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。 #@OPi6.#!<
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模型 ;veD?|
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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。 6 h#U,G

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. WYTqQqQk
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光源 Uzzm2OS`
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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。 Lu.+J]Rz
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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。 f\dfKNm6
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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。 rX?ZUw?u&

图2. 字母F光源的设定方法光 =/46;844T

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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 3._ ep
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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。 *PnO$q@`
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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。 Icrnu}pl_
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图5. 视网膜重点采样规格设定
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脚本 `R8&(kQ
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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： D1xGUz2r

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。 1]2]l*&3
余下的脚本计算与屈光度有关的所有参数。 < v]
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分析 dn- [Gnde
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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。 |cma7q}p

图7. 字母F在视网膜上颜色分析
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脚本代码 EYq?NL='
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. yKV{V?h?
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Dim entity As T_ENTITY E:pk'G0bZ
Dim op As T_OPERATION `sCaGCp
Dim mat As T_MODELMATERIAL (CxA5u1|l
Dim A As Double T(7`$<TQ
Dim pupilDiam As Double C!5A,|DX
Dim eID As Long +r8bGS]ki
Dim parID As Long _ Ncbo#G
Dim count As Integer W%g*sc*+
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ;yt6Yp.6e
Dim tlens As Double, nlens As Double 13!@LbC
Dim curv As Double, conic As Double ! dzgi:
Dim ok As Long h$l/wn
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Sub Main OT])t<TF6
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    '用户输入对话框 2H|:/y
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 |NfFe*q0;8
        TextBox 220,21,40,21,.TextBox1 'default: 0 'V:Q :
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 K?^;|m-
        OKButton 40,91,90,21 <xy@%
        CancelButton 190,91,90,21 @N>7+ 4
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 m;OvOc,
        TextBox 220,49,40,21,.TextBox2 'default: 4 d+JK")$9C
    End Dialog &$~fz":1!
    Dim dlg As UserDialog YJ _eE
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    ok = Dialog (dlg) 3^o(\=-JX
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    If ok=0 Then    'cancel button was pressed 6$k#B ~~
        Print "Execution cancelled." R{#< NE
        End t/iI!}
    End If AFz:%m
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    'Assign accommodation and pupil diameter & use defaults if field left empty a$My6Qa#
    If dlg.TextBox1 = "" Then K~ eak\=
        A = 0           'Default accommodation +94)BxrY
    Else > {*cW
        A = CDbl(dlg.TextBox1) U6]#RxH
    End If XNYA\%:5S
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    If dlg.TextBox2 = "" Then F(G..XJQ
        pupilDiam = 4   'Default pupil diameter Bs~~C8+
    Else OsgPNy0
        pupilDiam = CDbl(dlg.TextBox2) .q@?sdGD
    End If q#K{~:
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    Print " " <>] DcA
    Print "Accommodation = " & A & " Diopters" hw DxGiU
    Print "Pupil Diameter = " & pupilDiam & " mm" O*xx63%jR
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    ' Calculate new parameters with accommodation yE$PLM
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness U zy@\
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 66v,/#K
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Nm*(?1
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens gQ+]N*.
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 11H`WOTQF
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    tlens = 3.767 + 0.04*A                  'Lens thickness 6j%%CWU{~
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction h[ .
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    'Adjust parameters to account for accommodation 37U8<
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    '************************************************************************* V*p[6{U0
    'Aqueous thickness (Position of Lens) B"^j>SF
    '************************************************************************* noZbsI4
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) O=0p}{3l
    GetCustomElement eID, entity 'oa.-g5
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    parID = FindFullName( "Geometry.Arizona Eye" ) Fy=GU<&AI
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    ' Delete any shift(s) in z NQdwj>_a
    count = 0 x@-K
    While GetOperationCount(eID)>count k6tCfq;
        GetOperation eID, count, op Xb_ V\b0
        If op.Type="ShiftZ" Then S<mZs;
            DeleteOperation eID,count -X.#Y6(
