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2016-02-24 12:53 |
FRED运用:Arizona眼睛模型
简介 5,4m_fBoW 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。 NwxDxIIH/) {5fL!`6w 模型 gm%cAme :[CEHRc7x 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。 *U}ztH-+/ Uu52uR
Table 1. AZ眼睛模型的定义 [attachment=67931] Qm=iCZ|E^! 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. WEJ-K<A( /2
hk 9XM 光源 d"n"A?nXh ef)zf+o 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。 1*|/N}g) t-5Y,}j o@7U4#E
[attachment=67932] 图1. 光源和提示信息使用
Bnk' 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。 0qIg:+l+ f$ tm<:)Y 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。
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[attachment=67933] 图2. 字母F光源的设定方法光 i]s%tEZ1 lD, ~%
[attachment=67934] 图3. 字母F在视网膜上位置点列图 j@w1S[vt 视网膜的散射 9UVT]acq ~@)s)K 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。 $:\`E56\ @OGG]0
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[attachment=67935] 图4. 视网膜朗伯散射设定 gWoUE7.3` 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。 ,tcUJ}l Yufjy=! 9zS
[attachment=67936] 图5. 视网膜重点采样规格设定 0:>hK\F# 脚本 (Zd(?">i ~**x_ v 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: "*.N'J\ D,R',(3
[attachment=67937] 图6. 用户对话框的创建与编辑 A)V*faD
[attachment=67938] 图7. 用户对话框编辑器 9(nq 4HvI 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。 0?(uqjD: 余下的脚本计算与屈光度有关的所有参数。 oP9 y@U dq`{fqGl 分析 H1 7I"5N ]@b9m 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 EFljUT?& vV*J;%MO
[attachment=67939] 图7. 字母F在视网膜上颜色分析 dS3\P5D.*c 脚本代码 P.5l9Ns(O biU_ImJ>0 Option Explicit 'Remove this to enable non-dimensioned variables to be used. w/(c}%v}= O,|NOz Dim entity As T_ENTITY =>B"j`oR Dim op As T_OPERATION
oI[rxr Dim mat As T_MODELMATERIAL (tOhuSW Dim A As Double <R;wa@a> Dim pupilDiam As Double } `r.fD Dim eID As Long 5h`L W AB Dim parID As Long @+H0D" Dim count As Integer k&%i+5X Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double @ci..::5 Dim tlens As Double, nlens As Double K%+4M#jj5 Dim curv As Double, conic As Double VQ|{Q} Dim ok As Long 8cG`We8l& m7g*zu2# Sub Main i9XpP(mf [}j a\!P '用户输入对话框 P1T{5u!T Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7xv9v1[' TextBox 220,21,40,21,.TextBox1 'default: 0 zMu9A| Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 $b1>,d'oz OKButton 40,91,90,21 |xcC'1WU CancelButton 190,91,90,21 `Ucj_6&Tqs Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 H~nX!sO TextBox 220,49,40,21,.TextBox2 'default: 4 05T?c{ ; End Dialog VGD~) z57 Dim dlg As UserDialog t_w\k_
T 6bhb_U'f ok = Dialog (dlg) un_NBv} m^!j)\sM5 If ok=0 Then 'cancel button was pressed Se'SDJl= Print "Execution cancelled." GI/NouaNfm End x@Z{5w_a End If 1Ub=RyB Q|h$D~ 'Assign accommodation and pupil diameter & use defaults if field left empty K+!e1
' If dlg.TextBox1 = "" Then X+N5iT A = 0 'Default accommodation ].kj-,5>f Else 8`urkEI^r A = CDbl(dlg.TextBox1) *)-@'{]u B End If /~w*)e) ||QK)$" If dlg.TextBox2 = "" Then XZARy:+bc pupilDiam = 4 'Default pupil diameter aYT!xdCI Else M.t,o\xl pupilDiam = CDbl(dlg.TextBox2) 5)T[ha77u End If LX7P?j $&Vba@v Print " " m\XsU?SuX Print "Accommodation = " & A & " Diopters" {{Ox%Zm Print "Pupil Diameter = " & pupilDiam & " mm" Z/G#3-5)p jDb\4QyC ' Calculate new parameters with accommodation #J&3Zds taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness >"bW' wrgB =o Rant = 12.0 - 0.4*A 'Radius of anterior lens )~=8Ssu CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens n({%|O<| sED"}F) Rpost = -5.224557 + 0.2*A 'Radius of posterior lens zY:3*DiM CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens \]f+{d-& |{kbc0* tlens = 3.767 + 0.04*A 'Lens thickness $Bz};@ 1m"WrTen nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction >dJuk6J&c& FqA4 OU 'Adjust parameters to account for accommodation #z.n?d2Gd SgewAng?@o '************************************************************************* er7(Wph 'Aqueous thickness (Position of Lens) 27ZqdHd '************************************************************************* AJEbiP eID = FindFullName( "Geometry.Arizona Eye.Lens" ) x;yvv3-$ GetCustomElement eID, entity N s0,Z#Z+ :Q("
