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简介 a\Dw*h?b~ i2n66d 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。 LGPg\g` ~0Xx] 模型 xoNn'LF#u sH\ h{^ 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。 #4ii!ev ){xMMQ5 Table 1. AZ眼睛模型的定义 @rxfOc0J# 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. S")*~)N@ s]i<D9h 光源 JbW!V Y psB9~EU&Q 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。 sr`)l& t? 7K &j ~+O ws 图1. 光源和提示信息使用 {iq)[)n 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。 z|sR
`]K zq4)Uab* 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。 fg~9{1B )*_n/^m 图2. 字母F光源的设定方法光 t$5)6zG T.iVY5^< 图3. 字母F在视网膜上位置点列图 G,A;`:/ 视网膜的散射 M;1B}x@ H"%SzU 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 If%**o :y(HOUB O
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X 图4. 视网膜朗伯散射设定 >}>cJh6 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 Xsv^GmP+ n<66 7
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k+nD 图5. 视网膜重点采样规格设定 AX2On}&bf 脚本 F)4;:".zna j[\aGS7u 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: -
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@"@kbr 图6. 用户对话框的创建与编辑 WU<C7 图7. 用户对话框编辑器 .GNl31f0 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 Gt5'-Hyo 余下的脚本计算与屈光度有关的所有参数。 ICXz(?a yZ57uz 分析 p/.[cH ^+q4* X6VB 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 {B+{2;Zk zHW}A
`Rz 图7. 字母F在视网膜上颜色分析 {_1zIt| 脚本代码 WbDD9ZS PvB-Cqc Option Explicit 'Remove this to enable non-dimensioned variables to be used. ;mLbgiqQ J LwS>jNJx Dim entity As T_ENTITY {1]/ok2k5 Dim op As T_OPERATION C4/p5J Dim mat As T_MODELMATERIAL %<Te&6NU' Dim A As Double u!K5jqP Dim pupilDiam As Double l/o
4bkV Dim eID As Long e-/+e64Q@ Dim parID As Long 3rQ;}<*M Dim count As Integer @$%[D`Wa< Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ECEDNib Dim tlens As Double, nlens As Double =pR'XF% Dim curv As Double, conic As Double p:q?8+W-r Dim ok As Long Uv"O'Z E<
Ini'od[ Sub Main lVc':,z u+/1ryp '用户输入对话框 H@!kgaNF Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Wo8.tu-2 TextBox 220,21,40,21,.TextBox1 'default: 0 NgPY/R> Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 @&LtIN# OKButton 40,91,90,21 A%dI8Z, CancelButton 190,91,90,21 FW7@7cVoF Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1
*^b<CZd9 TextBox 220,49,40,21,.TextBox2 'default: 4 wUBug End Dialog zM*PN|/%sH Dim dlg As UserDialog { WW!P,w li
Hz5<| ok = Dialog (dlg) *{e?%!Q 5u3SP?.& If ok=0 Then 'cancel button was pressed o?\v
8.n Print "Execution cancelled." )/2J|LxS End Af%#&r7W End If nt*nTtcE 4ZN&Yf` 'Assign accommodation and pupil diameter & use defaults if field left empty m? #J`?E If dlg.TextBox1 = "" Then :ncR7:Z A = 0 'Default accommodation jVhfpS[ Else
;'g.% A = CDbl(dlg.TextBox1) {s/u[T_D2 End If `lA[-x~ ); <Le6 If dlg.TextBox2 = "" Then iS%md pupilDiam = 4 'Default pupil diameter ^~:&/ 0 Else 1}"PLq( pupilDiam = CDbl(dlg.TextBox2) pJpTOq\h End If W
n43TSs- ?}g#Mc Print " " `zZGL&9m` Print "Accommodation = " & A & " Diopters" 6EeK5XLf, Print "Pupil Diameter = " & pupilDiam & " mm" ij/5m-{6) !tL&Ktoj ' Calculate new parameters with accommodation ]fgYO+ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness -w#Hy>E PC3-X['[ Rant = 12.0 - 0.4*A 'Radius of anterior lens hd E? %A CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens '7Aj0U( IFg(Ze~ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens e//q`?ys CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens MH8 Selnv _x ;fTW0 tlens = 3.767 + 0.04*A 'Lens thickness b=-LQkcZhK qIIl,!&}A nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction hz8Z)xjJ V lh?TEQ 'Adjust parameters to account for accommodation oA1d8*i^E 9/nS?>11 '************************************************************************* DKGZm<G> 'Aqueous thickness (Position of Lens) 7<ZCeM2x '************************************************************************* $sX X6K), eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6+;B2;*3 GetCustomElement eID, entity Ao/KB_4f*Q IT~pp_6g parID = FindFullName( "Geometry.Arizona Eye" ) Gap\~Z@L O)4P)KAO< ' Delete any shift(s) in z i[wEH1jR count = 0 /EpsJb`kj While GetOperationCount(eID)>count u3>Dvl@ GetOperation eID, count, op [x.DwU%S If op.Type="ShiftZ" Then x$'0}vnT DeleteOperation eID,count gqi|k6V/ count=count-1 \?X'U: End If , Q5Z<\
