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简介 J@_ctGv =-KMb`xT 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。 H#i{?RM@l E<E3&;qD 模型 J-xS:Ha'l 7%MbhlN. 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。 X(A.X:" xYfD()w<I Table 1. AZ眼睛模型的定义 2f>PO +4S{ 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. fB1TFtAh /PzcvN
光源 >j*;vG5T `'I{U5;e 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。 h6_(?|:-( 5| B(\wqG ritBU:6 图1. 光源和提示信息使用 3S*AxAeg 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。 0'5/K , ;G |i^ 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。 6$U]9D t5B7I59 图2. 字母F光源的设定方法光 JyL a#\ R uo\ .7[1
图3. 字母F在视网膜上位置点列图 ~y HU^5D 视网膜的散射 N_eX/ux Q=mI9 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 Z@a9mFI? VhL{'w7f NLS"eDm 图4. 视网膜朗伯散射设定 (8$k4`T> 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。 3_Cp%~Gi-_ {\H/y c|@ IW=cym7 图5. 视网膜重点采样规格设定 ]\-^>!F #K 脚本 S$TmZk= G!w"{Bk?9 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: Jn:ZYqc M_v?9L 图6. 用户对话框的创建与编辑 3E3U /K 图7. 用户对话框编辑器 Snp|!e 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 z]B]QB
Y[ 余下的脚本计算与屈光度有关的所有参数。 Od+6 -J <8,o50`B 分析 z>sbr<doa 8Jf.ECQT 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 [B@'kwD\l }En 图7. 字母F在视网膜上颜色分析 De7Ts 脚本代码 F+R?a+e pl@O
N"=[ Option Explicit 'Remove this to enable non-dimensioned variables to be used. O[tvR:Nh k@zy Dim entity As T_ENTITY Z;9>S=w! Dim op As T_OPERATION --;@2:lg{ Dim mat As T_MODELMATERIAL rX_@Ihv' Dim A As Double O~j> ? Dim pupilDiam As Double Grs]d-xI Dim eID As Long {{V8;y
Dim parID As Long |*Z$E$k: Dim count As Integer ?
WJ> p Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double SJD@&m%?[ Dim tlens As Double, nlens As Double #/PA A Dim curv As Double, conic As Double f#+el
y Dim ok As Long EY*(Bw *6HTV0jv Sub Main coYij " \I4u{zC '用户输入对话框 KiG p[eb Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ; ^t{Il'j TextBox 220,21,40,21,.TextBox1 'default: 0 zJe#m|Z Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 r0p w_j OKButton 40,91,90,21 d%l{V6 CancelButton 190,91,90,21 %%(R@kh9 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 I*9e]m" TextBox 220,49,40,21,.TextBox2 'default: 4 U(~+o End Dialog ~y=T5wt Dim dlg As UserDialog Gt9&)/# 9x,RvWTb ok = Dialog (dlg) ^C2\`jLMY [+O"<Ua If ok=0 Then 'cancel button was pressed 5 ae2<Y= Print "Execution cancelled." pr%nbl End y%
:4b@< End If E=){K lu Q~YjH 'Assign accommodation and pupil diameter & use defaults if field left empty ~]ZpA-*@Ut If dlg.TextBox1 = "" Then wAnb
Di{W A = 0 'Default accommodation =8U&[F Else H'Yh2a`!o A = CDbl(dlg.TextBox1) n3J53| %v End If CI3XzH\IX* J\e+}{ If dlg.TextBox2 = "" Then AT5aDEb^^ pupilDiam = 4 'Default pupil diameter DTWD|M Else iNMx"F0r pupilDiam = CDbl(dlg.TextBox2) Tw + End If Nk {XdrY +F
dB ' Print " " m3o,@=b Print "Accommodation = " & A & " Diopters" LjV]0%j?r Print "Pupil Diameter = " & pupilDiam & " mm" $s<Ne{? DBLO|&2!z[ ' Calculate new parameters with accommodation .*elggM taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness xe/( *Q1~S]g Rant = 12.0 - 0.4*A 'Radius of anterior lens aL\nT XakX CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens p!s}=wI` c'*a{CV4P Rpost = -5.224557 + 0.2*A 'Radius of posterior lens \>Efd CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 6oui]$pH EUIIr4] tlens = 3.767 + 0.04*A 'Lens thickness V2N_8)s9W 3"F`ZJ]= nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ETB6f !t i6 'Adjust parameters to account for accommodation TRsE % 37;$-cFE '************************************************************************* 7
[g/TB 'Aqueous thickness (Position of Lens) <8,cuX\ '************************************************************************* @)K%2Y` eID = FindFullName( "Geometry.Arizona Eye.Lens" ) L<fvKmo(fw GetCustomElement eID, entity je]}R>[r5 x\QY@9 parID = FindFullName( "Geometry.Arizona Eye" ) o=nsy]'& Xt#1Qs ' Delete any shift(s) in z '?({;/L count = 0 Q[#vTB$f While GetOperationCount(eID)>count ntmyNf?; GetOperation eID, count, op ^Idle*+ If op.Type="ShiftZ" Then Vx @|O% DeleteOperation eID,count $y
b4xU count=count-1 g(#f:" End If [V}S<Xp count=count+1 . BiCBp< Wend uPniLx\t: A19;1#$= 'Set new shift in O iFS}p
