FRED运用:Arizona眼睛模型
简介 gk?H@b* 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。
F{Yr8(UHA UeZ(@6_: 模型 AsuugcN* tg 'g R 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。 jxm#4 kxEq_FX
Table 1. AZ眼睛模型的定义 [attachment=67931] XHKLl?- 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. %rrD+ >+;}"J 光源 KTmwkZcfYD Uea2WJpX 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。 [X]hb7-&
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[attachment=67932] 图1. 光源和提示信息使用 dD39?K/ 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。 jz;{,F >f^kp8`3{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。 m;xa}b{(i A-L)2.M
[attachment=67933] 图2. 字母F光源的设定方法光 seAEv0YWz )
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[attachment=67934] 图3. 字母F在视网膜上位置点列图 FxK!h.C. 视网膜的散射 e&ZH 1^O #pW!(tfN^a 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。 go6;_ e8:O2!HW `S?_=JIX
[attachment=67935] 图4. 视网膜朗伯散射设定 QALr 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。 T 8]*bw ir\)Hz2P ]xb2W~
[attachment=67936] 图5. 视网膜重点采样规格设定 $Fc}K+ 脚本 9)=bBQyr: KdZ=g ZSH 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: NgsEEPu? yD!GgnW
[attachment=67937] 图6. 用户对话框的创建与编辑 vg X7B4
[attachment=67938] 图7. 用户对话框编辑器 `{yI|
Wf 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。 mrKIiaU<J 余下的脚本计算与屈光度有关的所有参数。
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分析 8~.8"gQ >bhF{*t#;y 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 &IDT[J {A
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[attachment=67939] 图7. 字母F在视网膜上颜色分析 &E!m(|6?+ 脚本代码 5=9Eb 5BLBcw\; Option Explicit 'Remove this to enable non-dimensioned variables to be used. gth_Sz5!# `)w=@9B)" Dim entity As T_ENTITY '< >Q20 Dim op As T_OPERATION )`W|J%w+ Dim mat As T_MODELMATERIAL =)iAU/*N Dim A As Double +Qzl-eN/+ Dim pupilDiam As Double 4v5qK Dim eID As Long Sc}Rs Dim parID As Long /=#~8 Dim count As Integer e&[~}f? Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double |L}tAS`8 Dim tlens As Double, nlens As Double |VyN>&r~6 Dim curv As Double, conic As Double i"DyXIrk2 Dim ok As Long 6y?uH;SL D^];6\=.i Sub Main :y{@=E=XSC 37tJ6R6[ '用户输入对话框 .]<iRf[\[ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 N0K <zxR TextBox 220,21,40,21,.TextBox1 'default: 0 `tKs|GQf Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ]D2d=\ OKButton 40,91,90,21 pA@R,O>zr CancelButton 190,91,90,21 ,CqGO %DY Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 dIQ3snG TextBox 220,49,40,21,.TextBox2 'default: 4 awQB0ow'$P End Dialog z<yqQ[ Dim dlg As UserDialog v`7~#Avhz (X2[}K ok = Dialog (dlg) k#V\O2lb =XSupM[T If ok=0 Then 'cancel button was pressed dd6l+z Print "Execution cancelled." Rp_ }_hL0 End 4~ nf~ End If Tz\v.&? $ 1^WkW\9kO 'Assign accommodation and pupil diameter & use defaults if field left empty !L)|N< If dlg.TextBox1 = "" Then rC/z8m3z A = 0 'Default accommodation ]yFO~4Nu Else (ze9-!% A = CDbl(dlg.TextBox1) 5GJa+St? End If wwa)VgoS[ ^O"o-3dte If dlg.TextBox2 = "" Then pYUQSsqC pupilDiam = 4 'Default pupil diameter g+4x Else {HVsRpNEf pupilDiam = CDbl(dlg.TextBox2) HMKogGTTo End If S[&yO-=p6 b'`C<Rk Print " " S1i~r+jf Print "Accommodation = " & A & " Diopters" ,x[~|J! Print "Pupil Diameter = " & pupilDiam & " mm" m^tf=O< #Qu|9Q[QH ' Calculate new parameters with accommodation QbWeQ[V{ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness (~PT(B? ~Hb0)M@y7 Rant = 12.0 - 0.4*A 'Radius of anterior lens PnI_W84z CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens p%\&M bA h4~VzCR4x\ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens OZ<fQf.Gh} CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ,A0v 5Q< 9}G<\y tlens = 3.767 + 0.04*A 'Lens thickness [bBPs&7u `n`HwDo;i nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ]99;7 ORIXcj] 'Adjust parameters to account for accommodation 7;sF0oB5e i)]^b{5nyB '************************************************************************* EPEn"{;U 'Aqueous thickness (Position of Lens) \LM{.gzT '************************************************************************* ?y~"\iP eID = FindFullName( "Geometry.Arizona Eye.Lens" ) f Q2U| GetCustomElement eID, entity &w^:nVgl 0(A&m , parID = FindFullName( "Geometry.Arizona Eye" ) x^ Y sXzu (~#-J7 ' Delete any shift(s) in z aSfAu!j) count = 0 gJOD+~ While GetOperationCount(eID)>count u&o<>d;) GetOperation eID, count, op
