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。 0]KraLu"N
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模型 oVA?J%EK
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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。 kIw`P[

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. +;$oJJ
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光源 ;k"Bse!/
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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。 f.aSKQD
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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。 _Jwq`]Z
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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。 u p.Q>28r

图2. 字母F光源的设定方法光 ~$'\L

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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 7g R@$(1Z
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在散射文件中，有一个名为“Retina surface”的72%的反射型朗伯散射，它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射，改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 o7mZzzP
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义，在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳，半角度10度。 D9`0Dr}/2
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图5. 视网膜重点采样规格设定
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脚本 pF ^#}L
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框，如下图所示： (`SRJ$~f

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。 lKEkXO
余下的脚本计算与屈光度有关的所有参数。 ?Ma~^0
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分析 {R/C0-Q^^
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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。 m*$|GW9

图7. 字母F在视网膜上颜色分析
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脚本代码 h"H2z1$
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. qlA7tU2p&
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Dim entity As T_ENTITY ]xguBh]
Dim op As T_OPERATION rP!#RzL
Dim mat As T_MODELMATERIAL WK="J6K5
Dim A As Double 6a;v&5
Dim pupilDiam As Double `/HUV&i"S
Dim eID As Long %pXAeeSY`;
Dim parID As Long cBo{/Tn:
Dim count As Integer 97K[(KE
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 0rGSH*(
Dim tlens As Double, nlens As Double 9CCkqB/
Dim curv As Double, conic As Double 7LO%#No",
Dim ok As Long lN9=TxH1(;
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Sub Main CRbdAqofV
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    '用户输入对话框 0%)i<a!_Z
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 9b?SHzAa
        TextBox 220,21,40,21,.TextBox1 'default: 0 xQw7 :18wQ
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 O@?kT;B
        OKButton 40,91,90,21 q5>v'ZSo
        CancelButton 190,91,90,21 z5W@`=D
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 PQ@L+],C
        TextBox 220,49,40,21,.TextBox2 'default: 4 Jvun?J m
    End Dialog 4(-bx.V
    Dim dlg As UserDialog c{[q>@y pK
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    ok = Dialog (dlg) erVO|<%=R
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    If ok=0 Then    'cancel button was pressed N?X^O#[
        Print "Execution cancelled." 5MzFUv0)
        End 1Z{ZV.!
    End If V5U?F6
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    'Assign accommodation and pupil diameter & use defaults if field left empty ^<X@s1^#
    If dlg.TextBox1 = "" Then 9:I6( Zv0
        A = 0           'Default accommodation @-OnHE
    Else QMEcQV>
        A = CDbl(dlg.TextBox1) w,Ee>cV]a
    End If L.]$6Q0
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    If dlg.TextBox2 = "" Then .Vq)zi1<
        pupilDiam = 4   'Default pupil diameter _,</1~.
    Else m!U9m
        pupilDiam = CDbl(dlg.TextBox2) M`6y@<
    End If c^`]`xiX
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    Print " " b*ef);
    Print "Accommodation = " & A & " Diopters" ""Q1|
    Print "Pupil Diameter = " & pupilDiam & " mm" d6i6hcQE
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    ' Calculate new parameters with accommodation LL$_zK{
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ~SSU`
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens YIR R=qpn
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens I7^zU3]Ul
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens @]bPVG?d
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 67y Tvr@a
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    tlens = 3.767 + 0.04*A                  'Lens thickness d,$d~alY
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction r]ShZBAbYp
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    'Adjust parameters to account for accommodation 5{$LsL
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    '************************************************************************* !a$ D4(`v
    'Aqueous thickness (Position of Lens) ^T~gEv
    '************************************************************************* Pl-5ncb\
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) B^%1Rpcn
    GetCustomElement eID, entity >&!RWH9*q
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    parID = FindFullName( "Geometry.Arizona Eye" ) Dz./w
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    ' Delete any shift(s) in z /.M+fr S
    count = 0 _bD/D!|
    While GetOperationCount(eID)>count qaim6a
        GetOperation eID, count, op 2YuN~-
        If op.Type="ShiftZ" Then KN"S?i]X
