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2016-02-24 12:53 |
FRED运用:Arizona眼睛模型
简介 o|zrD~&$ 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。 `@ VM<av 8MYLXW6 模型 UE}8Rkt 1 2%z3/i 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。 {[YqGv=fF yv6Zo0s<J
Table 1. AZ眼睛模型的定义 [attachment=67931] F[o+p|nF 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. v#FJ+ `'A(`. CL 光源 q\\8b{~ ~#HH;q_7m 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。 kxr6sO~ doxdRYKL T:w2
[attachment=67932] 图1. 光源和提示信息使用 lOWB^uS% 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。 Q2_WH)J 3 =hZ&66 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。 -z>Z0viA ^rxfNcU7
[attachment=67933] 图2. 字母F光源的设定方法光 UY }9 Li c{'w&
[attachment=67934] 图3. 字母F在视网膜上位置点列图 K4h-4Qbn 视网膜的散射 z$I[kR%I{ =,/A\F 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。 q:EzKrE 6ywnyh h=iA;B^>
[attachment=67935] 图4. 视网膜朗伯散射设定 R"9oMaY 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。 ,N))=/ <ZHY3
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[attachment=67936] 图5. 视网膜重点采样规格设定 Hm.&f2|( 脚本 "2vNkO## )DklOEO 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: $,z[XM&9) I9Edw]
[attachment=67937] 图6. 用户对话框的创建与编辑 [pRVZV
[attachment=67938] 图7. 用户对话框编辑器 3;t@KuQ66 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 ?C#F?N0 余下的脚本计算与屈光度有关的所有参数。 N$ qNe'b n}ZBU5_ 分析 \U<F\i @2%VU#!m 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 \ eyQo>( :)
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[attachment=67939] 图7. 字母F在视网膜上颜色分析 k #,Gfs 脚本代码 )=,9`+Zta 4? /ot;>2 Option Explicit 'Remove this to enable non-dimensioned variables to be used. &Gy'AUz- FgHB1x4; Dim entity As T_ENTITY x jP" 'yU Dim op As T_OPERATION 9`gGsC Dim mat As T_MODELMATERIAL 0%&fUz36E6 Dim A As Double %xbz&'W, Dim pupilDiam As Double =?I1V#. Dim eID As Long KH@) +Rj Dim parID As Long yoA*\V Dim count As Integer &]"_pc/>m Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double qu#@F\gX Dim tlens As Double, nlens As Double F|n$0vQ* Dim curv As Double, conic As Double *~t$k56 Dim ok As Long Z>MJ0J76] Ph!KL\ Sub Main ]Xkc0E1 H/v37%p7 '用户输入对话框 &:cTo(C' Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 vCU&yXGl TextBox 220,21,40,21,.TextBox1 'default: 0 6_`eTL=G Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 1!v >I"] OKButton 40,91,90,21 ]B[/sqf CancelButton 190,91,90,21 ^&G O4u Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 wJ]$'c3 TextBox 220,49,40,21,.TextBox2 'default: 4 L[[H\ End Dialog ~i_R%z:y Dim dlg As UserDialog [(e`b WX[dM
}L ok = Dialog (dlg) -)->Jx:{ ReGO9} If ok=0 Then 'cancel button was pressed o y%g{,V Print "Execution cancelled." H@&"M% End k}Clq;G End If +IOKE\,Y Dk{nOvZu< 'Assign accommodation and pupil diameter & use defaults if field left empty *i]Z= If dlg.TextBox1 = "" Then :EldP,s#x% A = 0 'Default accommodation WG[0$j Else k f K"i A = CDbl(dlg.TextBox1) 3Ns:O2| End If lj}1'K@M )*L?PT If dlg.TextBox2 = "" Then ~pBxFA pupilDiam = 4 'Default pupil diameter s7)# NT2 Else [ Xo
J7 pupilDiam = CDbl(dlg.TextBox2) 5A=xF j{ End If |sZ9/G7 ])ZJ1QL1 Print " " HIp {< M3 Print "Accommodation = " & A & " Diopters" LM`tNZ1Fc! Print "Pupil Diameter = " & pupilDiam & " mm" K
v># U -^S<H ' Calculate new parameters with accommodation #(Yb
lY taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ,vY
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O W,oV$ s^ Rant = 12.0 - 0.4*A 'Radius of anterior lens 1p5q}">z CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ah@GSu;7 >8HRnCyp/ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens FUv)<rK CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens c$Nl-?W _q!ck0_ tlens = 3.767 + 0.04*A 'Lens thickness 0PX@E-n H-y-7PW*~ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction f*H}eu3/j Z.Y8 z#[xg 'Adjust parameters to account for accommodation sVl:EVv E6IL,Iq9 '************************************************************************* 1~iBzPU2 'Aqueous thickness (Position of Lens) BOcEL%+ '************************************************************************* 2!