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简介 {z7kW@c 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。 E9:p A5H-j Z~HLa 模型 T*zy^we J|N>}di 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。 ~0Xx] 2hE+Om^n Table 1. AZ眼睛模型的定义 W Z^u%Z 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.
`d!~)D k~pbXA*u 光源 <77v8=as5 'kk
B>g7B 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。 lBfG#\rdW~ tk'3Q 1L q{RT~,% 图1. 光源和提示信息使用 xI^nA2g 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。 -mqTlXM Nj;G%KAP
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。 JU RJN+)z 99&PY[f:{ 图2. 字母F光源的设定方法光 #{|F2AM I>45xVA 图3. 字母F在视网膜上位置点列图 i0*6o3h 视网膜的散射 aXyg`CDv :qO)^~x 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。 I=o/1:[- i T&Y9 =-8y= 图4. 视网膜朗伯散射设定 iM{UB=C 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。 !-Md+I_ >d#Ks0\& $Qq5Fx9kU 图5. 视网膜重点采样规格设定 G~`nLC^Y 脚本 @-5V~itW b2HHoIT 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: 6yPh0n i`HXBq!|w 图6. 用户对话框的创建与编辑 S`Wau/7t 图7. 用户对话框编辑器 ~h6aTN 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 -
]Mp<Y 余下的脚本计算与屈光度有关的所有参数。
"xY]& D-4\AzIb 分析 .T }q"
<%Afa# 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ~4[4"Pi>| DJ<F8-sb2r 图7. 字母F在视网膜上颜色分析 EJZb3 脚本代码 L(i0d[F &P3ep[]j Option Explicit 'Remove this to enable non-dimensioned variables to be used. !L\P.FP7b ik Pm,ZN Dim entity As T_ENTITY QX&1BKqWn Dim op As T_OPERATION =K\.YKT Dim mat As T_MODELMATERIAL 0I
\l_St@ Dim A As Double /J` ZO$ Dim pupilDiam As Double k4Ub+F Dim eID As Long kmfxk/F} Dim parID As Long >;zQ.2* Dim count As Integer #ZvDf5A Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double /|z_z%= Dim tlens As Double, nlens As Double +
c"$-Jr Dim curv As Double, conic As Double W!
q-WU Dim ok As Long cpg+-Zf% >zY~")|R( Sub Main CPS1b &[iunJv:eq '用户输入对话框 NamO5(1C Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 UO{3vry48 TextBox 220,21,40,21,.TextBox1 'default: 0 WjsE#9D!of Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ;H:+w\?8f$ OKButton 40,91,90,21 ~G*eJc0S: CancelButton 190,91,90,21 q'~F6$kv5 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 { WW!P,w TextBox 220,49,40,21,.TextBox2 'default: 4 p^ojhrr End Dialog }|!9aojr Dim dlg As UserDialog &H<n76G S&`iEwG ok = Dialog (dlg) |g}~7*+i js<}>wD7< If ok=0 Then 'cancel button was pressed TB Print "Execution cancelled." SF2< End V]I+>Zn| 7 End If {s/u[T_D2 `lA[-x~ 'Assign accommodation and pupil diameter & use defaults if field left empty ); <Le6 If dlg.TextBox1 = "" Then w`;>+_ E7 A = 0 'Default accommodation ~\~K,v Else `tb@x ^ A = CDbl(dlg.TextBox1) ~56F<=#, End If 6V@?/B ]&l%L4Z If dlg.TextBox2 = "" Then :i>/aRNh1 pupilDiam = 4 'Default pupil diameter Kc[Y .CH Else q&`>&k pupilDiam = CDbl(dlg.TextBox2) +f- E8q End If 7w]NG`7 !O-9W=NJ Print " " WOaj_o Print "Accommodation = " & A & " Diopters" oykqCN Print "Pupil Diameter = " & pupilDiam & " mm" wmf#3"n o/Cu^[an ' Calculate new parameters with accommodation v%%;Cp73 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness f<T"# G$5 sF=8E8qa Rant = 12.0 - 0.4*A 'Radius of anterior lens KKLW-V\6K CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens a6v ls]? NtnKS@Ht Rpost = -5.224557 + 0.2*A 'Radius of posterior lens LG
qg0( CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens -P5M(Rt
7Odw{pc tlens = 3.767 + 0.04*A 'Lens thickness R:LThFx R6KS&Ge_ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction {_{&t>s2 (i*;V0 'Adjust parameters to account for accommodation 9 yE
u(`,7 o " '************************************************************************* WO=,NQOw 'Aqueous thickness (Position of Lens) vKvT7Zxc '************************************************************************* (Z72 3) eID = FindFullName( "Geometry.Arizona Eye.Lens" ) @aC2] GetCustomElement eID, entity H!+T2<F9R edW:(19} parID = FindFullName( "Geometry.Arizona Eye" ) a.5^zq7#! h5.>};"@' ' Delete any shift(s) in z