op.Type = "ShiftZ" Kt(-@\)! op.val1 = taq >"Q@bQ:e op.parent = parID z~A]9|/61v AddOperation eID, op ;*,f< Print "Set aqueous humor thickness = " & taq-0.55 pAk/Qxl3eo JH8zF{? '************************************************************************* Dr6A,3B 'Radius and conic constant of anterior lens 8|$3OVS '************************************************************************* Oez>X=Xf eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) +d|mR9^([ GetConic eID, entity, curv, conic qgDRu ]ba [}fv dW SetConic eID, entity, 1/Rant, CCant 'FYJMIs Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant *OyHHq|>q 5[Pr|AY '************************************************************************* !\g+8> 'Radius and conic constant of posterior lens xai4pF-? '************************************************************************* M|] "W eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) bb
d. GetConic eID, entity, curv, conic )*:`':_a GHmv}
Z SetConic eID, entity, 1/Rpost, CCpost K).n.:vYZ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ~ Uo)0 TFuR@KaBR '************************************************************************* OaL\w
D^ 'Lens thickness (Position of posterior lens surface) \.g\Zib ) '************************************************************************* ;vb8G$ kQ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,<2DLp%%D Zo{$ ' Delete any z-shift(s) ce6__f5? count = 0 \8uIER5) While GetOperationCount(eID)>count vip~' GetOperation eID, count, op D?Ux[O zb If op.Type="ShiftZ" Then pNRk.m] DeleteOperation eID,count |{@FMxn|q count=count-1 n k2om$nN End If p7H3J?`w1+ count=count+1 ?^j^K-rx Wend 4BwQA#zE IMk'#) 'Set new z-shift b9XW9O`B op.Type = "ShiftZ" |g3?y/l op.val1 = tlens R
CkaJ3 op.parent = parID w4LScvBg AddOperation eID, op %2V-~.Ro6 Print "Set lens thickness = " & tlens hTbI -u7BF Oq3A#6~ '************************************************************************* nQGQWg` 'Lens index of refraction sm$(Y.N '************************************************************************* )3h^Y=43 eID = FindMaterial( "Lens" ) K|oacOF9 GetModelMaterial eID, mat d`1I".y |!F5.%PY mat.Nd = nlens g&n )fF SetModelMaterial eID, mat p^iRPI Print "Set lens index of refraction = " & nlens 3 R&lqxhg wd/<
8>2X '************************************************************************* . <tq61 'Pupil diameter b}Zd)2G '************************************************************************* q:<{% U$ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 4Bl{WyMJ | |7#[ (%D! 'Adjust pupil diameter (trimming volume inner hole) J6<rX[
yZe Z;h<6[( SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" S(mF%WJ `EtS!zD~b ' Adjust pupil location to just in front of the lens &[&r2>a parID = FindFullName( "Geometry.Arizona Eye" ) 0cT*z( eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) B(F,h+ajy count = 0 KzQ3.)/q While GetOperationCount(eID)>count *|_"W+JC GetOperation eID, count, op 9h0X &1u If op.Type="ShiftZ" Then .SWt3|Pi5 DeleteOperation eID,count ,j 5&6X=1M count=count-1 cT\I[9!) End If Gy[O)PEEh count=count+1 we#wH- Wend (Y^X0yA/ op.Type = "ShiftZ" IL_d:HF|1 op.val1 = taq-0.01 ~y$ !48o op.parent = parID F,5r9^,_ AddOperation eID, op Ys!>+nL| %AN/>\#p Print "Set pupil diameter = " & pupilDiam u`(-
- Z#.f&K )xX 'Update AZ Eye subassembly Description Jdy=_88MD
eID = FindFullName( "Geometry.Arizona Eye" ) +w8R!jdA GetEntity eID, entity CU7F5@+ entity.Description = "Accommodation = " & A & "D" j|tC@0A SetEntity eID, entity <|?K%FP7Z +ki{H}G21 Update fw; rbP! Print "DONE!" KgW:@X7wvM ~r{5`;c End Sub ?`[NFqv_] Bb{!Yh].:A 如果屈光度是4,光瞳直径是4,则会输出如下数据: T}3v(6ew4 P_u|-~|\ Accommodation = 4 Diopters V]S1X^ Pupil Diameter = 4 mm 1T)Zh+?)} Set aqueous humor thickness = 2.81 M. td^l0 Set anterior lens radius = 10.4 and conic constant = -2.375869 8_K60eXz Set posterior lens radius = -4.424557 and conic constant = -3.081019 B??J@+Nf Set lens thickness = 3.927 ""svDfy$ Set lens index of refraction = 1.42672 gGMWr.!
8 Set pupil diameter = 4 ,p;_\\< DONE! RmI1`
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