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。 U:7h>Z0W
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模型 )nm+_U
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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。 j=sfE qN).

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. +gl\l?>sr
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光源 T3w%y`K
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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。 zIa={tU
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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。 ;,{_=n>
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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。 i"Jy>'

图2. 字母F光源的设定方法光 Ww<Y]H$xZ<

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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 x^s,<G
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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>^
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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。 Ym'h vK
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图5. 视网膜重点采样规格设定
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脚本 z}vT8qoX
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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： `KQx#c>'

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。 fJFNS y
余下的脚本计算与屈光度有关的所有参数。 rPk|2l,E,3
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分析 xe@e#9N$
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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。 9#DXA}

图7. 字母F在视网膜上颜色分析
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脚本代码 l b(
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. Q<sqlh!h
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Dim entity As T_ENTITY S,5ok0R
Dim op As T_OPERATION t<rIg1
Dim mat As T_MODELMATERIAL YZ~MByu
Dim A As Double c7mKE`
Dim pupilDiam As Double J;& y?%{@5
Dim eID As Long l>6tEOXt
Dim parID As Long 2@S}x@^
Dim count As Integer +Tum K.
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double n>ryS/1
Dim tlens As Double, nlens As Double JBY.er`6C
Dim curv As Double, conic As Double .SC*!,
Dim ok As Long FJvY`zqB
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Sub Main rXB;#ypO
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    '用户输入对话框 GxdAOiq;
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 JxIJxhA>
        TextBox 220,21,40,21,.TextBox1 'default: 0 ;!<}oZp{
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 xXJ*xYn"}
        OKButton 40,91,90,21 Ph3;;,v '
        CancelButton 190,91,90,21 3d}v?q78
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 $zP5Hzx
        TextBox 220,49,40,21,.TextBox2 'default: 4 FL{Uz+Q
    End Dialog ?V6,>e_+
    Dim dlg As UserDialog iil<zEic
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    ok = Dialog (dlg) ]-gyXE1.r
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    If ok=0 Then    'cancel button was pressed .`Rt
        Print "Execution cancelled." @&\Y:aRO%i
        End d:)#-x*h7
    End If aHN"I
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    'Assign accommodation and pupil diameter & use defaults if field left empty AE rPd)yk0
    If dlg.TextBox1 = "" Then P j
        A = 0           'Default accommodation Gxw1P@<F:
    Else fZiAl7b!
        A = CDbl(dlg.TextBox1) 9q"kM
    End If Fi``l)Tt
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    If dlg.TextBox2 = "" Then qFmw9\Fn
        pupilDiam = 4   'Default pupil diameter W,4!"*+
    Else v#,queGi
        pupilDiam = CDbl(dlg.TextBox2) JL6$7h
    End If NzgG77>
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    Print " " Y-ao yoNS
    Print "Accommodation = " & A & " Diopters" Q^b&
    Print "Pupil Diameter = " & pupilDiam & " mm" ;wwc;wQ'
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    ' Calculate new parameters with accommodation E@GYl85fI
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >pF*unC;
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens uSfHlN4l
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ed6@o4D/kf
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens _[HZ[9c!
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens %#2$B+
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    tlens = 3.767 + 0.04*A                  'Lens thickness I!hh_
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction `;85Mo:qJ
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    'Adjust parameters to account for accommodation CXq[VYM&X
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    '************************************************************************* ^L%_kL_7
    'Aqueous thickness (Position of Lens) G'JHimP2j
    '************************************************************************* JX&U?Z
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) -PpcFLZ|
    GetCustomElement eID, entity O=jLZ2os
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    parID = FindFullName( "Geometry.Arizona Eye" ) RBQ8+^
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    ' Delete any shift(s) in z ?oYO !
    count = 0 NsB]f{7>8+
    While GetOperationCount(eID)>count QoYEWXT|g
        GetOperation eID, count, op Wj.t4XG!
        If op.Type="ShiftZ" Then \B#tB?rA
            DeleteOperation eID,count ^*AI19w!Ys
            count=count-1 S)U*1t7[