X;dUlSi If op.Type="ShiftZ" Then ~=$d>ZNQ DeleteOperation eID,count (^)(#CxO count=count-1 msZ3%L End If i6:O9Km count=count+1 qI2&a$Zb$ Wend *adwCiB N8{
8 a 'Set new shift in mP./e8 op.Type = "ShiftZ" l+^4y_ op.val1 = taq ebf/cCh op.parent = parID D.w6/DxaXa AddOperation eID, op
A4TW`g_zm Print "Set aqueous humor thickness = " & taq-0.55 >ZnnGX6$( %? O$xQ.< '************************************************************************* KzZRFEA_ 'Radius and conic constant of anterior lens 6dqI{T-i? '************************************************************************* OT3~5j1[ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) [T2!,D. GetConic eID, entity, curv, conic AK$i0Rn;pm AaDMX, SetConic eID, entity, 1/Rant, CCant (U|WP%IM' Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Lr(My3vF8q 1Zgv+. '************************************************************************* ;fm>
\f 'Radius and conic constant of posterior lens FOSC#W9E '************************************************************************* :io[9B [ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) zIc_'Z,b GetConic eID, entity, curv, conic |k/;1.b!9( VO7&<Y}{x SetConic eID, entity, 1/Rpost, CCpost ,y[w`Q\ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost O
_^Y*! AXPdgo6 '************************************************************************* XlxM.;i0H 'Lens thickness (Position of posterior lens surface) Xcc i)",! '************************************************************************* zQsW*)L a )M3t parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ~PedR=Y0n eY'RDQa ' Delete any z-shift(s) <*db%{ count = 0 R"O,2+@<. While GetOperationCount(eID)>count +-MieiKv GetOperation eID, count, op q.d
qr< If op.Type="ShiftZ" Then n6#z{,W<3 DeleteOperation eID,count )3)fq:[ count=count-1 1<pb=H End If
y7.oy" count=count+1 dwUs[v Wend o65I(` ?q}:ojrs1 'Set new z-shift X/A(8rvCr op.Type = "ShiftZ" I\$?'q> op.val1 = tlens 'F Cmbry op.parent = parID x8RiYi+ AddOperation eID, op Q^Q6|
n Print "Set lens thickness = " & tlens 94u~:'t>V D<Z]kR( '************************************************************************* W$Z8AZ{E 'Lens index of refraction ryt`yO '************************************************************************* Md>9Daa~ eID = FindMaterial( "Lens" ) LTnbBh*mc GetModelMaterial eID, mat +Al*MusS @6{F4 mat.Nd = nlens UkM#uKr: SetModelMaterial eID, mat kC/An@J^# Print "Set lens index of refraction = " & nlens ffem7eQ !w:pb7+G '************************************************************************* )S|&3\ 'Pupil diameter SnGXEQ '************************************************************************* 2mfG:^^c eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) GT-ONwVDq v=x)]<E"_ 'Adjust pupil diameter (trimming volume inner hole) w9CX5Fg jluv}*If SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" rnM C[
(xMq(g ' Adjust pupil location to just in front of the lens i6xzHfaYG parID = FindFullName( "Geometry.Arizona Eye" ) ?fNUmk^A< eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ,?VYrL count = 0 !>6`+$=U While GetOperationCount(eID)>count !s[gv1 GetOperation eID, count, op
O]Q8&( If op.Type="ShiftZ" Then >\!k~Zi DeleteOperation eID,count *xDV8iu_ count=count-1 cC TTjx{ End If y+$a}=cb0 count=count+1 LN=#&7=$c Wend OwLJS5r@<- op.Type = "ShiftZ" <(BIWm* op.val1 = taq-0.01 zz-X5PFn op.parent = parID qex::Qf AddOperation eID, op r
['zp=9 ;tfGhHpQn Print "Set pupil diameter = " & pupilDiam hGo/Ve+@ `i6q\-12n 'Update AZ Eye subassembly Description #QiNSS eID = FindFullName( "Geometry.Arizona Eye" ) &IkHP/ GetEntity eID, entity r9~I R entity.Description = "Accommodation = " & A & "D" -
*xn`DH SetEntity eID, entity 8FQNeQr oX?~ Update gTg[!}_;\N Print "DONE!" 5
$.az K9S(Xip End Sub /5Xt<7vm8 e(jD[q 如果屈光度是4,光瞳直径是4,则会输出如下数据: |O[ I=! |kqRhR(Ei Accommodation = 4 Diopters 7lG,.W| Pupil Diameter = 4 mm U
sV?} Set aqueous humor thickness = 2.81 &}FWpo! Set anterior lens radius = 10.4 and conic constant = -2.375869 [`bA,)y" Set posterior lens radius = -4.424557 and conic constant = -3.081019 [V41 Gk Set lens thickness = 3.927 *.+N?%sAP) Set lens index of refraction = 1.42672 - 4B& |