            count=count-1 e={O&9Z
        End If 2I.FSR_G?
        count=count+1 '}OdF*L
    Wend '@n"'vks(\
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    'Set new shift in #VQZ"7nI@
    op.Type = "ShiftZ" *p{p.%Qs:
    op.val1 = taq |~9rak,
    op.parent = parID l)u%`Hcn
    AddOperation eID, op dwA"QVp{
    Print "Set aqueous humor thickness = " & taq-0.55 }z]d]
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    '************************************************************************* i~!g9o(
    'Radius and conic constant of anterior lens +ai3
    '************************************************************************* }QE.|.fA1
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xQ9t1b|{e
    GetConic eID, entity, curv, conic zw<<st Bp
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    SetConic eID, entity, 1/Rant, CCant .][yH[F
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant S^s-md>
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    '************************************************************************* <"Y>|X
    'Radius and conic constant of posterior lens dsIbr"m
    '************************************************************************* 8:Hh;nl
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) F}Zg3#
    GetConic eID, entity, curv, conic ;MfqI/B{
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    SetConic eID, entity, 1/Rpost, CCpost ^B.Z3Y
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost wBt7S!>G
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    '************************************************************************* )Kx.v'
    'Lens thickness (Position of posterior lens surface) .-$3I|}X=
    '************************************************************************* Sct
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) SFg4}*"C/
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    ' Delete any z-shift(s) ivo3pibk%
    count = 0 $HwF:L)*
    While GetOperationCount(eID)>count 3Ei^WDJ
        GetOperation eID, count, op EWJB/iED
        If op.Type="ShiftZ" Then QMMpB{FZ`o
            DeleteOperation eID,count uGAQt9$>_
            count=count-1 $NCvF'
        End If f@sC~A. 9\
        count=count+1 }P.s
    Wend 0LW3VfvToN
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    'Set new z-shift Rd8mn'A
    op.Type = "ShiftZ" WvU[9ME^)
    op.val1 = tlens <.`i,|?MHS
    op.parent = parID WX Fm'5Vr
    AddOperation eID, op /CALXwL
    Print "Set lens thickness = " & tlens PE{<'K\g
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    '************************************************************************* @+;.W>^h
    'Lens index of refraction t|>P9lX@
    '************************************************************************* G5hRx@vfrL
    eID = FindMaterial( "Lens" ) /yU#UZ4;
    GetModelMaterial eID, mat @zGF9O<3,@
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    mat.Nd = nlens o2|#_tGNUy
    SetModelMaterial eID, mat XY)X-K$
    Print "Set lens index of refraction = " & nlens N+~ MS3
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    '************************************************************************* +PPQ"#1pS
    'Pupil diameter Z7wl~Hk
    '************************************************************************* )4fQ~)
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) /%&5Iq\:vA
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    'Adjust pupil diameter (trimming volume inner hole) M_0f{
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" :V$\y up
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    ' Adjust pupil location to just in front of the lens ]9_tto!/
    parID = FindFullName( "Geometry.Arizona Eye" ) v$\<L|
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) "} :CM_
    count = 0 _G)A$6weU
    While GetOperationCount(eID)>count v2gk1a&
        GetOperation eID, count, op a /]FlT
        If op.Type="ShiftZ" Then (e_<~+E
            DeleteOperation eID,count = y^5PjN
            count=count-1 4SUzR\
        End If BN&)5M?Xt6
        count=count+1 1N65 M=)
    Wend ,g'>Ib%
    op.Type = "ShiftZ" AyUw
    op.val1 = taq-0.01 :~vg'v~C
    op.parent = parID cK[=IE5
    AddOperation eID, op 7oZPb
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    Print "Set pupil diameter = " & pupilDiam eSIG+{;&
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    'Update AZ Eye subassembly Description 6yYjZ<
    eID = FindFullName( "Geometry.Arizona Eye" ) v?8i;[
    GetEntity eID, entity ?@in($67
    entity.Description = "Accommodation = " & A & "D" IjOBY
    SetEntity eID, entity 6 o
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    Update &b>&XMIK
    Print "DONE!" ,^n&Q'p3
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End Sub k|>yFc
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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： rYV]<[?~7
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Accommodation = 4 Diopters {o^tSEN!-
Pupil Diameter = 4 mm 4n.JRR&;
Set aqueous humor thickness = 2.81 Uufig)6
Set anterior lens radius = 10.4 and conic constant = -2.375869 IlO,Ql
Set posterior lens radius = -4.424557 and conic constant = -3.081019 0N)DHD?U
Set lens thickness = 3.927 M^OYQf
Set lens index of refraction = 1.42672 xC5Pv">
Set pupil diameter = 4 Mb"y{Fox
DONE!
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