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简介 u . xUM yGxAur=dE 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。 @PaOQ@ WRBCNra 模型 -E$(<Pow~\ i7%v2_ 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 ~$WBc qo /.1yxb#Z?, Table 1. AZ眼睛模型的定义 Xxz_h* 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. l\HLlwYO YQH=]5r 光源 DL t "cAW ,:E*Mw: 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。 <Lt%[dn /O^aFIxk uZg[PS=@!X 图1. 光源和提示信息使用 dr[sSBTY" 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。 Fx3CY W U5iyvU=UG 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。 tbH`VD"u yMd<<:Ap 图2. 字母F光源的设定方法光 or8`.hEHI v7h!'U[/ 图3. 字母F在视网膜上位置点列图 6XFLWN-) 视网膜的散射 PXx:JZsju B%.vEk)* 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。 a7?)x])e [J{M'+a Q|6lp 图4. 视网膜朗伯散射设定 PX} ~ 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。 S.I3m- -PG81F&K vOIzfwYG9 图5. 视网膜重点采样规格设定 |*T`3@R;3 脚本 _oILZ, @mJ#~@*( 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: )Z" Jn#05Z 图6. 用户对话框的创建与编辑 R/O>^s!Co 图7. 用户对话框编辑器 N|N#- 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。 dPm_jX 余下的脚本计算与屈光度有关的所有参数。 M SnRx*- HkL:3 E. 分析 }3TTtd7 ^E#i5d+'N 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 C9FzTg/c Bn<1zg5 图7. 字母F在视网膜上颜色分析 9'5`0$,|^ 脚本代码 blk4@pg ,bGYixIfYZ Option Explicit 'Remove this to enable non-dimensioned variables to be used. Sc/\g SZ&I4- Dim entity As T_ENTITY okkMx" Dim op As T_OPERATION #3_t}<fX Dim mat As T_MODELMATERIAL y!kU0 Dim A As Double m+a\NXWR?N Dim pupilDiam As Double ( Ev=kO Dim eID As Long J6C/`)+w Dim parID As Long _no;B_m~ Dim count As Integer DTMoZm Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double fN!lXPgM Dim tlens As Double, nlens As Double y[64O x Dim curv As Double, conic As Double (oxMBd+n1 Dim ok As Long ;_oJGII?br 0|=,!sY Sub Main y(fJ{k *I6W6y;E= '用户输入对话框 +I>V9%%vW_ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 !j8
DCVb TextBox 220,21,40,21,.TextBox1 'default: 0 ^Mm sja5K Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 QUO'{;, OKButton 40,91,90,21 iU/v;T( CancelButton 190,91,90,21 &*YFK/ ] Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 v[+ ] TextBox 220,49,40,21,.TextBox2 'default: 4 8JFvz(SK> End Dialog Gv+$7{ Dim dlg As UserDialog EZee
kxs 1va~.;/rG ok = Dialog (dlg) k5@PZFV !zZ3F|+HB If ok=0 Then 'cancel button was pressed )#Le"&D Print "Execution cancelled." ]/6i#fTw End R8%%EEB End If "sU jJ| }Sr=|j 'Assign accommodation and pupil diameter & use defaults if field left empty n|N?[)^k If dlg.TextBox1 = "" Then bn#'o(Lp A = 0 'Default accommodation =3dR-3 Else mFgrT A = CDbl(dlg.TextBox1) @QO^3%b8 End If tu:W1? hCPyCq] If dlg.TextBox2 = "" Then A:4?Jd> pupilDiam = 4 'Default pupil diameter 0CpE,gg Else k~XDwmt; pupilDiam = CDbl(dlg.TextBox2) cfC}"As End If (&!RX.i x+8%4]u` Print " " Mc9J Fzp Print "Accommodation = " & A & " Diopters" <f9a%`d Print "Pupil Diameter = " & pupilDiam & " mm" .2{*>Dzi =oT4!OUf ' Calculate new parameters with accommodation HJ+Q7) taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ;wa#m1 CxD=8X9m Rant = 12.0 - 0.4*A 'Radius of anterior lens
1}Th@Vq CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 9U4 D$M :ggXVwpe Rpost = -5.224557 + 0.2*A 'Radius of posterior lens {HtW`r1)Tt CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens TXS{= PS3jCT tlens = 3.767 + 0.04*A 'Lens thickness Vj[hT~{f KsSIX nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction bk|?>yd ~5>k_\G8 'Adjust parameters to account for accommodation JLak>MS Ke^9R-jP '************************************************************************* &>xz 'Aqueous thickness (Position of Lens) 64qqJmG3 '************************************************************************* t"nxny9& eID = FindFullName( "Geometry.Arizona Eye.Lens" ) RpwDOG GetCustomElement eID, entity KU^|T2s% S1o[)q
parID = FindFullName( "Geometry.Arizona Eye" ) j;J`PH -
VdCj%r> ' Delete any shift(s) in z ~wQ M
?h count = 0 M=54xTh0Y While GetOperationCount(eID)>count NpH9},1i GetOperation eID, count, op :;jRAjq" If op.Type="ShiftZ" Then kjF4c6v DeleteOperation eID,count TF?~vS%@P count=count-1 K SJ Ko End If '?Xf(6o1 count=count+1 5fy{! Wend NQcNY= aZ8f>t1Q 'Set new shift in c-* *~tb( op.Type = "ShiftZ" B9wQ;[gQB op.val1 = taq T>|Y_3YO_a op.parent = parID N , ,[V
