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简介 s!RA_%8/> R(Pa Q 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。 zxmI/]3+/ )LMuxj 模型 `]I5WTt*X NCpn^m)Q} 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。 8&[<pbN) [<1+Q =; Table 1. AZ眼睛模型的定义 X\)KVn` 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. H?bsK~ tJF~Xv2L! 光源 Z.OrHg1 TdOWdPvYj 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。 d`][1rZk +jZg%$Q!# 7D_kkhN 图1. 光源和提示信息使用 T9v#Jb6 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 A VG`r2T 'oeg[ 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 +
d)~;I$ |[7$) $ 图2. 字母F光源的设定方法光 X^ ]$/rI) -oT+;2\2 图3. 字母F在视网膜上位置点列图 3S|;yOl#X 视网膜的散射 v2=!* J9t? ]9.,: 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。 r!gCh`PiK 3EX&.OL! %1+~(1P 图4. 视网膜朗伯散射设定 $P9$ ,w4 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。 QgM_SY|Rj Wk#-LkI V~"d`j 图5. 视网膜重点采样规格设定 R6o<p<fTh 脚本 &fhurzzAm r&~iEO|?\ 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: dnc!=Z89 _llaH 图6. 用户对话框的创建与编辑 2s ,n!u
Fd 图7. 用户对话框编辑器 y:zT1I@> 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。 b'"% 余下的脚本计算与屈光度有关的所有参数。 -"fq34v [ +@<T) 分析 zk~ rKQ, |3o@IuGt 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 BFu9KS+@) `l#$l3v+ 图7. 字母F在视网膜上颜色分析 yj9gN}+ 脚本代码 )L("t Z"KuS Option Explicit 'Remove this to enable non-dimensioned variables to be used. 5Cka."bQ /s_$CSiB Dim entity As T_ENTITY pg`;)@ Dim op As T_OPERATION +-137!x\q Dim mat As T_MODELMATERIAL B y8Tw;aL Dim A As Double +Z0E?,Oz Dim pupilDiam As Double {oeQK Dim eID As Long $466?
oI Dim parID As Long .]l2)OlLQ Dim count As Integer 7B :aJfxM Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 1k({(\>qq Dim tlens As Double, nlens As Double
`.-C6! Dim curv As Double, conic As Double 'F~SNIay Dim ok As Long OyZ>R~c'B pD/S\E0@t Sub Main f|E'eFrFk v> PHn69PU '用户输入对话框 CU&,Kq@ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 t!C-G+It TextBox 220,21,40,21,.TextBox1 'default: 0
kS9 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 $QnfpM%+= OKButton 40,91,90,21 m<ruFxY CancelButton 190,91,90,21 7[ji,.7 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 \H12~=p`B TextBox 220,49,40,21,.TextBox2 'default: 4 rnaDo\5 End Dialog O,6!`\N D Dim dlg As UserDialog 4w[ta?&6B 4 l(o{{ ok = Dialog (dlg) :UciFIa EHjhez If ok=0 Then 'cancel button was pressed go5!zSs Print "Execution cancelled." =?aB@& End c:T P7"vG End If w!M ^p&T7 -6>rR{z 'Assign accommodation and pupil diameter & use defaults if field left empty -lEh}r If dlg.TextBox1 = "" Then N `MQHQ1 A = 0 'Default accommodation ~`.%n7 Else J n/=v\K@ A = CDbl(dlg.TextBox1) \}W.RQ^3 End If $
7!GA9Bn mYX) =B{ If dlg.TextBox2 = "" Then c5pG?jr+d pupilDiam = 4 'Default pupil diameter (5
hu
W7v Else u>#'Y+7 pupilDiam = CDbl(dlg.TextBox2) (#lS?+w) End If OwUbm0)h^V X=~QE}x Print " " nX'.'3 Print "Accommodation = " & A & " Diopters" !y.7"G* Print "Pupil Diameter = " & pupilDiam & " mm" r>o6}Mx$ :f:C*mYvu ' Calculate new parameters with accommodation Z0KA4O$eL taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness k=}hY+/= 39#>C~BOl Rant = 12.0 - 0.4*A 'Radius of anterior lens Sa5 y7
CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Yw0@O1Cel 0jH2.d= Rpost = -5.224557 + 0.2*A 'Radius of posterior lens O*7
pg CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ,fRb6s- s]UeDZ<a tlens = 3.767 + 0.04*A 'Lens thickness jL&F7itP j*}xe'# nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction j/&7L@Y .CYkb8hF 'Adjust parameters to account for accommodation ]vMft? iDr0_y*t '************************************************************************* `N+ P, 'Aqueous thickness (Position of Lens) Vv]mME@ '************************************************************************* 1)y}.y5S eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Re_.<_$ GetCustomElement eID, entity A[MEtI=Q J A\>qoR!Y parID = FindFullName( "Geometry.Arizona Eye" ) G].Z| Z9 %VCHM GP= ' Delete any shift(s) in z -L@=j count = 0 }<p%PyM While GetOperationCount(eID)>count w'C(? ?mH GetOperation eID, count, op lx SGvvP4 If op.Type="ShiftZ" Then b.(^CYYQ DeleteOperation eID,count I6+5 mv\ count=count-1 fqxMTTg@ End If kmwFw># count=count+1 nM#\4Q[}Jh Wend lUmaNZ hdzaU&w 'Set new shift in f|!zjX` op.Type = "ShiftZ" 8}2
