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简介 489xoP #0:rBKm, 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。 9DmFa5E ]m :Y|,:6 模型 'A,)PZL9i $q##Tys 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。 6@VgLa, e0M'\'J Table 1. AZ眼睛模型的定义 B"rO 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. +}
y"S - r3+ 光源 ]wUH*\(y Khh}flRy 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[ZGY,8 B2Kh~Xd bs'hA@r 图1. 光源和提示信息使用 UZ1Au;(| 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。 WIN3*z7oW A*{CT> 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。 2;x+#D8 Nj.;mr< 图2. 字母F光源的设定方法光 eVzZfB-=4} :_h#A}8Xd 图3. 字母F在视网膜上位置点列图 3a'#Z4Z- 视网膜的散射 ? ph>:M 1/v#Z#3[ 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。 xKkXr-yb`f F#~*j w3&L 6|, 图4. 视网膜朗伯散射设定 7u:QT2=& 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。 9TbbIP1 kz G W/ x->+wJm@s 图5. 视网膜重点采样规格设定 LKA/s ~G 脚本 L9]d$ r" Z^J7r&\V 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: J$d']%Dwb qYQ
vjp 图6. 用户对话框的创建与编辑 ZcN#jnb0/ 图7. 用户对话框编辑器 72vp6/;) 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。 /I:&P Pff 余下的脚本计算与屈光度有关的所有参数。 [{:
l? -@XOe&q 分析 Lf`<4 P e|q~t
{=9S 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 *-S?bv,T' CaVVlL 图7. 字母F在视网膜上颜色分析 6Fc*&7Z+ 脚本代码 A1*\ \[ r^{Bw1+ Option Explicit 'Remove this to enable non-dimensioned variables to be used. h@TP= Yy;BJ_ Dim entity As T_ENTITY #|T2`uYotf Dim op As T_OPERATION P26"z))~d Dim mat As T_MODELMATERIAL Pj_*,L`mZ Dim A As Double '.jYu7
Dim pupilDiam As Double @)wsHW%cjz Dim eID As Long =mSu^q(l Dim parID As Long \uO^wJ} Dim count As Integer vpC?JXz=H Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double LQR^lD+_= Dim tlens As Double, nlens As Double "ji+~%`^[t Dim curv As Double, conic As Double q7I!wD9Cff Dim ok As Long bn7g!2 M@Ti$= Sub Main Xpt9$=d HA[7)T N1E '用户输入对话框 4_# (y^9 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 //RD$e?h~ TextBox 220,21,40,21,.TextBox1 'default: 0 *U$%mZS]1 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 8c>xgFWp9 OKButton 40,91,90,21 Vt,P.CfdC CancelButton 190,91,90,21 Xkk 8#Y": Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ;%k C?Vzi TextBox 220,49,40,21,.TextBox2 'default: 4 D]5j?X' End Dialog YI`BA`BQ8 Dim dlg As UserDialog xo2jfz QKhGEW~G ok = Dialog (dlg) $/ $Hi U`. :^-\KE`3 If ok=0 Then 'cancel button was pressed 2H`>Kj Print "Execution cancelled." y0p\Gu;3j End )[u'LgVN/L End If FlUO3rc| Y/?z8g'p 'Assign accommodation and pupil diameter & use defaults if field left empty dn:\V?9 If dlg.TextBox1 = "" Then jeB"j A = 0 'Default accommodation 7#SfuZ0@ Else
d ^zuo A = CDbl(dlg.TextBox1) abCxB^5VL End If H7k@Br sk*vmxClY If dlg.TextBox2 = "" Then 3sW!ya-VZ pupilDiam = 4 'Default pupil diameter J#q^CWN3R Else |>1#)cONW pupilDiam = CDbl(dlg.TextBox2) ,`YIcrya: End If @sW!g;\T )3<>H!yG} Print " " 5X9L h_p Print "Accommodation = " & A & " Diopters" &aa3BgxyE Print "Pupil Diameter = " & pupilDiam & " mm" i29a1nD4Hm ;]bW ' Calculate new parameters with accommodation 4Xww(5?3 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness TQPrOs? o,S(;6pDJ Rant = 12.0 - 0.4*A 'Radius of anterior lens fJ6Q:7 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens U9*< dR !6z{~Z: Rpost = -5.224557 + 0.2*A 'Radius of posterior lens S]Di1E^r;_ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens hztqZ: NjPQT9&3h tlens = 3.767 + 0.04*A 'Lens thickness {[hgSVN; rO YD[+ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction %|1s9?h7\ JT~Dr KI_ 'Adjust parameters to account for accommodation \ H#" TAqX
f_ '************************************************************************* mx}4iO:Xp 'Aqueous thickness (Position of Lens) L"NfOST3'R '************************************************************************* l;&kX6 w eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ) jt?X} GetCustomElement eID, entity kP5G}Bp cV_-Bcb parID = FindFullName( "Geometry.Arizona Eye" ) C\vOxBAB Qpj[]c5 ' Delete any shift(s) in z mlUj%:Gm# count = 0 rl&.|;5uH; While GetOperationCount(eID)>count atmW? Z GetOperation eID, count, op K4+|K:e If op.Type="ShiftZ" Then P2|+7D: DeleteOperation eID,count -yTIv*y count=count-1 wh2E$b(- End If JG7K-W|!c count=count+1 N R4\TU Wend F2ISg' m(^N8k1K; 'Set new shift in g!o2vTt5 op.Type = "ShiftZ" euW op.val1 = taq ^HtB!Xc op.parent = parID `e?~c'a@ AddOperation eID, op ^4'!B