h'_@ count = 0 Nhm)bdv] While GetOperationCount(eID)>count z&@Vg`w" GetOperation eID, count, op Ehv*E If op.Type="ShiftZ" Then #ir~v>J|| DeleteOperation eID,count {hLS,Me count=count-1 Wr%E}mX- End If N){/#3 count=count+1 sP+ZE>7 Wend 3;h%mkKQ+ [7:(e/& 'Set new shift in ~e)`D nJ op.Type = "ShiftZ" ?+WSYg0 op.val1 = taq !VfP#B6. op.parent = parID y_=},a AddOperation eID, op _Zq2 <: Print "Set aqueous humor thickness = " & taq-0.55 nDhD"rc '{t&!M` '************************************************************************* {'QA0K 'Radius and conic constant of anterior lens U6pG '************************************************************************* QE.a2
} eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) abVz/R/o GetConic eID, entity, curv, conic -zq_W+)ks jd&kak SetConic eID, entity, 1/Rant, CCant c-2##Pf_8O Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant .-6B6IEI_" .\?)O+J! '************************************************************************* <~[A 'Radius and conic constant of posterior lens iYyJq;S
'************************************************************************* &mM[q'V eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) U# jbii6e GetConic eID, entity, curv, conic 3r)<:4a
u& $
+` SetConic eID, entity, 1/Rpost, CCpost fgg;WXcT ~ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost tyH*epanw 5Z`9L|3d '************************************************************************* *W#_W]Tu 'Lens thickness (Position of posterior lens surface) #^>5,M2 '************************************************************************* zdwr5k } h.]sF parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5jpb`Axj# DKjkO5R\ ' Delete any z-shift(s) l~/g^lN count = 0 -qPYm?$ While GetOperationCount(eID)>count {!B^nCSL GetOperation eID, count, op ?W %9H\; If op.Type="ShiftZ" Then vq df-i DeleteOperation eID,count (>OCLmV$ count=count-1 483BrFV End If SLa\F count=count+1 )_bR"!Z Wend >l\?K8jL9 xJvM
l`2; 'Set new z-shift !;YmLJk;hN op.Type = "ShiftZ" eQ}o;vJN op.val1 = tlens A&$oiLc op.parent = parID f2sv$#' AddOperation eID, op `XwFH#_ Print "Set lens thickness = " & tlens H$
!78/f l%aiG+z%6} '************************************************************************* `dH[&=S 'Lens index of refraction a!1\,. '************************************************************************* 24TQl<H{ eID = FindMaterial( "Lens" ) (W<n<sl:- GetModelMaterial eID, mat IT3xX=|b PD$gW`V mat.Nd = nlens !,mv 7Yj SetModelMaterial eID, mat `YDe<@6' Print "Set lens index of refraction = " & nlens n$* 'J9W~ 7R 40t3 '************************************************************************* pZu2[ 'Pupil diameter Ip/_uDi+!Z '************************************************************************* cG|ihG5) eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 9B lc .c[v /SB] 'Adjust pupil diameter (trimming volume inner hole) ZiBTe,; aj1o SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" j5*W[M9W ! 5rja-h ' Adjust pupil location to just in front of the lens :V>M{vd parID = FindFullName( "Geometry.Arizona Eye" ) w6k\po= eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) c=U1/=R5 count = 0 sLE@Cm]k While GetOperationCount(eID)>count f^8,Z+n GetOperation eID, count, op O.n pi: a If op.Type="ShiftZ" Then o}XbFLn DeleteOperation eID,count -kp!.c count=count-1 RCED
K\*m End If S7cxEOfAu count=count+1 Ou~|Q&f' Wend 7-nz'-' op.Type = "ShiftZ" l65-8 op.val1 = taq-0.01 U*G9 fpVy op.parent = parID i^[yGXtW AddOperation eID, op FcnSO0G% fqaysy Print "Set pupil diameter = " & pupilDiam y*,3P0*z %m:T?![XO 'Update AZ Eye subassembly Description "(uEcS2< eID = FindFullName( "Geometry.Arizona Eye" ) b?#k GetEntity eID, entity 'H0b1t1S% entity.Description = "Accommodation = " & A & "D" {/]Ks8`Dm SetEntity eID, entity v3w5+F Y[=Gv6Fr Update p&wXRI Print "DONE!" \29a@ 6 $9v:(:!Bm End Sub m^dKww M6E.!Cs 如果屈光度是4,光瞳直径是4,则会输出如下数据: (>*<<a22 |A_yr/f Accommodation = 4 Diopters `nA_WS Pupil Diameter = 4 mm 38IVSK_ Set aqueous humor thickness = 2.81 M{S7tMX Set anterior lens radius = 10.4 and conic constant = -2.375869 v~>^c1: Set posterior lens radius = -4.424557 and conic constant = -3.081019 [4:_6vd7X Set lens thickness = 3.927 \BC|`)0h Set lens index of refraction = 1.42672 k'uN2m Set pupil diameter = 4 )Yvf9dl DONE! _@3?yv~ D @`<v d@ (文章来源:讯技光电)
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