`^<U op.val1 = taq o'G")o op.parent = parID Ex<0@Oz AddOperation eID, op c)?y3LX Print "Set aqueous humor thickness = " & taq-0.55 TD'1L:mv Em;zi.Y+V '************************************************************************* P$Nwf,d2u 'Radius and conic constant of anterior lens V0>,Kxk '************************************************************************* 4?`7XJ0a eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) q-'zZ# GetConic eID, entity, curv, conic tP3Upw"U raCxHY SetConic eID, entity, 1/Rant, CCant @L0.Z1 ). Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant *:iFhKFU 74_ji! '************************************************************************* B4%W,F:@ 'Radius and conic constant of posterior lens ~_Aclm? '************************************************************************* 0[^f9NZ>- eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) :0/I2: GetConic eID, entity, curv, conic !U@[lBW sNWj+T SetConic eID, entity, 1/Rpost, CCpost 0=NB[eG Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost YIfbcR5 yo5|~"yZY '************************************************************************* b$hQB090 'Lens thickness (Position of posterior lens surface) @>?&Mw\c '************************************************************************* (c;$^xZK >Gkkr{s9 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) .M04n\ i9Qx{f88 ' Delete any z-shift(s) ffd yDUzQ count = 0 8D-g%Aj- While GetOperationCount(eID)>count E8/P D GetOperation eID, count, op {B34^H: If op.Type="ShiftZ" Then =4G9ev
4 DeleteOperation eID,count
W<t,Ivg count=count-1 9i n& \ End If N
G4wtDa count=count+1 f -bVcWI Wend P:=3;d{v I%|W
O*x 'Set new z-shift }2}hH0R op.Type = "ShiftZ" tcfUhSz,I op.val1 = tlens |VIBSty2d op.parent = parID t<rhrW75P AddOperation eID, op -YD6 Print "Set lens thickness = " & tlens )]'?yS" (V*ggii@ '************************************************************************* Gt' %:9r 'Lens index of refraction dAR):ZKq? '************************************************************************* +PjH2 eID = FindMaterial( "Lens" ) mjfU[2 GetModelMaterial eID, mat 99vm7"5 hQ S~hNSw(- mat.Nd = nlens ))<3+^S0V\ SetModelMaterial eID, mat BDpeAF8z Print "Set lens index of refraction = " & nlens V1M oW;& |dK_^~;o '************************************************************************* '6WaG
hvO 'Pupil diameter n>{>3? '************************************************************************* SBs_rhe eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *:wu{3g}M` w[t!?(![> 'Adjust pupil diameter (trimming volume inner hole) p "u5wJ_ A~u-Iv(U SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" .xS}/^8iD K[O'@v ' Adjust pupil location to just in front of the lens vk&C'&uV9@ parID = FindFullName( "Geometry.Arizona Eye" ) b k 30d eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) k1W
q$KCwG count = 0 <rNCb; While GetOperationCount(eID)>count 1 %K^(J; GetOperation eID, count, op [;%qxAB/_ If op.Type="ShiftZ" Then #)z_TM07P DeleteOperation eID,count "*a^_tsT?i count=count-1 <GT&q <4w End If SnRk` 5t count=count+1 j'g':U Wend N^H~VG&D( op.Type = "ShiftZ" 4fgA3% op.val1 = taq-0.01 BNL Q] op.parent = parID a!vF;J-Zqa AddOperation eID, op q3n(Z "CX&2Xfe Print "Set pupil diameter = " & pupilDiam >8\EdN59{ Q0s!]Dk 'Update AZ Eye subassembly Description |p}qK
Fdi eID = FindFullName( "Geometry.Arizona Eye" ) 0x*L"HD GetEntity eID, entity 0P_qtS entity.Description = "Accommodation = " & A & "D" 3!ZndWSHV SetEntity eID, entity l@Uo4b^4x \L Gj]mb1 Update :_X9x{ Print "DONE!" M:YtW5{ BxVo>r End Sub ju~js wGr5V! 如果屈光度是4,光瞳直径是4,则会输出如下数据: T*e>_\Tx 2|8e7q: +* Accommodation = 4 Diopters n$&xVaF| Pupil Diameter = 4 mm [oqb@J2 Set aqueous humor thickness = 2.81 ~H`~&? Set anterior lens radius = 10.4 and conic constant = -2.375869 )%FRBO] Set posterior lens radius = -4.424557 and conic constant = -3.081019 6qp2C]9= Set lens thickness = 3.927 dz3chy,3 Set lens index of refraction = 1.42672 os9X)G Set pupil diameter = 4 9M8n DONE! J0K25w
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