& ;ZcT, eID = FindFullName( "Geometry.Arizona Eye.Lens" ) `fE:5y GetCustomElement eID, entity M(f*hOG{Y r3lr`s` parID = FindFullName( "Geometry.Arizona Eye" ) 2OOj8JS gmH0-W)= ' Delete any shift(s) in z JG+o~tQC count = 0 [8g\pPQ While GetOperationCount(eID)>count ZFw743G GetOperation eID, count, op YO4ppL~xe If op.Type="ShiftZ" Then KE1@z] DeleteOperation eID,count 9 u89P count=count-1 )$.9WlQ End If G!lykk] count=count+1 7.'j~hJL Wend )W7H{# BHBR_7 'Set new shift in o~N-x* op.Type = "ShiftZ" F>{uB!!L4 op.val1 = taq |&*rSp2iH op.parent = parID .:Xe* Q AddOperation eID, op uPD_s[ Print "Set aqueous humor thickness = " & taq-0.55 VFp)`+8 9CSz<[ '************************************************************************* \FX3=WW 'Radius and conic constant of anterior lens \DdVMn '************************************************************************* Ppn ZlGQ6 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ag4^y& GetConic eID, entity, curv, conic 'n`$c{N<tM m`6`a|Twp$ SetConic eID, entity, 1/Rant, CCant )u:8Pv Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant m/c~2?-; _C\
d^a( '************************************************************************* : .eS| 'Radius and conic constant of posterior lens D#(Pg '************************************************************************* ,$*klod eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) #.K&]OV/88 GetConic eID, entity, curv, conic C8SNSeg BbhdGFG1 SetConic eID, entity, 1/Rpost, CCpost
c'4 \F9 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost J)~=b_'< XX;%:?n '************************************************************************* RLr-xg$K-t 'Lens thickness (Position of posterior lens surface) r!=VV!XZ '************************************************************************* _dY}86{ 2 z l parID = FindFullName( "Geometry.Arizona Eye.Lens" ) X*;p;N <AXYqH7%A ' Delete any z-shift(s) [IW7]Fv<F count = 0 ZuON@ ( While GetOperationCount(eID)>count 7E]l=Z`x GetOperation eID, count, op 5rhdm?Ls0 If op.Type="ShiftZ" Then L3Iz]D3s DeleteOperation eID,count ucO]&'hu: count=count-1 =z dti'2{4 End If MYm6C;o$ count=count+1 vdM\scO: Wend ~nlY8B( Yf9L~K 'Set new z-shift >l[N]CQ op.Type = "ShiftZ" n[7zK'%Dxg op.val1 = tlens z[Qv}pv op.parent = parID ;bbEd' AddOperation eID, op r-uIFhV^ Print "Set lens thickness = " & tlens mI18A#[ 3 a+Nd%hoe '************************************************************************* [!$>:_Vq/ 'Lens index of refraction UJ&,9}L8 '*************************************************************************
p5hP}Z4r eID = FindMaterial( "Lens" ) 8t"DQ Y-R GetModelMaterial eID, mat we?#)9Q< O*7~t17 mat.Nd = nlens 2HNS|GHb& SetModelMaterial eID, mat :zoX
Xo Print "Set lens index of refraction = " & nlens }9dgm[C[b wm4e:& '************************************************************************* C\[UAxZ3X 'Pupil diameter ' ga2C\) '************************************************************************* S]a$w5ZP eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) bL%)k61G_v `VbG%y&I 'Adjust pupil diameter (trimming volume inner hole) _Fjv.VQ, lX7^LB SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ^m9cEl^:nQ AJ}Q,E ' Adjust pupil location to just in front of the lens )}v2Z3: parID = FindFullName( "Geometry.Arizona Eye" ) +d96Z^KUhv eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) VP&lWPA}\$ count = 0 /cn_|DwN5 While GetOperationCount(eID)>count ??;[`_h{bz GetOperation eID, count, op Z5K,y19/~ If op.Type="ShiftZ" Then j.*}W4`Q_ DeleteOperation eID,count y.2 SHn0 count=count-1 8Sa<I.l End If (@9-"W count=count+1 j7zQ&ANF Wend AnQRSB ( op.Type = "ShiftZ" .#}R$}e+ op.val1 = taq-0.01 'UKB
pm/ op.parent = parID {s]eXc]K} AddOperation eID, op t/w>t! q }^t?v*kcA Print "Set pupil diameter = " & pupilDiam g=wnly >?tpGEZ\ 'Update AZ Eye subassembly Description l0f6L xfz eID = FindFullName( "Geometry.Arizona Eye" ) #kA+Yqy\) GetEntity eID, entity Y`v&YcX; entity.Description = "Accommodation = " & A & "D" 3ly|y{M", SetEntity eID, entity ~}fpe>M: li?Gb1 Update KAGq\7 Print "DONE!" <ZLs+|1 Bb6_['y End Sub O B:G5B` &%<G2x$ 如果屈光度是4,光瞳直径是4,则会输出如下数据: U.\kAEJ Z3Y%VHB_F( Accommodation = 4 Diopters *!r8HV/< Pupil Diameter = 4 mm xfilxd Set aqueous humor thickness = 2.81 tfO
_b5g Set anterior lens radius = 10.4 and conic constant = -2.375869 :HC{6W`$ Set posterior lens radius = -4.424557 and conic constant = -3.081019 8oK30? Set lens thickness = 3.927
Y|",.~ Set lens index of refraction = 1.42672 OWU]gh@r Set pupil diameter = 4 JkTL+obu DONE! 8@!SM 2B|3`trY4x
(文章来源:讯技光电)
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