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。 k_-=:(Z
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模型 DTlM}
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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。 4(bV#

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. xAjLn*d|N
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光源 |hiYV
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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。 hG2btmBht
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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。 pIC CjA?3@
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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。 .gG<08Z

图2. 字母F光源的设定方法光 ^ Gq2"rDM

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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 0u'4kF!P!
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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。 0{BPT>'
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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。 w>IkC+.?
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图5. 视网膜重点采样规格设定
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脚本 fB3O zff
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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： E:D1ZV

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。 SR*%-JbA
余下的脚本计算与屈光度有关的所有参数。 N>/*)Frt
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分析 >m:.5][yu
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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。 Zv7@

图7. 字母F在视网膜上颜色分析
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脚本代码 `RthX\Tof
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. Te[[xhTyw
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Dim entity As T_ENTITY 7v?tSob:b
Dim op As T_OPERATION S4qh8c
Dim mat As T_MODELMATERIAL 7@fd[
Dim A As Double ,RCjfXa
Dim pupilDiam As Double Kp~k!6x
Dim eID As Long nKu`Ta*fX
Dim parID As Long @!0j)5%
Dim count As Integer 3a!/EP
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double |GdA0y\v*}
Dim tlens As Double, nlens As Double w?jmi~6
Dim curv As Double, conic As Double g#9w5Q
Dim ok As Long 2}$Vi$ R
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Sub Main O<6/0ub&+h
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    '用户输入对话框 Mky$#SI11
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 zesEbR)j
        TextBox 220,21,40,21,.TextBox1 'default: 0 <Ks?g=K-
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 /D1Bf:'(
        OKButton 40,91,90,21 `Jm{K*&8Q
        CancelButton 190,91,90,21 @]3(l
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 &U4]hawbOU
        TextBox 220,49,40,21,.TextBox2 'default: 4 <'P|g
    End Dialog {D."A$AAa
    Dim dlg As UserDialog W.MJyem
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    ok = Dialog (dlg) D.*JG7;=Z
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    If ok=0 Then    'cancel button was pressed 7c %@2
        Print "Execution cancelled." EF"ar
        End t$l[ 4 R-
    End If M#<x2ojW
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    'Assign accommodation and pupil diameter & use defaults if field left empty m+OR W"o
    If dlg.TextBox1 = "" Then 1 _5[5K^
        A = 0           'Default accommodation `(Q58wR}
    Else v|{*y
        A = CDbl(dlg.TextBox1) y*uL,WH
    End If ;Jx ^
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    If dlg.TextBox2 = "" Then AQQj]7Y
        pupilDiam = 4   'Default pupil diameter {/QpEd>3+
    Else ZN1QTb
        pupilDiam = CDbl(dlg.TextBox2) cLR8U1k'
    End If UwE^ij
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    Print " " f{3FoN=z
    Print "Accommodation = " & A & " Diopters" ulj`+D?H
    Print "Pupil Diameter = " & pupilDiam & " mm" a#uJzYB0
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    ' Calculate new parameters with accommodation /)oxuk&}c
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness "hy#L 0\t
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ;P2~cQjD;
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens gvcT_'
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens K[?wP>s
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens zcxG%? Q
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    tlens = 3.767 + 0.04*A                  'Lens thickness 3_33@MM
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction >`oO(d}n[0
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    'Adjust parameters to account for accommodation %+pXzw`B
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    '************************************************************************* X0!48fL*
    'Aqueous thickness (Position of Lens) xUSIck
    '************************************************************************* 7kJ,;30)
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Q45rP4mQ
    GetCustomElement eID, entity .Dx]wv
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    parID = FindFullName( "Geometry.Arizona Eye" ) ait/|a
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    ' Delete any shift(s) in z v WhtClJ3
    count = 0 @l;f';+
    While GetOperationCount(eID)>count w^ DAu1
        GetOperation eID, count, op }'@*Olj
        If op.Type="ShiftZ" Then SnXYq7`t
            DeleteOperation eID,count @NyCMe;]
