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。 S*:b\{[f>
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模型 1dOVH7
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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。 aU2O5z&

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. P}H7WH
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光源 I`2hxLwh+
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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。 pHY~_^B4&
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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。 `jJ5us
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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。 q[l},nw

图2. 字母F光源的设定方法光 ekfD+X

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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 :h N*
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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。 OUe@U;l{Z
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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。 DVRE;+Jt
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图5. 视网膜重点采样规格设定
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脚本 %?_pSH}$!
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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： Zo22se0)

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。 :sFP{rFx~
余下的脚本计算与屈光度有关的所有参数。 RT8xU;
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分析 N|T%cdh:/
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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。 ^x4I

图7. 字母F在视网膜上颜色分析
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脚本代码 Wj/.rG&tE
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. rcPP-+XW
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Dim entity As T_ENTITY G{i}z^n
Dim op As T_OPERATION P6zy<w
Dim mat As T_MODELMATERIAL ]k_@F6 A
Dim A As Double P8Fq %k
Dim pupilDiam As Double uY,&lX+!
Dim eID As Long fnG&29x
Dim parID As Long )Rn}4)9!iT
Dim count As Integer 0ho+Y@8
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double sYiegX`1c
Dim tlens As Double, nlens As Double VieC+Kk
Dim curv As Double, conic As Double T c4N\Cy
Dim ok As Long j>+x|!k
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Sub Main l];,)ddD9
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    '用户输入对话框 LXG,IG
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 /,f*IdB
        TextBox 220,21,40,21,.TextBox1 'default: 0 +eZR._&0
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 !%_Z>a
        OKButton 40,91,90,21 H ZIJKk(
        CancelButton 190,91,90,21 ync2X{9D
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 =K=FzV'_~
        TextBox 220,49,40,21,.TextBox2 'default: 4 mrX3/e
    End Dialog GNA:|x
    Dim dlg As UserDialog 5*{U!${a
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    ok = Dialog (dlg) Bl2y~fCA
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    If ok=0 Then    'cancel button was pressed "~9 !o"
        Print "Execution cancelled." ((\s4-
        End !iWPldn&]
    End If KcglpKV`
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    'Assign accommodation and pupil diameter & use defaults if field left empty PCH&eTKN
    If dlg.TextBox1 = "" Then ~&[Wqn@MZ
        A = 0           'Default accommodation .vj`[?T
    Else }a,j1r_Hl&
        A = CDbl(dlg.TextBox1) }xn\.M:ic
    End If v9(->X'
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    If dlg.TextBox2 = "" Then L"&j(|{
        pupilDiam = 4   'Default pupil diameter 57Q^"sl
    Else fD
        pupilDiam = CDbl(dlg.TextBox2) x1W<r)A )r
    End If -~~"}u
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    Print " " YgNt>4K
    Print "Accommodation = " & A & " Diopters" p [4/Nq,c
    Print "Pupil Diameter = " & pupilDiam & " mm" >c*}Do{lG
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    ' Calculate new parameters with accommodation F=U3o=-:
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 8Gzc3
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens jxU1u"WU
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens UB }n=
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens nR-`;lrF~
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Ci0:-IS
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    tlens = 3.767 + 0.04*A                  'Lens thickness "ys#%,Z
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Ol1[o
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    'Adjust parameters to account for accommodation 5:6as^i:b
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    '************************************************************************* Lg0Vn&k
    'Aqueous thickness (Position of Lens) LFvKF.
    '************************************************************************* oMawINDa
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) \ce (/I
    GetCustomElement eID, entity v=zqj}T
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    parID = FindFullName( "Geometry.Arizona Eye" ) "Lk-R5iFd
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    ' Delete any shift(s) in z D::$YR ~R
    count = 0 _fx0-S*$
    While GetOperationCount(eID)>count \Y&*sfQ
        GetOperation eID, count, op u[q1]]
        If op.Type="ShiftZ" Then ;UTT>j
            DeleteOperation eID,count 6!bp;iLKy
            count=count-1 Fk@A;22N
