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简介 Vi'zSR28Z 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。 nUf0TkA 7,"y!\ 模型 A#8J6xcSrL LW!>_~g- 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。 NY"+Qw@$ *1g3,NMA Table 1. AZ眼睛模型的定义 +D
d! 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. rBZ0Fx$/[ L*(`ccU 光源 e>g>)!F H_FT%`iM 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。 PpezWo)9 {iYrC m[_ <7_s'UAL! 图1. 光源和提示信息使用 <ZjT4>< 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。 =hi{J
M ,ut7`_Fy 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。 ;.Y-e
Q, /Csk"IfuO 图2. 字母F光源的设定方法光 i $lp8Y2ih qFN`pe, 图3. 字母F在视网膜上位置点列图 ?.^n,[2 视网膜的散射 ([dJ'OPx$ BKKW3PT 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。 =d#(n M* aY0{v X r7-H`%. 图4. 视网膜朗伯散射设定 wWQt 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。 A$70!5* QB;jZpF ~-
eB 图5. 视网膜重点采样规格设定 .S*VYt%K7 脚本 3 L:SJskYR `Gh J)WA< 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: [xo-ZDIoG WOi+y 图6. 用户对话框的创建与编辑 DdqE6qE 图7. 用户对话框编辑器 :QIf0*.O 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。
Og7^7)) 余下的脚本计算与屈光度有关的所有参数。
_6-N+FI l'7'G$v 分析 kK=f@l yM('!iG*/ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ?-JW2 E"uT Qt>Bvu Q 图7. 字母F在视网膜上颜色分析 v^aI+p6 脚本代码 XbIxGL /sr.MT Option Explicit 'Remove this to enable non-dimensioned variables to be used. z}F^HQ1 T%4yPmY Dim entity As T_ENTITY 5E^P2Mlc Dim op As T_OPERATION O Ke
9/._ Dim mat As T_MODELMATERIAL X@za4d Dim A As Double \%_sL#? Dim pupilDiam As Double (t5vBUj Dim eID As Long }Z)YK}_1 Dim parID As Long e[6Me[b Dim count As Integer ^O<@I Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double d2fiPI7lg Dim tlens As Double, nlens As Double .|0$?w Dim curv As Double, conic As Double duc\/S' Dim ok As Long T?CQgVR o1thGttVDg Sub Main `+i/rc1. wLxuSs| '用户输入对话框 g){gF( Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 #'.
' |z TextBox 220,21,40,21,.TextBox1 'default: 0 2 SU Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 [8>#b_> OKButton 40,91,90,21 :XOjS[wBm CancelButton 190,91,90,21
J^!wk9q Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 vAjog])9s TextBox 220,49,40,21,.TextBox2 'default: 4 pm2] End Dialog 2 ,krVb?< Dim dlg As UserDialog >sQf{uL qe/5'dw ok = Dialog (dlg) N'0nt]&a vhzz(UPUt If ok=0 Then 'cancel button was pressed $."Fz
x Print "Execution cancelled." E:;MI{;7 End AoY!f'Z End If }!"Cvu Oj8D+sC{ 'Assign accommodation and pupil diameter & use defaults if field left empty (:R5"|]@<x If dlg.TextBox1 = "" Then 8!
/ue.T A = 0 'Default accommodation #mD_<@@ Else lT~WP)
A = CDbl(dlg.TextBox1) n g9_c End If _-2;!L#/ H9Vn(A8&` If dlg.TextBox2 = "" Then Mm!;+bM% pupilDiam = 4 'Default pupil diameter h@J3+u< Else n8JM
0 U- pupilDiam = CDbl(dlg.TextBox2) 9*XT|B End If C3~O6<,Jh FGeKhA 8jT Print " " {REGoe=W% Print "Accommodation = " & A & " Diopters" _|{Z850AS Print "Pupil Diameter = " & pupilDiam & " mm" [fY7| )~`UDaj_ ' Calculate new parameters with accommodation 3GrIHiCr taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness At!@Rc qpzyl~g:C Rant = 12.0 - 0.4*A 'Radius of anterior lens (M{>9rk8 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens &Lbwx&!0b L uW""P/ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens _C19eW' CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens a'd=szt uo(LZUjPbN tlens = 3.767 + 0.04*A 'Lens thickness nWhf jvpv1>KYV nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction "p+JME( c2L\m*^o 'Adjust parameters to account for accommodation dp4vybJ ?}= $zN '************************************************************************* riRG9c | 'Aqueous thickness (Position of Lens) TX7dwmt)N '************************************************************************* "<f?.l\+ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 0g; o6Fg GetCustomElement eID, entity 5Zmc3&vRl t_Rj1U parID = FindFullName( "Geometry.Arizona Eye" ) h"'}Z^ ?mN!9/DIc ' Delete any shift(s) in z 8k+k\V{ count = 0 L\!Oj5 While GetOperationCount(eID)>count 4,?beA GetOperation eID, count, op lkC| g%f If op.Type="ShiftZ" Then f1?%p)C DeleteOperation eID,count Ocn@JOg count=count-1 P+C5