parID = FindFullName( "Geometry.Arizona Eye" ) ["Ts7;q9[ K*T^w3= ' Delete any shift(s) in z Q&r.wV| count = 0 ;hDk gp While GetOperationCount(eID)>count NJsaTBT GetOperation eID, count, op S!u8JG1 If op.Type="ShiftZ" Then /Z:NoTGn DeleteOperation eID,count {f-O~P<Z4 count=count-1 <DR|r End If Fnak:R0 count=count+1 <A Hzs Wend xtP:Q9!N k*N!U[] 'Set new shift in n46!H0mJ op.Type = "ShiftZ" uOzoE_i op.val1 = taq xA7~"q&u op.parent = parID PF/K&&9} AddOperation eID, op v2rO>NY4 Print "Set aqueous humor thickness = " & taq-0.55 ^PNDxtd|v a`xAk^w+ '************************************************************************* o=7,U/{D! 'Radius and conic constant of anterior lens d~~, 5E '************************************************************************* vx($o9 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) N`efLOMl]
GetConic eID, entity, curv, conic (o B4* zJy=1r SetConic eID, entity, 1/Rant, CCant 8k-]u3 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant E& 6I`8 [nig^8 '************************************************************************* ?lD)J?j 'Radius and conic constant of posterior lens .o`Io[io '************************************************************************* [yN+(^i eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) \_,p@r]Q GetConic eID, entity, curv, conic /J-'[Mc'D[ >Vt2@Ee SetConic eID, entity, 1/Rpost, CCpost [A =0fg5 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 1}la)lC 3E;@.jD '************************************************************************* !i-t6f 'Lens thickness (Position of posterior lens surface) B@M9oNWHu '************************************************************************* ~;CNWJtcf( -}UY2) parID = FindFullName( "Geometry.Arizona Eye.Lens" ) _-({MX[3k< >R]M:Wx ' Delete any z-shift(s) 082iEG count = 0 eg/itty While GetOperationCount(eID)>count #fa,}aj GetOperation eID, count, op b]z_2h~` If op.Type="ShiftZ" Then R]%"YQ V DeleteOperation eID,count 03 gbcNo count=count-1 %r1#G.2YW End If YRVh[Bqg` count=count+1 $Ah
p4oiE Wend :lo5,B;k @-[}pZ/ 'Set new z-shift FCNYfjB% op.Type = "ShiftZ" Lp:VU-S op.val1 = tlens %]I#]jR op.parent = parID 7d>w]R,Z AddOperation eID, op W;I{4ed6 Print "Set lens thickness = " & tlens ^L$`)Ja 1z7+:~;l '************************************************************************* N 5Om~D 'Lens index of refraction EF:ec9 . '************************************************************************* ;iX~3[] eID = FindMaterial( "Lens" ) {7m2vv? Z GetModelMaterial eID, mat C8|Ls(4Ck xwZ1Q,'C mat.Nd = nlens id9QfJ9t SetModelMaterial eID, mat ")MHP~ ? Print "Set lens index of refraction = " & nlens *O'|NQhNx> T2Z$*;,>T '*************************************************************************
:'Gn?dv| 'Pupil diameter y%%VJ}'X! '************************************************************************* 3>VL>;75[ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) (Z$7;OAI 5B:"$vC{= 'Adjust pupil diameter (trimming volume inner hole) #sCR} 4_-&PZ,d SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 3_
J'+ x`7Le&4f ' Adjust pupil location to just in front of the lens uxL+oP0 parID = FindFullName( "Geometry.Arizona Eye" ) D+uo gRS61 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) W'@G5e count = 0 " J9 While GetOperationCount(eID)>count \wz^Z{U GetOperation eID, count, op xL_QTj If op.Type="ShiftZ" Then P<R^eLZ<& DeleteOperation eID,count =I'iD0eR count=count-1 IIY_Q9in End If Y<W9LF count=count+1 #g$I>\O< Wend W gyRK2#! op.Type = "ShiftZ" @Un/,-ck op.val1 = taq-0.01 d4IQ;u op.parent = parID 2i6=g< AddOperation eID, op vT{(7m!Ra *3Lo[GE> Print "Set pupil diameter = " & pupilDiam !U@ETo c$[2tZ 'Update AZ Eye subassembly Description >b\|%=(x!* eID = FindFullName( "Geometry.Arizona Eye" ) A7YCSjB GetEntity eID, entity Ynf "g#( entity.Description = "Accommodation = " & A & "D" fsOlg9 SetEntity eID, entity *<cRQfA1
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P@$< Update 4S4MQ Print "DONE!" prS%lg>
=AaF$R End Sub yj_/:eX KF
*F 如果屈光度是4,光瞳直径是4,则会输出如下数据: PYi<iSr M)K!!Jqh Accommodation = 4 Diopters Vr1r2G2 Pupil Diameter = 4 mm a+z>pV| Set aqueous humor thickness = 2.81 r:o9:w: Set anterior lens radius = 10.4 and conic constant = -2.375869 h/C{ Set posterior lens radius = -4.424557 and conic constant = -3.081019 oNXYBeu+ Set lens thickness = 3.927 C\"C12n{ Set lens index of refraction = 1.42672 Oq<3&* Set pupil diameter = 4 n,2 p)#? DONE! [4qvQ7Y
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(文章来源:讯技光电)
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