        End If |.)LZP,
        count=count+1 {b!{~q
    Wend X$!fR >Zc
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    'Set new shift in w;,34qbf
    op.Type = "ShiftZ" i)x0]XF
    op.val1 = taq f\2IKpF2
    op.parent = parID 27!FB@k-
    AddOperation eID, op v.]{b8RR
    Print "Set aqueous humor thickness = " & taq-0.55 BHr,jC
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    '************************************************************************* X7$]qE K
    'Radius and conic constant of anterior lens Q+Bl1xl
    '************************************************************************* $9YQ aN%
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) rn-bfzoDS
    GetConic eID, entity, curv, conic 7Yg1z%%U
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    SetConic eID, entity, 1/Rant, CCant 5|rBb[
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 5len}){
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    '************************************************************************* Z1,rN#p9
    'Radius and conic constant of posterior lens >J;TtNE:
    '************************************************************************* ZS.=GjK
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) |"}rdOV)
    GetConic eID, entity, curv, conic L-Q8iFW'
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    SetConic eID, entity, 1/Rpost, CCpost `"=Hk@E
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 7{<v$g$
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    '************************************************************************* q|ce7HnK
    'Lens thickness (Position of posterior lens surface) Sn[xI9}O
    '************************************************************************* ;n't:yQW
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) h3 HUdu
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    ' Delete any z-shift(s) ?;RY/[IX6
    count = 0 &>AwG4HW#j
    While GetOperationCount(eID)>count ;y(;7n_ a
        GetOperation eID, count, op J=-z~\f56
        If op.Type="ShiftZ" Then J!om"h
            DeleteOperation eID,count I7_8oq\3D
            count=count-1 ug,AvHEnB
        End If |pHlBzHj
        count=count+1 DCp8rvUI
    Wend _S) K+C|@
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    'Set new z-shift N'y<<tTA
    op.Type = "ShiftZ" a &tWMxBr
    op.val1 = tlens -Y524
    op.parent = parID , >WH)+a
    AddOperation eID, op eZ:iW#YF
    Print "Set lens thickness = " & tlens ,6]ID1o:y
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    '************************************************************************* lZAGoR;0Ra
    'Lens index of refraction ] !*K|?VL
    '************************************************************************* S }`f&
    eID = FindMaterial( "Lens" ) #[bosb!R
    GetModelMaterial eID, mat =+_nVO*
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    mat.Nd = nlens %1TKgNf
    SetModelMaterial eID, mat mo<*h&;&
    Print "Set lens index of refraction = " & nlens |"K%Tvxe
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    '************************************************************************* Y[e.1\d'
    'Pupil diameter _1?uAQ3,
    '************************************************************************* Pt85q?->
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) mW]dhY 3X
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    'Adjust pupil diameter (trimming volume inner hole) l1]N&jN{
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" U~=?I)Ni
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    ' Adjust pupil location to just in front of the lens "<|KR{/+
    parID = FindFullName( "Geometry.Arizona Eye" ) hYyIC:PXR
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \j!/l f)
    count = 0 }eSy]r[J
    While GetOperationCount(eID)>count 1 K}gX>F
        GetOperation eID, count, op @"s<0T^H
        If op.Type="ShiftZ" Then %qcCv9
            DeleteOperation eID,count :sw5@JdJ
            count=count-1 *i*\dl
        End If ~hq\XQX
        count=count+1 _f2rz+
    Wend TNh&g.
    op.Type = "ShiftZ" Otu?J_d3
    op.val1 = taq-0.01 ,l AZ4
    op.parent = parID )-X8RRw'
    AddOperation eID, op &L0Ii)Ns
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    Print "Set pupil diameter = " & pupilDiam Z?S?O#FED
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    'Update AZ Eye subassembly Description f'ld6jt|%
    eID = FindFullName( "Geometry.Arizona Eye" ) .feB VRg
    GetEntity eID, entity zU[o_[+7^
    entity.Description = "Accommodation = " & A & "D" ri-&3%%z<
    SetEntity eID, entity a9&[Qv5-/
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    Update DCa[?|Y
    Print "DONE!" r1q'+i
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End Sub ,l!>+@
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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： _b>z'4_'
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Accommodation = 4 Diopters Wk^{Tn/]
Pupil Diameter = 4 mm fqbWD)L]
Set aqueous humor thickness = 2.81 X`<z5W] !
Set anterior lens radius = 10.4 and conic constant = -2.375869 |{|B70v3Co
Set posterior lens radius = -4.424557 and conic constant = -3.081019 prM)t8SE
Set lens thickness = 3.927 J|jvqt9C
Set lens index of refraction = 1.42672 tHaHBx1P
Set pupil diameter = 4 N/lEfy<&g:
DONE!
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