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简介 )9B:Y;>) 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。 +Juh:1H <6/= y1QC) 模型 H'Nq#K `Ug tvo 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。 o,1Dqg4P3 Kk=LXmL2 Table 1. AZ眼睛模型的定义 ;g+]klR! 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. n}JPYu NO2(vE 光源 zW5C1:.3K gqfDacDJL 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。 vQgq]mA? t+O e)Ns QD$Gw-U-l= 图1. 光源和提示信息使用 i $C-)d] 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。 $Asr`Q1i
VO_dA4C}z 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 :b@igZ< CW p#^1F 图2. 字母F光源的设定方法光 L5f$TLw
h; FY4 T(4# 图3. 字母F在视网膜上位置点列图 k"0;D-lTZ> 视网膜的散射 6e.[,-eU Z7z]2v3}c 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。 yQ%"U^.m G?xJv`"9iC OhFW*v 图4. 视网膜朗伯散射设定 ($8t%jVWJJ 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。 Da_()e[9p KmmQ ,e% i%F<AY\O) 图5. 视网膜重点采样规格设定 4-^[%&>} 脚本 "VTF}#Uo 2+Yb
7 uI, 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: E
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3{ "O,h 图6. 用户对话框的创建与编辑 Ee)xnY%( 图7. 用户对话框编辑器 +qy6d7^ 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。 n_23EcSy 余下的脚本计算与屈光度有关的所有参数。 >;9NtoE rt}^4IqL 分析 0BK5qz wk @,wOt 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 i=#F)AD^5# B(,:h aAr 图7. 字母F在视网膜上颜色分析
+TSSi em 脚本代码 Fe!9y2Mg Zh'&-c_J Option Explicit 'Remove this to enable non-dimensioned variables to be used. uMd. j$$ zk}{ dG^M: Dim entity As T_ENTITY O|'1B>X Dim op As T_OPERATION >cgpaj x* Dim mat As T_MODELMATERIAL 6R4<J%$P Dim A As Double !Zjq9{t\" Dim pupilDiam As Double k\aK?(.RC7 Dim eID As Long +@:L|uFU Dim parID As Long uM S*(L_ Dim count As Integer #ekM"p Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 6N" l{! Dim tlens As Double, nlens As Double eR;!(Oy=A Dim curv As Double, conic As Double '*T]fND4 Dim ok As Long @dEiVF`4: 4 b,N8 Sub Main 4XJiIa? lr3mE '用户输入对话框 T?wzwGp-[ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ar^i|`D TextBox 220,21,40,21,.TextBox1 'default: 0 Vw~\H Gs/~ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 {y-^~Q"z OKButton 40,91,90,21 g0&\l}&%U CancelButton 190,91,90,21 ]Kh2;>=
Xj Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ,hRN\Kt)p TextBox 220,49,40,21,.TextBox2 'default: 4 [TTSA2 End Dialog <<zI\+V Dim dlg As UserDialog ;rHO&(h- (K<9hL+X ok = Dialog (dlg) 'i|rjW( E6A/SVp If ok=0 Then 'cancel button was pressed ]A+o>#n}x Print "Execution cancelled." ELD!{bMT End |i7a@'0) End If eJ@~o{,?> U[\Vj_?(I 'Assign accommodation and pupil diameter & use defaults if field left empty h~}.G{" If dlg.TextBox1 = "" Then #&8rcu;/ A = 0 'Default accommodation {/8Q)2*>0 Else z`3( ,V A = CDbl(dlg.TextBox1) I;MD>%[W, End If egR-w[{ s0"e' If dlg.TextBox2 = "" Then )"<8K}%! pupilDiam = 4 'Default pupil diameter B80aw>M Else 0C$vS`s& pupilDiam = CDbl(dlg.TextBox2) ~)]} 91p End If ~r*P]*51x EbQa? Print " " -:Rp'SJ Print "Accommodation = " & A & " Diopters" #JW+~FU` Print "Pupil Diameter = " & pupilDiam & " mm" +j/~Af p5f S4o$t-9l ' Calculate new parameters with accommodation 1KE:[YQ1 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness qUJ
aeQ [iS$JG-
Rant = 12.0 - 0.4*A 'Radius of anterior lens gAbD7SE CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens |oFAGP1
zj{s}* Rpost = -5.224557 + 0.2*A 'Radius of posterior lens $jzFc!rs CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens R9o- `Wz 7/IlL tlens = 3.767 + 0.04*A 'Lens thickness
``K#}3 W;_E 4 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction YwDt.6(+, #ToK$8 'Adjust parameters to account for accommodation k;^
: Y3U9:VB '************************************************************************* n# 7Pr/*0 'Aqueous thickness (Position of Lens) &, a3@i '************************************************************************* N"7]R[* eID = FindFullName( "Geometry.Arizona Eye.Lens" ) >{zk
qvsQ& GetCustomElement eID, entity bn9;7`>. QG
gF|c7 parID = FindFullName( "Geometry.Arizona Eye" ) /bRg?Q 5"KlRuv% ' Delete any shift(s) in z PL=^}{r count = 0 6<'K~1do: While GetOperationCount(eID)>count ]ZoPQUS? GetOperation eID, count, op =r.
