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简介 n^qwE 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。 '< >Q20 `s=Z{bw 模型 D]'8BS3 `GY]JVW 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。 e_rEu'[av {Ngut Table 1. AZ眼睛模型的定义 u~'_Uqp 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. tv`c"Pb "_BWUY 光源 %7\l+g, +>u 8r&Jw. 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。 |vG?H#y D^];6\=.i pD~."fb 图1. 光源和提示信息使用 5yV>-XT+- 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。 C\bJ_vl;' 4@ny%_/ 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。 M#8_Qbvfk o:as}7/^ 图2. 字母F光源的设定方法光 DI-CC[ HG5E,^1n 图3. 字母F在视网膜上位置点列图 `!ja0Sq]U 视网膜的散射 2*n~r K^b'<} $|p 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 mv$gL /6 x[C {=3'H?$ 图4. 视网膜朗伯散射设定 wIF'|" 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。 }^n"t>Z8 #&K}w0}k Fs=E8' b 图5. 视网膜重点采样规格设定 *J4\KU 脚本 =|^R<#%/ ?c fFJl 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: 0NvicZ7VR
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kj4Jf 图6. 用户对话框的创建与编辑 {p(6bsn_#] 图7. 用户对话框编辑器 9r8bSV3` 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。 6s!=de 余下的脚本计算与屈光度有关的所有参数。 ^O"o-3dte z<.6jx@ 分析 g+4x {HVsRpNEf 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 zx?|5=+! n2'XWbMaL 图7. 字母F在视网膜上颜色分析 Je K0>< 脚本代码 S1i~r+jf kidv^`.H$w Option Explicit 'Remove this to enable non-dimensioned variables to be used. m^tf=O< #Qu|9Q[QH Dim entity As T_ENTITY 9wC=' Dim op As T_OPERATION PvxU. Dim mat As T_MODELMATERIAL VZk;{ Dim A As Double ]<_v;Q<t Dim pupilDiam As Double Qgo|\= Dim eID As Long _2}/rwVg Dim parID As Long Z?eedVV@ Dim count As Integer B/JMH 1r Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double
}[;r-5} Dim tlens As Double, nlens As Double M=5hp&= Dim curv As Double, conic As Double .&KC2#4 Dim ok As Long 7U&<{U< NV2$ >D Sub Main @Ps1.
G98f Bw '用户输入对话框 EM'#'fBZ>Y Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Z =*h9,MY TextBox 220,21,40,21,.TextBox1 'default: 0 `TDS4Y Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 "haJwV6- OKButton 40,91,90,21 u6*0%
Km CancelButton 190,91,90,21 LdX'V]ITh Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 v dU) TextBox 220,49,40,21,.TextBox2 'default: 4 0 \o5+ End Dialog 7wbpQ&1_ Dim dlg As UserDialog CG!9{&F aq^OzKP? ok = Dialog (dlg) ^8g<>,$ 1#vi]CX If ok=0 Then 'cancel button was pressed [](] "r Print "Execution cancelled." OI^qX;#Kd End zhI"++ End If i6:O9Km %hRH80W| 'Assign accommodation and pupil diameter & use defaults if field left empty RJD(c#r$ If dlg.TextBox1 = "" Then 6[a;83 A = 0 'Default accommodation -9q3]nmT( Else VzuU0 A = CDbl(dlg.TextBox1) G mmh&Uj End If uNvdlY] 6J3<k(#: If dlg.TextBox2 = "" Then {jEEAH) pupilDiam = 4 'Default pupil diameter x 4`RKv2m Else *XG.?%x*| pupilDiam = CDbl(dlg.TextBox2) W`jKe-jF End If kcl Z+E $1|65j[e Print " " z3|5E#m Print "Accommodation = " & A & " Diopters" ~Z;.np(T Print "Pupil Diameter = " & pupilDiam & " mm" Ce@"+k+w 7@ !3.u1B ' Calculate new parameters with accommodation ]l=iKl taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 4{ED~w|
4{D^ 4G Rant = 12.0 - 0.4*A 'Radius of anterior lens ua%j}%G( CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens tAS[T9B rCdTn+O2 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Tl-Ix&37 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 7,R
~2ss5z XWUi_{zn tlens = 3.767 + 0.04*A 'Lens thickness LP//\E_] b}m@2DR'|m nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction RnUud\T/ 249DAjn+ 'Adjust parameters to account for accommodation d+IN-lR( u
236a\: '************************************************************************* ,o6,(jJU 'Aqueous thickness (Position of Lens) idY
Xv)R '*************************************************************************