            count=count-1 ^3r2Q?d\
        End If g8qN+Gg
        count=count+1 Q0 ^?jh
    Wend YEZ"BgUnbp
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    'Set new shift in T 7 hC]R
    op.Type = "ShiftZ" 5,mb]v0k
    op.val1 = taq 5k\61(*s
    op.parent = parID Ql\GL"
    AddOperation eID, op Z>X-ueV
    Print "Set aqueous humor thickness = " & taq-0.55 54'z"S:W
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    '************************************************************************* `Zk?.1*2/
    'Radius and conic constant of anterior lens TnKe"TA|9
    '************************************************************************* ;e[-t/SI
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 1= <Qnmw
    GetConic eID, entity, curv, conic k*n5+[U^tP
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    SetConic eID, entity, 1/Rant, CCant bF}~9WEa
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant `GSfA0?
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    '************************************************************************* (>Tu~Vo
    'Radius and conic constant of posterior lens >yL8C:J9
    '************************************************************************* .IYE"0)wJ
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ^ 5UIbA(
    GetConic eID, entity, curv, conic +1cK (Si
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    SetConic eID, entity, 1/Rpost, CCpost fYH%vr)
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost WJg?R^
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    '************************************************************************* l9SbuT$U
    'Lens thickness (Position of posterior lens surface) (IEtjv}D
    '************************************************************************* ,I)/ V>u
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2>UyA.m0
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    ' Delete any z-shift(s) FfP Ce5)
    count = 0 gE:qMs;
    While GetOperationCount(eID)>count ^(a%B
        GetOperation eID, count, op j[c|np4k\
        If op.Type="ShiftZ" Then cl{;%4$9
            DeleteOperation eID,count )WBTqML[
            count=count-1 q,+d\-+
        End If y&SueU=
        count=count+1 CRS/qso[Q'
    Wend y=q\1~]Z
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    'Set new z-shift G#K=n
    op.Type = "ShiftZ" eyUo67'7
    op.val1 = tlens xy[R9_V
    op.parent = parID o,u-%
    AddOperation eID, op $%sOL( r
    Print "Set lens thickness = " & tlens CxwZ$0
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    '************************************************************************* Nno*X9>~
    'Lens index of refraction L%N|8P[
    '************************************************************************* Au:Q4x.
    eID = FindMaterial( "Lens" ) A<AZs~f
    GetModelMaterial eID, mat up`!r;5-
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    mat.Nd = nlens M"5,8Q`PkI
    SetModelMaterial eID, mat Ga$+x++'*
    Print "Set lens index of refraction = " & nlens /1g_Uv;
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    '************************************************************************* ,GGr@})
    'Pupil diameter MSsboSxA
    '************************************************************************* aQw?r
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) i!jxjP
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    'Adjust pupil diameter (trimming volume inner hole) Qnph?t>
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" EubF`w$KWX
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    ' Adjust pupil location to just in front of the lens leX&py
    parID = FindFullName( "Geometry.Arizona Eye" ) jj.iW@m
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) X>=`{JS1
    count = 0 #(T
    While GetOperationCount(eID)>count ~[isR|>
        GetOperation eID, count, op i5q VQo
        If op.Type="ShiftZ" Then (q"Nt_y
            DeleteOperation eID,count 8`kK)iCq
            count=count-1 i\2~yXw\
        End If vG69z&
        count=count+1 R/xeC [r
    Wend F3i+t+Jt
    op.Type = "ShiftZ" V-Oy<
    op.val1 = taq-0.01 PiP\T.XANa
    op.parent = parID uI!rJc>TX
    AddOperation eID, op =gw'MA
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    Print "Set pupil diameter = " & pupilDiam Bc`jkO.q
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    'Update AZ Eye subassembly Description ehV`@ss
    eID = FindFullName( "Geometry.Arizona Eye" ) #\_N-bVu
    GetEntity eID, entity .B+R+2uY3
    entity.Description = "Accommodation = " & A & "D" >/Gz*.
    SetEntity eID, entity 6DD"Asi+
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    Update /Z94<}C6b
    Print "DONE!" MOKg[j
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End Sub Cq(dj^/~m
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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： =rMT1
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Accommodation = 4 Diopters 4siNY4i"
Pupil Diameter = 4 mm -1;BwlL
Set aqueous humor thickness = 2.81 ^y]CHr
Set anterior lens radius = 10.4 and conic constant = -2.375869 @7e h/|Y,
Set posterior lens radius = -4.424557 and conic constant = -3.081019 P4-`<i]!S
Set lens thickness = 3.927 }K!}6?17T
Set lens index of refraction = 1.42672 NTkGLD1e.
Set pupil diameter = 4 ]Nz~4ebB
DONE!
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