+}F Print "Set aqueous humor thickness = " & taq-0.55
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}1mRv y$_]}<b '************************************************************************* 8?x:PkK 'Radius and conic constant of anterior lens ?Zk;NL9 '************************************************************************* jA[")RVG eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Zm7,O8 GetConic eID, entity, curv, conic
U0srwt97S B@VAXmCaoV SetConic eID, entity, 1/Rant, CCant %DA`.Z9# Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 0
0|!g"E>$ AT1{D!b '************************************************************************* t7sEY 'Radius and conic constant of posterior lens x5Fo?E '************************************************************************* kHhku!CH eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) rLA-q|| GetConic eID, entity, curv, conic *[BtW56- h@\HPYi#. SetConic eID, entity, 1/Rpost, CCpost G007[| Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost rKd|s7l 53pT{2]zAi '************************************************************************* 0IA'5) 'Lens thickness (Position of posterior lens surface) )0"T?Ivp] '************************************************************************* }UQ,B K[
S>EITr parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 0vBQzM Q X8?@Y@ ' Delete any z-shift(s) v&3"(fp count = 0 JnIG;/ While GetOperationCount(eID)>count :XPat93w GetOperation eID, count, op ,8d&uR}x If op.Type="ShiftZ" Then z"QXPIXPk DeleteOperation eID,count [?;L count=count-1 B., BP End If Ro<x#Uo count=count+1 ?4Fev_5m Wend VB T66kV ;OD-?bC 'Set new z-shift QnS#"hc\a op.Type = "ShiftZ" _@gg,2
u- op.val1 = tlens |$ZS26aYw} op.parent = parID _`0DO4IU AddOperation eID, op jG)66E*" Print "Set lens thickness = " & tlens J$sp6g>K +aPe)U<t '************************************************************************* Q)qJ6-R|HD 'Lens index of refraction M"u=)CT '************************************************************************* ]#rV]As eID = FindMaterial( "Lens" ) !|]k2=+I GetModelMaterial eID, mat qLc&.O.= ua &uR7 mat.Nd = nlens a2i:fz=[ SetModelMaterial eID, mat QZa^Cng~ Print "Set lens index of refraction = " & nlens d(R8^v/L h4MBw=Tz~ '************************************************************************* rg]b$tL~ 'Pupil diameter Tyb'p9 '************************************************************************* aRI. &3- eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ,1lW`Krx (nuTfmt> 'Adjust pupil diameter (trimming volume inner hole) -eS r \u[5O@v# SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" "&^KnWk= (b&Z\?" ' Adjust pupil location to just in front of the lens R\#5;W^ parID = FindFullName( "Geometry.Arizona Eye" ) &TrL!9FtJ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) .pm%qEh count = 0 TL7qOA7^X While GetOperationCount(eID)>count 0Q,Tcj GetOperation eID, count, op a>,_o(]cW If op.Type="ShiftZ" Then /Dt:4{aTOC DeleteOperation eID,count [Fk|m1i! count=count-1 >TawJ"q-6R End If YN:Sn\`D 8 count=count+1 ^gpd '*b Wend 6cbV[!BL op.Type = "ShiftZ" TeR bW op.val1 = taq-0.01 T?.l_"%%d op.parent = parID KZ^>_K& AddOperation eID, op EGFPv'De CtD<%v3` Print "Set pupil diameter = " & pupilDiam {Dy,|}7s ;:J"- p 'Update AZ Eye subassembly Description ,pf\g[tz eID = FindFullName( "Geometry.Arizona Eye" ) QyZ'%T5J GetEntity eID, entity sE|8a entity.Description = "Accommodation = " & A & "D" ;b=7m#5 SetEntity eID, entity HJpx,NU' w-v8P`V Update k*F9&-rtN Print "DONE!" |o(te $M4_"!
End Sub $-!7<a- 6Rq +=X 如果屈光度是4,光瞳直径是4,则会输出如下数据: aYHs35 ^"vmIC.h Accommodation = 4 Diopters :fy,%su Pupil Diameter = 4 mm ^(7l! Set aqueous humor thickness = 2.81 pI>GusXg Set anterior lens radius = 10.4 and conic constant = -2.375869 Tkp"mT
v?< Set posterior lens radius = -4.424557 and conic constant = -3.081019 <pS#wTsN4% Set lens thickness = 3.927 F*Yx1vj Set lens index of refraction = 1.42672 hg'eSU$J Set pupil diameter = 4 0D `9 DONE! \RFA?PuY Dsv2p~ QAZs1;lU QQ:2987619807 HAs/f#zAk6
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