye" ) !o\e/HGc!
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) gv,1 CK
    count = 0 sQn@:Gk
    While GetOperationCount(eID)>count MqRJ:x
        GetOperation eID, count, op >65\
        If op.Type="ShiftZ" Then OO\$'% y`
            DeleteOperation eID,count %e(DPX
            count=count-1 4+MaV<!tU^
        End If O]KQ]zN
        count=count+1 ]I\9S{?
    Wend cp6I]#X
    op.Type = "ShiftZ" 38GZ_z}r
    op.val1 = taq-0.01 B_*Ayk
    op.parent = parID L;v.X'f
    AddOperation eID, op &r2\P6J
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    Print "Set pupil diameter = " & pupilDiam 51;[R8'w
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    'Update AZ Eye subassembly Description A_crK`3
    eID = FindFullName( "Geometry.Arizona Eye" ) KxDp+]N]
    GetEntity eID, entity /7x1Z*Hg
    entity.Description = "Accommodation = " & A & "D" AF>t{rw=/
    SetEntity eID, entity /@&#U bN\
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    Update 4hzdc] a
    Print "DONE!" QOY{j
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End Sub hD{ `j
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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： [Y.=bfV!
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Accommodation = 4 Diopters TX;)}\
Pupil Diameter = 4 mm z\$(@:{A
Set aqueous humor thickness = 2.81 )iFXa<5h
Set anterior lens radius = 10.4 and conic constant = -2.375869 $W%-Mm
Set posterior lens radius = -4.424557 and conic constant = -3.081019 <h~=d("j
Set lens thickness = 3.927 zbgGK7
Set lens index of refraction = 1.42672 C[5dhFZ
Set pupil diameter = 4 ~K"nm{.
DONE!
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