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2016-02-24 12:53 |
FRED运用:Arizona眼睛模型
简介 B2vh-%63 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。 ^$jb7HMObI a 7V-C 模型 :K,i\ ;u
({\K 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 8U"v6S~A%Q H [\o RId
Table 1. AZ眼睛模型的定义 [attachment=67931] :gibfk]C 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. 9!\B6=r y4 r.&Vw|*> 光源 ? pmHFlx <8&au(I,vB 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 N0Lw}@p 9d659iC Xza(k
[attachment=67932] 图1. 光源和提示信息使用 7hcYD!DS 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 *I.f1lz%* %3-y[f 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 zT]8KA s?}e^/"v
[attachment=67933] 图2. 字母F光源的设定方法光 dt]-,Y
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[attachment=67934] 图3. 字母F在视网膜上位置点列图 Qx#"q '2 视网膜的散射 &i6mW8l &)ChQZA 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 n5NsmVW \x E7UU {rw|# Z>A
[attachment=67935] 图4. 视网膜朗伯散射设定 !9r$e99R 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。 `iNSr?N. dn+KH+v _C?hHWSf"
[attachment=67936] 图5. 视网膜重点采样规格设定 xJ8M6O8 脚本 n
M*%o- =s2*H8] 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: ,!y$qVg'\f KwSqKI7]0
[attachment=67937] 图6. 用户对话框的创建与编辑 "ne?P9'hF
[attachment=67938] 图7. 用户对话框编辑器 -;m0R 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 1};Stai'
余下的脚本计算与屈光度有关的所有参数。 ,T$U'&; BM
.~ 5\ 分析 24*XL, WiR(;m<g 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ChPmX+.i_ IY\5@PVZ
[attachment=67939] 图7. 字母F在视网膜上颜色分析 <uw9DU7G 脚本代码 ]MitOkX [!#L6&:a8 Option Explicit 'Remove this to enable non-dimensioned variables to be used. .jE{ 3^ Hk.TM2{w Dim entity As T_ENTITY /]Md~=yNp Dim op As T_OPERATION &.Qrs:U Dim mat As T_MODELMATERIAL Yu^4VXp~M% Dim A As Double qiBVGH Dim pupilDiam As Double @9RM9zK.q Dim eID As Long 6}Ci>_i4# Dim parID As Long ,Uqs1#r Dim count As Integer ?X<eV1a Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double nT$SfGFj8 Dim tlens As Double, nlens As Double H3=qe I Dim curv As Double, conic As Double A[{yCn`tM Dim ok As Long 'yEHI #gs`#6 ,' Sub Main D.u{~ 0-Ku7<a '用户输入对话框 _|I#{jK Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Flm%T-Dl TextBox 220,21,40,21,.TextBox1 'default: 0 2-v%`fA Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |3"KK OKButton 40,91,90,21 %pL''R9VF CancelButton 190,91,90,21 )}Kf= Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 qt"m TextBox 220,49,40,21,.TextBox2 'default: 4 wE`]7mA End Dialog p]+Pkxz]' Dim dlg As UserDialog "`e{/7I Fq<A ok = Dialog (dlg) I-(zaqp@ v$wIm, j If ok=0 Then 'cancel button was pressed qqY"*uJ' Print "Execution cancelled." Wt-GjxGi End `d`T*_ End If 3bH'H*2 K
Z91- 'Assign accommodation and pupil diameter & use defaults if field left empty !z3jTv If dlg.TextBox1 = "" Then ZKTz
, A = 0 'Default accommodation E*K;H8}s Else
dkTX A = CDbl(dlg.TextBox1) -C]5>& W End If }|NCboM^_ bK&+5t& If dlg.TextBox2 = "" Then r[iflBP pupilDiam = 4 'Default pupil diameter 5Yq@;e Else {cVEmvE8 pupilDiam = CDbl(dlg.TextBox2) `b7t4d* End If +iRh {_p_%; Print " " meO:@Z0 Print "Accommodation = " & A & " Diopters" 7~.9=I'A Print "Pupil Diameter = " & pupilDiam & " mm" ;iL#7NG-R W.KDVE$}f ' Calculate new parameters with accommodation F{;((VboN taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness RMu~l@ 'I6i,+D/q Rant = 12.0 - 0.4*A 'Radius of anterior lens y}ev ,j CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens g*C7
' m~0/&RA Rpost = -5.224557 + 0.2*A 'Radius of posterior lens `Eo.v#< CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens w%jII{@, 00~mOK;1 tlens = 3.767 + 0.04*A 'Lens thickness ^8N}9a [/41%B2 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 56kI
5: S3Xl 'Adjust parameters to account for accommodation @<EO`L)Z sWnLEw '*************************************************************************
S9FE 'Aqueous thickness (Position of Lens) k=T\\]KxC '************************************************************************* M&9+6e'-F eID = FindFullName( "Geometry.Arizona Eye.Lens" ) $}<e|3_ GetCustomElement eID, entity '!~)?C< -k"/X8 parID = FindFullName( "Geometry.Arizona Eye" ) u>a5GkG. z[qDkL ' Delete any shift(s) in z Yufc{M00 count = 0 59;KQ While GetOperationCount(eID)>count T%*D~=fQ' GetOperation eID, count, op d)Y}>@:W If op.Type="ShiftZ" Then \bvfEP DeleteOperation eID,count |[b{)s?x count=count-1 5vnrA'BhBU End If <bEbweQrgm count=count+1 ^v7gIC Wend RPL:- m#\dSl} 'Set new shift in hf&9uHN%7m op.Type = "ShiftZ" ml
