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简介 er&uC4Y]a 6-)7:9y 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。 |Ba4 G` Fr1;)WV 模型 Z'7 c^c7_ |!?2OTY 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。 XLkL#&Ir T*7S;<2
Table 1. AZ眼睛模型的定义 @9n
#vs 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. i{Y=!r5r (OM?aW 光源 Q
`J,dzY <Tj"GVZAEO 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。 T%M1[<"Q dSA
[3V M="WUe_ 图1. 光源和提示信息使用 X
,V= od> 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。 -o=P85V hP'~ 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。 8:3oH!n TFiuz;*| 图2. 字母F光源的设定方法光 w>H%[\Qs >S?C {_g 图3. 字母F在视网膜上位置点列图 &0;{lS[N:L 视网膜的散射 [[Jv)?jm (%ri#r 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。 ECmHy@( i_oro"%yL qaCi)f!Dl 图4. 视网膜朗伯散射设定 DK#65H' 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。 ZNL;8sI?> a<a&63 O+{pF.P#V 图5. 视网膜重点采样规格设定 ($[r>)TG 脚本 }`+^|1 &vJ(P!2f< 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: [9YlLL@ Q
KcF1? 图6. 用户对话框的创建与编辑 D@sx`H( 图7. 用户对话框编辑器 34++Rr [G 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 cpr{b8Xb8& 余下的脚本计算与屈光度有关的所有参数。 n]6}yJJo qH{8n` 分析 aPY>fy^8D c'TiWZP~ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 %%-U. &<fRej]v 图7. 字母F在视网膜上颜色分析 {"gyXDE1 脚本代码 x3Dg%=R &}L36|A: Option Explicit 'Remove this to enable non-dimensioned variables to be used. pjmGzK rH2tC=% Dim entity As T_ENTITY r0hta)xa Dim op As T_OPERATION }jyS\drJ Dim mat As T_MODELMATERIAL Im' :sJ31 Dim A As Double f!uA$uLc Dim pupilDiam As Double E{+c*sz Dim eID As Long %1 VNP(E Dim parID As Long O0=,&=i Dim count As Integer **w*hd] Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double cc2 oFn Dim tlens As Double, nlens As Double ?-.Ep0/ Dim curv As Double, conic As Double cciAMQhA Dim ok As Long +qSr=Y:+ o?Tp=Ge Sub Main qqz,~EhC nM (=bEX '用户输入对话框 @dT: 1s Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 yTq(x4] TextBox 220,21,40,21,.TextBox1 'default: 0 }G,SqpcG Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 {Y@-*pL] OKButton 40,91,90,21 :)+@qxTy CancelButton 190,91,90,21 :UJUh/U Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 nX.s h TextBox 220,49,40,21,.TextBox2 'default: 4 4MF}FS2) End Dialog oX:1 qJrC Dim dlg As UserDialog Z,8+@ $jm>tW&; ok = Dialog (dlg) tE9_dR^K 4-}A'fTU8 If ok=0 Then 'cancel button was pressed ad3z]dUZ9 Print "Execution cancelled." .'NO~ End C$..w80/1 End If bh;b`
5 !ovZ>,1 'Assign accommodation and pupil diameter & use defaults if field left empty qY~$wVY( If dlg.TextBox1 = "" Then SFk11 A = 0 'Default accommodation .5[LQR Else ,TfI A = CDbl(dlg.TextBox1) Y4~wNs6 End If yY@s(: ,d [b"]Zy If dlg.TextBox2 = "" Then +O!M> pupilDiam = 4 'Default pupil diameter G}?P
r4Gj Else }2!5#/^~ pupilDiam = CDbl(dlg.TextBox2) vA7jZw End If p`l[cVQ< 6t mNfI34 Print " " '__3[D Print "Accommodation = " & A & " Diopters" tx1m36a" Print "Pupil Diameter = " & pupilDiam & " mm" "JUQ)> !? eS@!\Hx ' Calculate new parameters with accommodation zs]/Y2 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness :Z]+Z_9p cmGj0YUQ1 Rant = 12.0 - 0.4*A 'Radius of anterior lens MCrO]N($b CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens }$k`[ivBx( bmq XP Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ";Ig%] CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Qpv}N*v^ s3E~X tlens = 3.767 + 0.04*A 'Lens thickness ^B6i6]Pd=9 >~wk nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction R#Nd|f< A*;^F]~' 'Adjust parameters to account for accommodation :mtw}H 'F8 % x*Ec[l
'************************************************************************* Gv+Tg/ 'Aqueous thickness (Position of Lens) vyx\N{ '************************************************************************* 53+rpU_ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) DGfQo5# GetCustomElement eID, entity qpwh #^2 acju!,G parID = FindFullName( "Geometry.Arizona Eye" ) IweK!,:>dN Q3O .<9S ' Delete any shift(s) in z SnF[mN' count = 0 674oL, While GetOperationCount(eID)>count ch8w' GetOperation eID, count, op jUR# If op.Type="ShiftZ" Then Qx,$)|_ DeleteOperation eID,count 3;l>x/amk count=count-1 gWv+i/, End If \/4%[Q2QDm count=count+1 ,JBw$C Wend oY6|h3T=Q$ }:D~yEP 'Set new shift in |%cO"d^ri op.Type = "ShiftZ" MbF e1U]B op.val1 = taq ]%Yis=v op.parent = parID i7FR78^ AddOperation eID, op ].f,3itg& Print "Set aqueous humor thickness = " & taq-0.55 t-x"( +2fJ '************************************************************************* `"b7y(M 'Radius and conic constant of anterior lens Z