count=count+1 D`G ;kp Wend cI Byv I- l"-F<^
U 'Set new shift in IO4 8sV } op.Type = "ShiftZ" ct3^V M&/ op.val1 = taq zU7/P|Dw+ op.parent = parID N){/#3 AddOperation eID, op sP+ZE>7 Print "Set aqueous humor thickness = " & taq-0.55 3;h%mkKQ+ [7:(e/& '************************************************************************* q ["T6 'Radius and conic constant of anterior lens e{dYLQd '************************************************************************* {{\
d5CkX eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) y,`SLgBID GetConic eID, entity, curv, conic EZ.|6oug\ kZsat4r SetConic eID, entity, 1/Rant, CCant {J}Zv5 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant u{-J?t&` =[$zR>o*% '************************************************************************* ?5> Ep:{+/ 'Radius and conic constant of posterior lens {'QA0K '************************************************************************* U6pG eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 1gZW~6a} GetConic eID, entity, curv, conic m'Thm{Y,?n ^nS'3g^" SetConic eID, entity, 1/Rpost, CCpost O'G, Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost $g?`yE(K Yzr|Z7rq} '************************************************************************* Zu$30&U 'Lens thickness (Position of posterior lens surface) 'WA]DlO '************************************************************************* Q0}Sju+HX B tZycI parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2[Ja|W\If "s6O|=^* ' Delete any z-shift(s) %e@Jc3 count = 0 sKkk+-J4 While GetOperationCount(eID)>count W+'|zhn GetOperation eID, count, op /kAu&} If op.Type="ShiftZ" Then 3+%c*}KC~ DeleteOperation eID,count .!\NM&E count=count-1 jM E==)Y End If <]u~;e57 count=count+1 ]Y%?kQ^ Wend <oE(I)r4, %Q}T9%Mtj 'Set new z-shift O%(E 6
n op.Type = "ShiftZ" Wa8?o~0"L op.val1 = tlens O=HT3gp& op.parent = parID }538vFNi AddOperation eID, op ;n9r;$!f Print "Set lens thickness = " & tlens QzwA*\G Z.Sq5\d '************************************************************************* ?E@9Nvr 'Lens index of refraction 7,sslf2%K '************************************************************************* LV:`siK eID = FindMaterial( "Lens" ) >lo,0oG GetModelMaterial eID, mat kT!Y~c \`|*i$ mat.Nd = nlens #8!xIy SetModelMaterial eID, mat -N')LY Print "Set lens index of refraction = " & nlens mgB7l0)b QT;mCD=OD '************************************************************************* v.08,P{b 'Pupil diameter _$+lyea '************************************************************************* u |hT1l eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) xp395ub6 2qb,bp1$ 'Adjust pupil diameter (trimming volume inner hole) l3sL!D1u ^<0azza/( SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" \X=?+|
9 IT3xX=|b ' Adjust pupil location to just in front of the lens xwwy9:ze*l parID = FindFullName( "Geometry.Arizona Eye" ) +v 9@du eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) yW&|ZJF? count = 0 nyZUf{: While GetOperationCount(eID)>count 26YY1T\B) GetOperation eID, count, op %|l^oC+E If op.Type="ShiftZ" Then /
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kNy DeleteOperation eID,count <c[+60p" count=count-1 AwhXCq|k End If ,cR=W|6cQm count=count+1 MCOz-8@|Y Wend I/ pv0 op.Type = "ShiftZ" 3[RbVT op.val1 = taq-0.01 %)7HBj(*J op.parent = parID ;:nO5VFOg AddOperation eID, op N 798(" `TM[7' Print "Set pupil diameter = " & pupilDiam N7=L^] T@[(FVA N 'Update AZ Eye subassembly Description 2=3pV!)4} eID = FindFullName( "Geometry.Arizona Eye" ) Fm@G@W7,m GetEntity eID, entity {L[n\h.4. entity.Description = "Accommodation = " & A & "D" qM(n]{H SetEntity eID, entity 2Uf}gG) ':kj\$U Update #>m#i1Nu Print "DONE!" i-(^t1c 8Y.25$ End Sub #C+""qm 6Q&R,"!$p 如果屈光度是4,光瞳直径是4,则会输出如下数据: . Q3GA0O `!?SA<a: Accommodation = 4 Diopters 6{rH|Z Pupil Diameter = 4 mm 7/.- dfEK Set aqueous humor thickness = 2.81 9kcp( Set anterior lens radius = 10.4 and conic constant = -2.375869 zG_e= Set posterior lens radius = -4.424557 and conic constant = -3.081019 t_@xzt10y Set lens thickness = 3.927 >gAq/'.Q Set lens index of refraction = 1.42672 Sb=cWn P Set pupil diameter = 4 J1I"H<}-6 DONE! .6Swc?
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