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N eID = FindFullName( "Geometry.Arizona Eye.Lens" ) VJ-To} GetCustomElement eID, entity E-HK=D&W/ "V<7X%LIX parID = FindFullName( "Geometry.Arizona Eye" ) S+-V16{i 'M%uw85 ' Delete any shift(s) in z g"X!&$& count = 0 Q6%Pp_$k While GetOperationCount(eID)>count &B} ,xcNO GetOperation eID, count, op LOe l6Ui If op.Type="ShiftZ" Then ~{{@m]P DeleteOperation eID,count Ihx[S!: count=count-1 Gs(;&fw End If Y?JB%%WWI count=count+1 zB#.EW Wend C&RZdh,$ W$Z8AZ{E 'Set new shift in 18ON`j op.Type = "ShiftZ" d+&w7/F op.val1 = taq (bGk=q=M op.parent = parID WTu1t] AddOperation eID, op |:Lk lpdYe Print "Set aqueous humor thickness = " & taq-0.55 kC/An@J^# MZdj!(hO '************************************************************************* BYb"[qPV 'Radius and conic constant of anterior lens {R5_=MG '************************************************************************* w)"F=33}5 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) zKNac[: GetConic eID, entity, curv, conic r/RX|M 9PJnKzQ4 SetConic eID, entity, 1/Rant, CCant dIk9C|-. Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant co>IJzg [lE^0_+ '************************************************************************* snyA 'Radius and conic constant of posterior lens /O[Z '************************************************************************* `/o| 1vv@_ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) #[sJKW GetConic eID, entity, curv, conic $~'G<YYF4 dG}*M25 SetConic eID, entity, 1/Rpost, CCpost fY 10a_@x Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost cs)R8vuB)z >\!k~Zi '************************************************************************* *xDV8iu_ 'Lens thickness (Position of posterior lens surface) :qtg `zM/4 '************************************************************************* FQ]5W |e <P-AlHYV- parID = FindFullName( "Geometry.Arizona Eye.Lens" ) XZj3x',; f:ep~5] G ' Delete any z-shift(s) ])vqXjN6" count = 0 Kj#h9e While GetOperationCount(eID)>count Eg$Er*)h8 GetOperation eID, count, op /D;cm If op.Type="ShiftZ" Then iy|xF~ DeleteOperation eID,count 6\6g-1B` count=count-1 ,sltB3f End If {"\pMY'7 count=count+1 P7;q^jlB Wend z=qxZuFkDs VaTA|=[; 'Set new z-shift xhncQhf\ op.Type = "ShiftZ" 'o1lJ?~kH op.val1 = tlens kDc/]Zb% op.parent = parID cEEnR1 AddOperation eID, op X'usd$[. Print "Set lens thickness = " & tlens |i- S}M 5[H1nC
@C '************************************************************************* W
ZW:q 'Lens index of refraction +(oExp(! '************************************************************************* zu``F]B eID = FindMaterial( "Lens" ) ^aY,Wq GetModelMaterial eID, mat P8GGN a-9sc6@ mat.Nd = nlens K#]FUUnj= SetModelMaterial eID, mat %wIb@km Print "Set lens index of refraction = " & nlens hu:x,;`9H oC(.u ? '************************************************************************* C40W@*6S2 'Pupil diameter m<|fdS'@ '************************************************************************* ^PowL: eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 3q`Uq`t4mR 3s_$. 'Adjust pupil diameter (trimming volume inner hole) H@`lM~T[ )D
':bWP SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" gOk um_ =_`cY^ib+ ' Adjust pupil location to just in front of the lens @0iXqM#jH parID = FindFullName( "Geometry.Arizona Eye" ) 6R!AIOD> eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 8%^W<.Y count = 0 Lg+cHaA While GetOperationCount(eID)>count (sEZNo5 n GetOperation eID, count, op 5hp)Z7 If op.Type="ShiftZ" Then +$B#] , DeleteOperation eID,count 9HD 5A$ count=count-1 d&%}u1 . End If tdnd~ WSR count=count+1 =[`gfw Wend -<^3!C > op.Type = "ShiftZ" 3 /LW6W| op.val1 = taq-0.01 :bz;_DZP op.parent = parID }*56DX AddOperation eID, op ~0Mw\p%} JO\KTWtjO Print "Set pupil diameter = " & pupilDiam ilFS9A3P T_~xDQ` v 'Update AZ Eye subassembly Description P.O/ZW>g eID = FindFullName( "Geometry.Arizona Eye" ) N-}|!pqb GetEntity eID, entity Vet<,;Te entity.Description = "Accommodation = " & A & "D" zA@w[. SetEntity eID, entity `
NWmwmWB" Ir3|PehB Update ux>LciNq Print "DONE!" | @p Px?0)^"2 End Sub 2G}@s.iE .
"`f~s\G 如果屈光度是4,光瞳直径是4,则会输出如下数据: wO"ezQ 2m2$jp0 Accommodation = 4 Diopters TV(%e4U= Pupil Diameter = 4 mm !&Us^Q^ Set aqueous humor thickness = 2.81 +!"7=?} Set anterior lens radius = 10.4 and conic constant = -2.375869 (t"rzH Set posterior lens radius = -4.424557 and conic constant = -3.081019 s7:w>,v/ Set lens thickness = 3.927 'z">4{5 Set lens index of refraction = 1.42672 5S&^mj-9 Set pupil diameter = 4 10$:^ DONE! :6}cczQE|O W29GM -,K (文章来源:讯技光电)
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