>N\ If op.Type="ShiftZ" Then OjE`1h\ DeleteOperation eID,count _=XX~^I, count=count-1 QO;4}rq End If `)$_YZq|SR count=count+1 G;iEo4\? Wend _.)eL3OF Jf;?XP]z 'Set new shift in ))h6~1` op.Type = "ShiftZ"
ZI>km?w op.val1 = taq N@T.T=r op.parent = parID k ]a*&me AddOperation eID, op kAYb!h[` Print "Set aqueous humor thickness = " & taq-0.55 )X+mV DvXHK '************************************************************************* SI:ifR&T 'Radius and conic constant of anterior lens e&<yX '************************************************************************* .p`
pG3 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) vw>j J GetConic eID, entity, curv, conic W&Y"K)` uzr\oj+> SetConic eID, entity, 1/Rant, CCant V&{MQWy Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant E>jh"|f:{ ,L>
ar)B '************************************************************************* PXKJ^fa 'Radius and conic constant of posterior lens YPDf
Y<?v '************************************************************************* Av J4\ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) r),PtI0X GetConic eID, entity, curv, conic }ut]\]b l:B;zi`)oB SetConic eID, entity, 1/Rpost, CCpost iPG0o
% Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost YNdrWBf) :a[Ihqfg '************************************************************************* $rB3m~c| 'Lens thickness (Position of posterior lens surface) 9=l.T/?sf '************************************************************************* A;XOT6jv? 5N$E()m$ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 1%[_`J;>Z | s+0~$O; ' Delete any z-shift(s) I,@r5tKo count = 0 4<,|*hAT While GetOperationCount(eID)>count E$s/]wnr[ GetOperation eID, count, op KxGX\
If op.Type="ShiftZ" Then vT^Sk;E DeleteOperation eID,count Z3KO90O!8 count=count-1 ,U,By~s End If (46 {r}_O count=count+1 b,H[I!. % Wend K+\nC)oG x+5k
<Xi} 'Set new z-shift +\
_{x/u1 op.Type = "ShiftZ" !v|ISyK op.val1 = tlens 5v.DX`" op.parent = parID bp<^R AddOperation eID, op |`k
.y]9 Print "Set lens thickness = " & tlens 66&EBX} ]:]H:U]p '************************************************************************* gApoX0nrv 'Lens index of refraction +ZsX*/TOn '************************************************************************* Y
qdWctUY eID = FindMaterial( "Lens" ) F4#g?R::U GetModelMaterial eID, mat 6SM:x]`##, B/f0P(7 mat.Nd = nlens R@Y=o].2 SetModelMaterial eID, mat _cH@I?B Print "Set lens index of refraction = " & nlens [onqNp P@}P k '************************************************************************* D0G-5}s` 'Pupil diameter AnsjmR:Jv '************************************************************************* Fqq6^um eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) \0;(VLN'U R,2=&+ e 'Adjust pupil diameter (trimming volume inner hole) &[R8Q|1j 2RtHg_d_l SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" hn)a@ rZ1Hf11C ' Adjust pupil location to just in front of the lens K/_9f'^ parID = FindFullName( "Geometry.Arizona Eye" ) 'm=*u
SJK eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ~,6b_W p/ count = 0 u0)7i.!M While GetOperationCount(eID)>count fIC9WbiH- GetOperation eID, count, op -4#2/GXNO If op.Type="ShiftZ" Then EOKzzX7 S DeleteOperation eID,count 5`[n8mU count=count-1 5~
' Ie<Y_ End If /?-7Fg+, count=count+1 we7c`1E Wend 0[A9b,MMVO op.Type = "ShiftZ" 9W`Frx'h1 op.val1 = taq-0.01 O09ke-lC op.parent = parID Yd
cK&{ AddOperation eID, op aT l c Oc?+M 5 Print "Set pupil diameter = " & pupilDiam L#[]I, .ae O}^ 'Update AZ Eye subassembly Description (n{wg(R eID = FindFullName( "Geometry.Arizona Eye" ) [`=LTBt GetEntity eID, entity `\|ssC8u entity.Description = "Accommodation = " & A & "D" )u ?' ; SetEntity eID, entity &:B<Q$g# 1n*W2:,z Update {NM+Oj,~' Print "DONE!" f3*?MXxb16 ?/*~;fM End Sub =4!nFi d^ ZMS~\* 如果屈光度是4,光瞳直径是4,则会输出如下数据: E
.6HpIx +A_J1iJ< Accommodation = 4 Diopters ,hxkk` Pupil Diameter = 4 mm HG>j5 Set aqueous humor thickness = 2.81 u~zs*
qp Set anterior lens radius = 10.4 and conic constant = -2.375869 !|?e7u7 Set posterior lens radius = -4.424557 and conic constant = -3.081019 L];y}]:F* Set lens thickness = 3.927 W{cY6@ Set lens index of refraction = 1.42672 *v%rMU7, Set pupil diameter = 4 M.}7pJ7f DONE! 0"k|H& ?ne_m:J[ (文章来源:讯技光电)
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