            DeleteOperation eID,count +y 87~]]
            count=count-1 X,8<oX1r
        End If Z0De!?ALV\
        count=count+1 sE{pzPq!
    Wend 5'a3huRtV
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    'Set new shift in "n:{!1VGw
    op.Type = "ShiftZ" 2BCtJ`S`
    op.val1 = taq ET];%~ ^
    op.parent = parID OGiV{9U
    AddOperation eID, op +\Q?w?DE|
    Print "Set aqueous humor thickness = " & taq-0.55 G|8%qd
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    '************************************************************************* -CH`>
    'Radius and conic constant of anterior lens !A1)|/a@
    '************************************************************************* Xtq{%
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) I]!^;))
    GetConic eID, entity, curv, conic ?OdJqw0,G
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    SetConic eID, entity, 1/Rant, CCant Q !qrNa6
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant a{Esw`
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    '************************************************************************* )5fQ$<(Z
    'Radius and conic constant of posterior lens H UoyLy
    '************************************************************************* | nJZie8m
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) L}#0I+Ml7
    GetConic eID, entity, curv, conic 2wqk,c[]
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    SetConic eID, entity, 1/Rpost, CCpost H;aYiy
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 5BR5X\f0
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    '************************************************************************* :ug4g6;#H0
    'Lens thickness (Position of posterior lens surface) p1c3Q$>i
    '************************************************************************* FZiW|G
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Cc?TSZ8[
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    ' Delete any z-shift(s) PN+G:Qv
    count = 0 pS4&w8s
    While GetOperationCount(eID)>count avp;*G}
        GetOperation eID, count, op 7 1W5.!
        If op.Type="ShiftZ" Then 1p`+
            DeleteOperation eID,count 9]$8MY
            count=count-1 hgRVwX
        End If JFL>nH0mk.
        count=count+1 =rPrPb
    Wend t4Z
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    'Set new z-shift N^VD=<#T
    op.Type = "ShiftZ" bshGS8O
    op.val1 = tlens ea=83 Zj
    op.parent = parID CLKov\U\
    AddOperation eID, op 04!(okubyp
    Print "Set lens thickness = " & tlens {+zJI-XN/
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    '************************************************************************* *p ? e.%nd
    'Lens index of refraction !\[+99F#
    '************************************************************************* =R*Gk4<Y
    eID = FindMaterial( "Lens" ) B6Ej{q^k,
    GetModelMaterial eID, mat Hg}I]!B
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    mat.Nd = nlens *5%*|>
    SetModelMaterial eID, mat VVWM9x
    Print "Set lens index of refraction = " & nlens YC_3n5F%
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    '************************************************************************* E& 36H
    'Pupil diameter o?Sla_D
    '************************************************************************* bAxTLIf
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) e`{0d{Nd
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    'Adjust pupil diameter (trimming volume inner hole) /7$mxtB5%L
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 2>S~I"o0
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    ' Adjust pupil location to just in front of the lens X_; *`,<T
    parID = FindFullName( "Geometry.Arizona Eye" ) HW=xvA+
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) V'Y{v
    count = 0 )Du-_Z
    While GetOperationCount(eID)>count b`cYpcs
        GetOperation eID, count, op 1H:ea7YVU
        If op.Type="ShiftZ" Then 8dT'xuch
            DeleteOperation eID,count >Pe:I
            count=count-1 E(+T*
        End If VmQh$&h
        count=count+1 Q882B1H
    Wend {j(4m
    op.Type = "ShiftZ" !>;w!^U
    op.val1 = taq-0.01 PB~_I=
    op.parent = parID %/0gWG
    AddOperation eID, op Zcd7*EBdx
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    Print "Set pupil diameter = " & pupilDiam ucg$Ed
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    'Update AZ Eye subassembly Description ` DCU>bt&R
    eID = FindFullName( "Geometry.Arizona Eye" ) {ctwo X[;
    GetEntity eID, entity si/er"&o
    entity.Description = "Accommodation = " & A & "D" rb_Z5T
    SetEntity eID, entity 9n}A ^
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    Update >M^&F6
    Print "DONE!" \3NS>v[1
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End Sub 5ouQQ)vA
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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： 2tr :xi@
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Accommodation = 4 Diopters ,zgNE*{Y"4
Pupil Diameter = 4 mm AF#_nK)@
Set aqueous humor thickness = 2.81 +BB0wY
Set anterior lens radius = 10.4 and conic constant = -2.375869 X7cWgo66T
Set posterior lens radius = -4.424557 and conic constant = -3.081019 9G:TW|)L[Q
Set lens thickness = 3.927 IlHY%8F{
Set lens index of refraction = 1.42672 rnvQ<671W
Set pupil diameter = 4 ]xq::a{Oy
DONE!
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