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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。 iDDJJ>F26
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模型 obvE m[x!Z
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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。 @1o X&#
Table 1. AZ眼睛模型的定义 s" ,Ea*
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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. J|I*n
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光源 8 -<F4^i_i
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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。 [3X\"x5@V
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图1. 光源和提示信息使用 My>q%lF=fw
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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。 ;87PP7~
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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。 qIJc\,'
图2. 字母F光源的设定方法光 i@9
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图3. 字母F在视网膜上位置点列图 W/UA%We3+L
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视网膜的散射 %fg 6', 2
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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。 .'=S1|_(
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图4. 视网膜朗伯散射设定 )<HvIr(xr
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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。 d*|RFU
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图5. 视网膜重点采样规格设定 K{d3)lVYCS
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脚本 -,/7u 3
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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： lq.:/_m0
图6. 用户对话框的创建与编辑 hwM<0Jf
图7. 用户对话框编辑器 "81'{\(I_
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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。 *m]Y6
余下的脚本计算与屈光度有关的所有参数。 0y$VPg sKf
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分析 x"Ll/E)\v]
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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。 oQ,n?on
图7. 字母F在视网膜上颜色分析 B{\Y~>]Pj
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脚本代码 >h%>s4W
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Option Explicit 'Remove this to enable non-dimensioned variables to be used. Rng-o!
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Dim entity As T_ENTITY Vsi:O7|+
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Dim op As T_OPERATION 3F"vK
Dim mat As T_MODELMATERIAL n`^jNXE
Dim A As Double Xj]9/? B?
Dim pupilDiam As Double NUM!'+H_h
Dim eID As Long (P? |Bk [
Dim parID As Long :sw5@JdJ
Dim count As Integer *i*\ dl
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ~hq\XQX
Dim tlens As Double, nlens As Double >&HW6 c
Dim curv As Double, conic As Double d s`YVXKH
Dim ok As Long vFHeGq70j
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Sub Main Z5'^ H j1,
nZ =[6?
'用户输入对话框 28v^j*=*
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Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _t,aPowX
TextBox 220,21,40,21,.TextBox1 'default: 0 Ru
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Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 "{@[ 06|1
OKButton 40,91,90,21 &p#PYs|H
CancelButton 190,91,90,21 Ag T)J
Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 , L
TextBox 220,49,40,21,.TextBox2 'default: 4 k T
End Dialog Z[[*:9rY|
Dim dlg As UserDialog pGU .+[|(
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ok = Dialog (dlg) bX[ZVE(L
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If ok=0 Then 'cancel button was pressed %w l:>9]
Print "Execution cancelled." #3Z AMV
End w)J-e gc
End If "E7<S5 cr
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'Assign accommodation and pupil diameter & use defaults if field left empty kReZch}
If dlg.TextBox1 = "" Then W`LG.`JW
A = 0 'Default accommodation c^"4 l
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Else prM)t8SE
A = CDbl(dlg.TextBox1) M&=SvM.f
End If 0-OKbw5%=b
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If dlg.TextBox2 = "" Then ~9rNP{+
pupilDiam = 4 'Default pupil diameter kqX % y
Else #Qg)4[pMJ
pupilDiam = CDbl(dlg.TextBox2) U5ph4G
End If k ]gPMhe
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Print " " w)K547!00
Print "Accommodation = " & A & " Diopters" XU<ow k
Print "Pupil Diameter = " & pupilDiam & " mm" UazK0{t<f
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' Calculate new parameters with accommodation ,c&t#mu *0
taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness U*N{H$ACuR
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Rant = 12.0 - 0.4*A 'Radius of anterior lens <%^WZ:c
CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens
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Rpost = -5.224557 + 0.2*A 'Radius of posterior lens b! MN QGs
CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Q u/f>tJN;
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tlens = 3.767 + 0.04*A 'Lens thickness = MJRQ V67
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nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction VJA/d2Oys
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'Adjust parameters to account for accommodation H! FaI(YZl
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'************************************************************************* b&,Z mDJh
'Aqueous thickness (Position of Lens) a{^ 2c!