s End If EQX<<x" count=count+1 [;o>q;75Jz Wend BuUM~k&SY `cIeqp 'Set new shift in CrG!8} op.Type = "ShiftZ" &}K%F)S op.val1 = taq P>$+XrTE op.parent = parID InRcIQT AddOperation eID, op u9u'5xAO Print "Set aqueous humor thickness = " & taq-0.55 [nlq(DGJhp t<RPDQ> '*************************************************************************
kKY,&Fn- 'Radius and conic constant of anterior lens xMa9o '************************************************************************* .F[5{XV eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) qT&zg@m GetConic eID, entity, curv, conic `tcX[(` DZA '0- SetConic eID, entity, 1/Rant, CCant d`%7Pk Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ;%cW[*Dw J3B+WD] '************************************************************************* T)Q_dF.N 'Radius and conic constant of posterior lens !89hO4 0r '************************************************************************* 51*[Ibx eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) N P5K1: GetConic eID, entity, curv, conic JXR]G UPPlm\wb* SetConic eID, entity, 1/Rpost, CCpost /b/ 6*& Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost NRspi_&4J !f}D*8\f '************************************************************************* 2 zG;91^ 'Lens thickness (Position of posterior lens surface) _c-(T&u< '************************************************************************* ps:E(\ ZS`Kj(D parID = FindFullName( "Geometry.Arizona Eye.Lens" ) I :bT"N V
'fri/Z ' Delete any z-shift(s) =Lnip<t>ja count = 0 "v0SvV<7 While GetOperationCount(eID)>count
KP$AT}D GetOperation eID, count, op U!E}(9
tb If op.Type="ShiftZ" Then _::ssnG3jT DeleteOperation eID,count {M=*>P]E count=count-1 ic l]H End If a=v H:D count=count+1 i CB:p Wend vj]h[=: }([}A`@ 'Set new z-shift &5[+p{2 op.Type = "ShiftZ" )h{+pK op.val1 = tlens s?4nR:ZC} op.parent = parID 73SH[f[g AddOperation eID, op @xBO[v Print "Set lens thickness = " & tlens :h!'\9 H]f[r~ '************************************************************************* 2]FRIy
d 'Lens index of refraction z\?<j%e!t '************************************************************************* #B#xSmak eID = FindMaterial( "Lens" ) sD&V_
&i GetModelMaterial eID, mat LB9W.cA
C}DIm&)) mat.Nd = nlens xr7M#n SetModelMaterial eID, mat zJ:%iL@ Print "Set lens index of refraction = " & nlens z2!4w +2 A>HCX 4i '************************************************************************* wM3m'# xJ 'Pupil diameter 5g$>J)Ry '************************************************************************* IS;[oJef eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Z%=A[`5] ]KG.-o30 'Adjust pupil diameter (trimming volume inner hole) 8U4In[4 2iO{*cB SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Vo%Z| 4^d).{&X ' Adjust pupil location to just in front of the lens )r)ZmS5O parID = FindFullName( "Geometry.Arizona Eye" ) !,]c}Y{i eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) [,MK)7DU count = 0 `U>2H4P While GetOperationCount(eID)>count BQ70<m2D$ GetOperation eID, count, op ELG9ts+5Uj If op.Type="ShiftZ" Then y0/FyQs DeleteOperation eID,count H0.A;` count=count-1 /N obS'd End If #EB
Rc4>, count=count+1 iun_z$I<+Z Wend BNFYUcVP op.Type = "ShiftZ" `R -?+76? op.val1 = taq-0.01 .~q>e*8AH op.parent = parID ZvO1=*
J, AddOperation eID, op WN#2<XjG ra_v+HR7 Print "Set pupil diameter = " & pupilDiam In+2~Jw/2! '*
/$66| 'Update AZ Eye subassembly Description acQHqR eID = FindFullName( "Geometry.Arizona Eye" ) 2~B5?(g GetEntity eID, entity QXl~a%lB entity.Description = "Accommodation = " & A & "D" EQ|Wke SetEntity eID, entity ?1] \3nj jpoNTl' Update BglbQ'6p Print "DONE!" 82?LZ?!PD UdA,.C0 End Sub |L:X$oM p<wC{D 如果屈光度是4,光瞳直径是4,则会输出如下数据: !C^>tmqS (NJ.\m Accommodation = 4 Diopters }m7$,'C%P Pupil Diameter = 4 mm B7.&yXWgn Set aqueous humor thickness = 2.81 <E^;RG Set anterior lens radius = 10.4 and conic constant = -2.375869 _9Rj, Set posterior lens radius = -4.424557 and conic constant = -3.081019 #uICHt3 Set lens thickness = 3.927 LX=v
_}l
J Set lens index of refraction = 1.42672 d 3#e7rQ8 Set pupil diameter = 4 a$bE2'cb DONE! ziM@@$.F )V*`(dn'zm (文章来源:讯技光电)
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