*<x '************************************************************************* m^x\@!N:( eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) jhbH6=f4]^ GetConic eID, entity, curv, conic >h( rd1
:E&T}RN SetConic eID, entity, 1/Rant, CCant yz$1qEII`q Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #!&R7/
KdD |QTqa~~B '************************************************************************* 'U{:
zBh 'Radius and conic constant of posterior lens SF7b1jr '************************************************************************* 32|L
$o eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) @
h`Zn1; GetConic eID, entity, curv, conic qe"6#@b *| jMWwu+w SetConic eID, entity, 1/Rpost, CCpost vMdhNOU Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ^W[`##,{Od [,$mpJCI '************************************************************************* 7Z~szD 'Lens thickness (Position of posterior lens surface) kDP^[V
P+ '************************************************************************* la{uJ9Iw@} -x\l<\* parID = FindFullName( "Geometry.Arizona Eye.Lens" ) _7"W\gn:9 PyxN _agf ' Delete any z-shift(s) d#:J\2V"R count = 0 p}|wO&4h While GetOperationCount(eID)>count 4x?u5L
9o GetOperation eID, count, op UkbQ'P+oS If op.Type="ShiftZ" Then H1qw1[%0y DeleteOperation eID,count C{,] 1X6g count=count-1 JU \J
End If ZV4'
|q count=count+1 (ai-n,y Wend vk+%#w '"\Mjz)/ 'Set new z-shift /~huTKA} op.Type = "ShiftZ" il%tu<E#J~ op.val1 = tlens '<D}5u72 op.parent = parID cE>/iZc AddOperation eID, op gL"Q.ybA Print "Set lens thickness = " & tlens
9QZ wUQ ayz1i:Q| '************************************************************************* WzbN=&
C]h 'Lens index of refraction M]TVaN$v# '************************************************************************* PlRs-% d eID = FindMaterial( "Lens" ) [\n.[4gq" GetModelMaterial eID, mat |F{E4mg(o cD@lorj mat.Nd = nlens uN0fWj] SetModelMaterial eID, mat }4]x"DfIg Print "Set lens index of refraction = " & nlens [y;ZbfMP|o PH!B /D5G '************************************************************************* x)Kh_G 'Pupil diameter T\CQ '************************************************************************* Awf=yE: eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) @_ZWP c;}n=7,>:L 'Adjust pupil diameter (trimming volume inner hole) >Mw =}g@P b=\3N3OX SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" :Zo2@8@7 QnLgP7Ft ' Adjust pupil location to just in front of the lens rWKLxK4oU parID = FindFullName( "Geometry.Arizona Eye" ) l<_mag/j9o eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) _?LI0iIFx count = 0 u`,R0=<4 While GetOperationCount(eID)>count "dOY_@kg GetOperation eID, count, op zb,`K*Z{ If op.Type="ShiftZ" Then !O_^Rn+<2 DeleteOperation eID,count ~M1%,] count=count-1 Yx c >+mx End If Xb
1 ^Oj count=count+1 m?G+#k;K Wend t1s@Ub5);I op.Type = "ShiftZ" 2DdLqZY# op.val1 = taq-0.01 9gayu<J op.parent = parID tzJtd AddOperation eID, op 5j5t?G;d, v~QZO4[' Print "Set pupil diameter = " & pupilDiam qZ1PC> Q_Squuk 'Update AZ Eye subassembly Description :u93yH6~8 eID = FindFullName( "Geometry.Arizona Eye" ) c4W"CD;D GetEntity eID, entity PP|xIAc entity.Description = "Accommodation = " & A & "D" j'cCX[i SetEntity eID, entity :8T@96]P '-TFr NO;h Update S]@iS[|? Print "DONE!" {'aqOlw3<j g&5VorGx End Sub 8#-}3~l[ S@-X?Lu 如果屈光度是4,光瞳直径是4,则会输出如下数据: oC>~r1.j Q-CVq_\3I Accommodation = 4 Diopters m':m`,c! Pupil Diameter = 4 mm <-7Ha_# Set aqueous humor thickness = 2.81 .AS,]*?Zn% Set anterior lens radius = 10.4 and conic constant = -2.375869 )A;<'{t #L Set posterior lens radius = -4.424557 and conic constant = -3.081019 =J\7(0Dz4t Set lens thickness = 3.927 -W vAmi Set lens index of refraction = 1.42672 U?yXTMD Set pupil diameter = 4 zaPR>:r0 DONE! P~>nlm82]
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