AddOperation eID, op x~ID[ Print "Set aqueous humor thickness = " & taq-0.55 u
s8.nL/ Gi\Z"MiBZ '************************************************************************* 8~sC$sIlE 'Radius and conic constant of anterior lens 2O}X-/H '************************************************************************* Rh%A^j@ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) .I]EP- GetConic eID, entity, curv, conic 7-
|N&u -^JPY)\R SetConic eID, entity, 1/Rant, CCant RG 9iTA' Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant sB!6"D5 IdCE<Oj\ '************************************************************************* JkQ\r$Y. 'Radius and conic constant of posterior lens G!Yt.M0 '************************************************************************* %I;uqf eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) &79F
Uac GetConic eID, entity, curv, conic b3ys"Vyn Js(MzL SetConic eID, entity, 1/Rpost, CCpost U ]7;K>.T Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Z&n#*rQ7[ :o:Z '************************************************************************* NU"L1dK
@ 'Lens thickness (Position of posterior lens surface) [OS&eK 8 '************************************************************************* t]T't=' &[
,* parID = FindFullName( "Geometry.Arizona Eye.Lens" ) rP#&WSLVj >-y}t9[/ ' Delete any z-shift(s) 8Y_lQfJa count = 0 \wR\i^ While GetOperationCount(eID)>count wScr:o+K>L GetOperation eID, count, op cUO$IR)yL If op.Type="ShiftZ" Then 3_>=Cv} DeleteOperation eID,count tF\_AvL_8 count=count-1 R[rOzoNp0 End If gX|\O']6 count=count+1 \(}pm#O Wend q3`~uTzk q{+}0!o 'Set new z-shift >>cL"m op.Type = "ShiftZ" 1@9M[_<n5 op.val1 = tlens 6n;? :./ op.parent = parID mC3:P5/c AddOperation eID, op Qn.3B Print "Set lens thickness = " & tlens f ~bgZ h
gu\~}kD '************************************************************************* ^])s\a$ 'Lens index of refraction t#%J=zF{ '************************************************************************* !}sF# eID = FindMaterial( "Lens" ) v5&W)F GetModelMaterial eID, mat \Y`psSf+ qTN30(x2 mat.Nd = nlens s#(7D3Pr# SetModelMaterial eID, mat N,.awA{ Print "Set lens index of refraction = " & nlens IJC]Al,df ["e;8H[K)% '************************************************************************* wr~Qy4 ny 'Pupil diameter /B|"<`-H '************************************************************************* Asy2jw\V eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) q\<NW%KtX x3F94+<n{ 'Adjust pupil diameter (trimming volume inner hole) QU(Lv(/O phB d+zQc SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" u68ic1 t^}"8 ' Adjust pupil location to just in front of the lens D[6wMep^n parID = FindFullName( "Geometry.Arizona Eye" ) f0YBy<a eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 0#ON}l)> count = 0 #4!f/dWJp While GetOperationCount(eID)>count lTVz'ys GetOperation eID, count, op $e.Bz` If op.Type="ShiftZ" Then Vy^mEsQC+h DeleteOperation eID,count %Aa_Bumf*: count=count-1 "ZA`Lp;%w End If j,Qb'|f5 count=count+1 1#8~@CQ :: Wend kWs:7jiiu op.Type = "ShiftZ" q^7=/d8 op.val1 = taq-0.01 d*=qqe
H op.parent = parID +UX}
"m~W AddOperation eID, op ~}SQLYy7Z = )4bf"~8 Print "Set pupil diameter = " & pupilDiam wUfPnAD.' r"p"UW9og 'Update AZ Eye subassembly Description JvaHH!>d/ eID = FindFullName( "Geometry.Arizona Eye" ) RWoVN$i> GetEntity eID, entity BqdGU-Q entity.Description = "Accommodation = " & A & "D" QUg<~q)Oq SetEntity eID, entity L`fT;2 nA%8
bZ+ Update Y&y<WN}Q Print "DONE!" vV*/"'> `6LVXDR End Sub ldc`Y/:{ wo$ F_!3u 如果屈光度是4,光瞳直径是4,则会输出如下数据: AgB$
w4 =$ubSfx Accommodation = 4 Diopters woN
d7`C}7 Pupil Diameter = 4 mm 6Q&i=!fQ Set aqueous humor thickness = 2.81 4{b/Nv:b Set anterior lens radius = 10.4 and conic constant = -2.375869 :5jor Vu Set posterior lens radius = -4.424557 and conic constant = -3.081019 V#c=O} Set lens thickness = 3.927 =/4}!B/ Set lens index of refraction = 1.42672 xsrdHP1 Set pupil diameter = 4 rP/W,!
7:K DONE! BZjL\{IW A5O; C `8TL*.9 QQ:2987619807 JD AX^]
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