'************************************************************************* &RuTq6)r
eID = FindFullName( "Geometry.Arizona Eye.Lens" ) +MY rNR.p
GetCustomElement eID, entity 08AD~^^
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parID = FindFullName( "Geometry.Arizona Eye" ) 1foG*
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' Delete any shift(s) in z }#~E-N3x
count = 0 !:xE
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While GetOperationCount(eID)>count uZ f
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GetOperation eID, count, op %c$|.TkX
If op.Type="ShiftZ" Then OP= oSfa
DeleteOperation eID,count V"gKk$j7
count=count-1 mo
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End If c #?~1@=
count=count+1 ]p4?nT@]
Wend ,. ht ~AE
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'Set new shift in $B9?>a| {A
op.Type = "ShiftZ" @b2?BSdUp
op.val1 = taq S H"<f_
op.parent = parID KDf#e3
AddOperation eID, op [# X} (
Print "Set aqueous humor thickness = " & taq-0.55 "`S?q G
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'************************************************************************* qxyY2&
'Radius and conic constant of anterior lens y_ Gs _xg
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eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ME)='~E
GetConic eID, entity, curv, conic 4S+E% b|)
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SetConic eID, entity, 1/Rant, CCant g@t..xJ,
Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant MkdC*|
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'************************************************************************* P xWH)4
'Radius and conic constant of posterior lens l ~xXy<
'************************************************************************* 2A*,9S|Y
eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) G&Yo2aADR
GetConic eID, entity, curv, conic '%+LQ"Bp
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SetConic eID, entity, 1/Rpost, CCpost V%t_,AT
Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost TR
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'************************************************************************* xrlyph5mE
'Lens thickness (Position of posterior lens surface) Mu.oqT
'************************************************************************* <Nloh+n=
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parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 1n*"C!q
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' Delete any z-shift(s) c8_,S[W
count = 0 g C%$)4-:
While GetOperationCount(eID)>count P3a]*> .,
GetOperation eID, count, op U3M; {_g
If op.Type="ShiftZ" Then 2>J;P C[;
DeleteOperation eID,count
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count=count-1 8A*tpMV?J
End If LF (S"Of
count=count+1 "cOBEhn%l
Wend 6%o@!|=I
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'Set new z-shift 5YUe>P D
op.Type = "ShiftZ" bx7hQzoX=b
op.val1 = tlens W=#jtU`:5
op.parent = parID r' |ei ,
AddOperation eID, op az}zoFl
Print "Set lens thickness = " & tlens C(KV5c
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'************************************************************************* A-^B ?E
'Lens index of refraction uc=u4@.>
'************************************************************************* AXo)(\
eID = FindMaterial( "Lens" ) q}E'x/s2m
GetModelMaterial eID, mat AGx(IK/_
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mat.Nd = nlens FELW?Q?k
SetModelMaterial eID, mat )"00fZL
Print "Set lens index of refraction = " & nlens 11!4#z6w
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'************************************************************************* ZxDh! _[s
'Pupil diameter <BdC#t:*L
'************************************************************************* Idj Z2)$
eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Mu$ q) u
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'Adjust pupil diameter (trimming volume inner hole) JmBMc }54
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SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 3m~3l d
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' Adjust pupil location to just in front of the lens [H2su|rBI`
parID = FindFullName( "Geometry.Arizona Eye" ) )R@Y$*fm
eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) y7z ,I
count = 0 1bCS4fs^>
While GetOperationCount(eID)>count \x_$Pu
GetOperation eID, count, op v=IcVHuf
If op.Type="ShiftZ" Then $7Tj<;TV
DeleteOperation eID,count Xs2B:`,hh
count=count-1 |c2;`T#`o
End If +: J:S"G
count=count+1 b#S-u }1PE
Wend `K2vG`c
op.Type = "ShiftZ" a
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op.val1 = taq-0.01 %VrMlG4hx
op.parent = parID #hEU)G' $+
AddOperation eID, op Y~ OyoNu2
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Print "Set pupil diameter = " & pupilDiam D6P/39}W
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'Update AZ Eye subassembly Description c[?&;# feV
eID = FindFullName( "Geometry.Arizona Eye" ) fa/p
GetEntity eID, entity EOGz;:b&
entity.Description = "Accommodation = " & A & "D" =m xj2>,&
SetEntity eID, entity r+MqjdXG
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Update d^|r#" o[
Print "DONE!" H|cxy?iJ
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End Sub &([Gc+"5E.
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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： &KeD{M%
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Accommodation = 4 Diopters S|B S;VY
Pupil Diameter = 4 mm NV3oJ0f&2
Set aqueous humor thickness = 2.81 :-b-)*TC;
Set anterior lens radius = 10.4 and conic constant = -2.375869 9kas]zQ%=P
Set posterior lens radius = -4.424557 and conic constant = -3.081019 GS! 1K( 7
Set lens thickness = 3.927 35SL*zS@-
Set lens index of refraction = 1.42672 3,@|kN<
Set pupil diameter = 4 DJH,#re>
DONE! |