        End If +b"RZ:tKp
        count=count+1 rxH*h`Xx@
    Wend }CnqJ@>C5
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    'Set new shift in *{8<4CVv
    op.Type = "ShiftZ" QlmZBqK}&
    op.val1 = taq GO{o #}
    op.parent = parID ,e{(r0
    AddOperation eID, op ?K%&N99c!
    Print "Set aqueous humor thickness = " & taq-0.55 L1A0->t
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    '************************************************************************* H=Rqr
    'Radius and conic constant of anterior lens GxE"q-G
    '************************************************************************* ~SgW+sDFu
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) $zS0]@Dj
    GetConic eID, entity, curv, conic 7?a@i;E<
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    SetConic eID, entity, 1/Rant, CCant dR~4*59Bg
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant vH/z|<
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    '************************************************************************* l*_%K}%?V
    'Radius and conic constant of posterior lens }#}IR5`=E
    '************************************************************************* d MQ]=
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) bh9rsRb}O
    GetConic eID, entity, curv, conic to{/@^ D
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    SetConic eID, entity, 1/Rpost, CCpost ]vj4E"2;
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost R|aA6} /I
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    '************************************************************************* $MD|YW5
    'Lens thickness (Position of posterior lens surface) rvO7e cR"
    '************************************************************************* t I}@1
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) *)0bifw$&
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    ' Delete any z-shift(s) q] g'rO'
    count = 0 v Yt-Nx
    While GetOperationCount(eID)>count B;xw @:H
        GetOperation eID, count, op [=M0%"
        If op.Type="ShiftZ" Then k[lYdk
            DeleteOperation eID,count %\6ns
            count=count-1 y,&.<Yc
        End If AZ' "M{wiI
        count=count+1 _/;k;$gDp
    Wend LDlj4>%pW^
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    'Set new z-shift UB[tYZ
    op.Type = "ShiftZ" C@+"d3
    op.val1 = tlens <[{Ty+
    op.parent = parID (2J_Y*N~>
    AddOperation eID, op k^3 ?Z2a
    Print "Set lens thickness = " & tlens ?^]29p_
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    '************************************************************************* o('W2Bs-o
    'Lens index of refraction mD}&X7
    '************************************************************************* {Ic~}>w
    eID = FindMaterial( "Lens" ) H|8vW
    GetModelMaterial eID, mat = 7U^pT
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    mat.Nd = nlens 6<0-GD}M
    SetModelMaterial eID, mat 9_Tk8L#
    Print "Set lens index of refraction = " & nlens 2 mM0\ja
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    '************************************************************************* 48X;'b,h
    'Pupil diameter &t)dE7u5
    '************************************************************************* YrAaL"20
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) .5=Qfvi*
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    'Adjust pupil diameter (trimming volume inner hole) jU')8m[
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" (ov=D7>t0
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    ' Adjust pupil location to just in front of the lens \+OP!`
    parID = FindFullName( "Geometry.Arizona Eye" ) d"zbY\`
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 2`4'Y.Qf
    count = 0 &sbA:xZBA
    While GetOperationCount(eID)>count cU}j Whu
        GetOperation eID, count, op 0gY,[aQ2
        If op.Type="ShiftZ" Then i<<NKv8;
            DeleteOperation eID,count cJ9:XWW
            count=count-1 MGn:Gj"d
        End If KQsS)ju
        count=count+1 bni :B?#
    Wend (QQ/I;
    op.Type = "ShiftZ" C~o6]'+F_
    op.val1 = taq-0.01 X\3IY:Q@T
    op.parent = parID 1B~H*=t4h
    AddOperation eID, op )W^Wqa8mG|
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    Print "Set pupil diameter = " & pupilDiam W]|;ZzZ=m
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    'Update AZ Eye subassembly Description ahgm*Cpc
    eID = FindFullName( "Geometry.Arizona Eye" ) }>:v
    GetEntity eID, entity >T3HkOT
    entity.Description = "Accommodation = " & A & "D" +gb2>fei&
    SetEntity eID, entity >W2Z]V
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    Update 1G/bqIMg63
    Print "DONE!" Qxj &IX
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End Sub @]lKQZ^2&
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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： .Ajs0 T2
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Accommodation = 4 Diopters s+?r4t3H!
Pupil Diameter = 4 mm @ -pi
Set aqueous humor thickness = 2.81 =]x FHw8A
Set anterior lens radius = 10.4 and conic constant = -2.375869 ,X6.p
Set posterior lens radius = -4.424557 and conic constant = -3.081019 +=I_3Wtth
Set lens thickness = 3.927 `+]9+:tS
Set lens index of refraction = 1.42672 k!E`Xeob
Set pupil diameter = 4 TL@_m^SM
DONE!
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