}{|Yz op.val1 = taq }`m/bgtFX
op.parent = parID /R wjCUf AddOperation eID, op p>8D;#HmL Print "Set aqueous humor thickness = " & taq-0.55 LyFN.2qw _u QOHwn '************************************************************************* WX3-\Y5E 'Radius and conic constant of anterior lens 89(Q1R ?: '************************************************************************* Z=vU}S>r|v eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) =]0&i]z[. GetConic eID, entity, curv, conic !'*-$e "oO%`:pb SetConic eID, entity, 1/Rant, CCant /aZ`[m2 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant WCixKYq -m~#Bq '************************************************************************* u;2[AQ. 'Radius and conic constant of posterior lens XVZ '************************************************************************* {;6`_-As% eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) a<bwzX|. GetConic eID, entity, curv, conic u.xnO cOH! q^<?]8 SetConic eID, entity, 1/Rpost, CCpost 2`=7_v Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost v):Or'$~M H$UcF1k< '************************************************************************* NqWdRU 'Lens thickness (Position of posterior lens surface) E+;7>ja '************************************************************************* 9~[Y-cpoi 7WZ+T"O{I parID = FindFullName( "Geometry.Arizona Eye.Lens" ) &0JI!bR( f(MO_Sj] ' Delete any z-shift(s) hM@>q&q_ count = 0 [MY|T<q While GetOperationCount(eID)>count 9p(.A$ GetOperation eID, count, op .,6-u If op.Type="ShiftZ" Then vUM4S26"NT DeleteOperation eID,count Wvf
^N( count=count-1 $1`2kM5 End If '/s)%bc count=count+1 SO0PF|{\r Wend k;FUs[ *gWwALGo5 'Set new z-shift 1p=]hC op.Type = "ShiftZ" -ZLJeY L op.val1 = tlens vyI!]p op.parent = parID 97!;.f- AddOperation eID, op 8bld3p"^ Print "Set lens thickness = " & tlens U # qK. E~"y$Fqe '************************************************************************* }*]-jWt1J\ 'Lens index of refraction O:Tj"@h '************************************************************************* TOQP'/ eID = FindMaterial( "Lens" ) TuaBm1S{f GetModelMaterial eID, mat i=2N;sAl
[/8%3 mat.Nd = nlens CzrC%x y SetModelMaterial eID, mat Mb*?5R6; Print "Set lens index of refraction = " & nlens g[4WzDF* X=&KayD '************************************************************************* 13x p_j 'Pupil diameter ncT&Gr '************************************************************************* NK
H@+,+V eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) #o#H?Vo9b T]~xj4 'Adjust pupil diameter (trimming volume inner hole) QoT;WM Z LZxNAua SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" |P?*5xPB nAlQ7' ' Adjust pupil location to just in front of the lens +v:SM9 parID = FindFullName( "Geometry.Arizona Eye" ) O0H.C0} eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) FfT`;j count = 0 (TT}6j While GetOperationCount(eID)>count 5\VWC I GetOperation eID, count, op DZtsy!xA If op.Type="ShiftZ" Then a0)QH DeleteOperation eID,count 8Z=R)asGS count=count-1 ,r_Gf5c End If 5]:U9ts# count=count+1 +9sQZB# ( Wend dioGAai' op.Type = "ShiftZ" [v!f<zSQK op.val1 = taq-0.01 G$('-3@i`w op.parent = parID @-`*m+$U6 AddOperation eID, op 'PW5ux@`< W ]8QM1$ Print "Set pupil diameter = " & pupilDiam ('+d.F[109 >uEzw4w 'Update AZ Eye subassembly Description <t!W5q eID = FindFullName( "Geometry.Arizona Eye" ) h^P#{W!e\ GetEntity eID, entity YKK*ER0 entity.Description = "Accommodation = " & A & "D" Q\sK"~@3 SetEntity eID, entity ]\HvK CN} dft!lBN Update Z*6IW7# Print "DONE!" N?`' /e ;*2Cm'8E End Sub l,aay-E .O<obq~;C 如果屈光度是4,光瞳直径是4,则会输出如下数据: <qt|d& C\hM =% Accommodation = 4 Diopters &_8947 Pupil Diameter = 4 mm {R{=+2K!|k Set aqueous humor thickness = 2.81 a(ZcmYzXU Set anterior lens radius = 10.4 and conic constant = -2.375869 )%fH(ns( Set posterior lens radius = -4.424557 and conic constant = -3.081019 @_{=V0 Set lens thickness = 3.927 b"
[|:F>P Set lens index of refraction = 1.42672 HTTCTR Set pupil diameter = 4 {?7Uj DONE! %E;'ln4h&, X2'0PXv>!
(文章来源:讯技光电)
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