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简介 #$dk :VB{@ED 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 5|pPzEA> 4uSC> 模型 REaU=-m- ^Hplrwj} 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 /Ayo78Pi 4|EV`t}EV Table 1. AZ眼睛模型的定义 n$})}kj 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. $QbaPmHW .]IidsgM 光源 cc
%m0p ahnQq9 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 gTby%6-\| ov@N13 ,$ ar#Xe;T! 图1. 光源和提示信息使用 Alh"ZT^* 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。 3EHn}#+U F79!B 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。 }r)T75_1 4,yS7l 图2. 字母F光源的设定方法光 Te :4z@? GCEcg&s=\S 图3. 字母F在视网膜上位置点列图 #K[UqJ+x 视网膜的散射 vp#A D9h1 (oKrIm 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。
FK2* O |hlc#t? yN4K^# 图4. 视网膜朗伯散射设定 7H~J?_ 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。
Q9!T@ 9|}u"jJB%E FU~xKNr 图5. 视网膜重点采样规格设定 $^ wqoW%t 脚本 HF\|mL M
yvyp 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: @S%ogZz*m !MNnau%O 图6. 用户对话框的创建与编辑 0j--X?- 图7. 用户对话框编辑器 tt=JvI9> 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 NukcBH 余下的脚本计算与屈光度有关的所有参数。 (#t"u`_Ee <x^Ab#K" 分析 -%5O:n Q=+*OQV29 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 +5>*$L%8T` *G6Py,- !f 图7. 字母F在视网膜上颜色分析 t\/i9CBn 脚本代码 ^Qx
qv @5im*ubzM Option Explicit 'Remove this to enable non-dimensioned variables to be used. DF>LN%a~ )rqb<O Dim entity As T_ENTITY ,y'E#_cTgQ Dim op As T_OPERATION
,'KS:`m! Dim mat As T_MODELMATERIAL 5Wyo!pRi Dim A As Double >Fzs%]M Dim pupilDiam As Double Uzx,aYo X Dim eID As Long m4=[e! Dim parID As Long Tf|?j=f Dim count As Integer &Ti:IC%M Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double WFYbmfmV Dim tlens As Double, nlens As Double lhN2xg5x Dim curv As Double, conic As Double ^E)*i#."4 Dim ok As Long \9Z1'W V5ySOgzw, Sub Main 19r4J(pV
5\?\|* WT '用户输入对话框 u@ "nVHgMJ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ;g:!WXd TextBox 220,21,40,21,.TextBox1 'default: 0 2!7)7wlj0 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 \Y4>_Mk OKButton 40,91,90,21 3\ !DsPgW CancelButton 190,91,90,21 n[mVwQ(% Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 `[&) X TextBox 220,49,40,21,.TextBox2 'default: 4 ]WO0v`xh End Dialog }u>F}mUa Dim dlg As UserDialog P Tc@MH) nz?jNdyz ok = Dialog (dlg) YM:;mX5B gq'}LcV If ok=0 Then 'cancel button was pressed *i=+["A Print "Execution cancelled." U)PNY End p H5iv>H End If c6;326aDq ?bq S{KF 'Assign accommodation and pupil diameter & use defaults if field left empty &{x%"Aq/ If dlg.TextBox1 = "" Then m,u5S=3A{! A = 0 'Default accommodation 5Dhpcgq<< Else /F(wb_! A = CDbl(dlg.TextBox1) #TXN\YNP End If (F<VcB #JOWiO0> If dlg.TextBox2 = "" Then sp2"c"_+ pupilDiam = 4 'Default pupil diameter :nt 7jm, Else _>6xUt pupilDiam = CDbl(dlg.TextBox2) \L-K}U>J End If @AvDV$F tm"9` Print " " B;3lF;3` Print "Accommodation = " & A & " Diopters" cIm_~HH Print "Pupil Diameter = " & pupilDiam & " mm" TSl:a & -$@$ ' Calculate new parameters with accommodation 4)cQU.(*k taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness NB["U"1[^E yX {CV7%O Rant = 12.0 - 0.4*A 'Radius of anterior lens WRq:xDRn0 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens uA'S8b%C ,vxxp]#5 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens t,YnweH CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens HB>&}z0 X
J+y5at tlens = 3.767 + 0.04*A 'Lens thickness /|kR=
~ :|Ckr-k"1e nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction {c7ZA%T~R dTE(+M-
Gr 'Adjust parameters to account for accommodation @y|ZXPC# ]\qbe
'************************************************************************* g}cb>'=={ 'Aqueous thickness (Position of Lens) JTw< 4] '************************************************************************* !mM`+XH eID = FindFullName( "Geometry.Arizona Eye.Lens" ) jo7`DDb GetCustomElement eID, entity @1`!}.Tk 0TD cQ parID = FindFullName( "Geometry.Arizona Eye" ) a5)<roWQ B8f BX!u/ ' Delete any shift(s) in z 5-=&4R\k count = 0 s_/a1o While GetOperationCount(eID)>count I3ZlKI GetOperation eID, count, op r
I-A)b4 If op.Type="ShiftZ" Then V!|:rwG2 DeleteOperation eID,count /K@_O\+;Q count=count-1 h^H~q<R[T End If Ojh\H count=count+1 EJ%Kr$51K Wend y7x&/2 ;Sc}e/WJj 'Set new shift in Z4"SKsJT/> op.Type = "ShiftZ" 1TOT}h5 op.val1 = taq $jc&Tk# op.parent = parID <hJ%]] AddOperation eID, op O/?Lk*r Print "Set aqueous humor thickness = " & taq-0.55 ^57G]$Q ^|P/D '*************************************************************************
MeP,8,n' 'Radius and conic constant of anterior lens + YjK# '************************************************************************* $=IJ-_'o eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) KKCzq
| GetConic eID, entity, curv, conic z-J?x-< <$V!y
dO SetConic eID, entity, 1/Rant, CCant pPa3byWf Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant cnm*&1EzV mmJ$+$JEk '************************************************************************* 1-h"1UN2E 'Radius and conic constant of posterior lens ,>AA2@6zMT '************************************************************************* d'x'hp% eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) %6%QE'D GetConic eID, entity, curv, conic dYEsSFB m /^2&@P7 SetConic eID, entity, 1/Rpost, CCpost vmY 88Kx&S Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost MYmH?A )Rlh[Y& r '************************************************************************* , sOdc!![ 'Lens thickness (Position of posterior lens surface) Im<i.a
<` '************************************************************************* kT=KxS{ #77p>zhY parID = FindFullName( "Geometry.Arizona Eye.Lens" ) :/.SrkN(A7 qgk-[zW# ' Delete any z-shift(s) k;fy8 count = 0 )R- e^Cb While GetOperationCount(eID)>count {SQ#n@Q&$ GetOperation eID, count, op Yp;6.\Z8[ If op.Type="ShiftZ" Then S,* DeleteOperation eID,count H2cY}, count=count-1 ;7HL/- End If
W`d\A3v count=count+1 4D4Y.g_x Wend i'\7P-a .*x |TPv{ 'Set new z-shift pSPVY2qKX op.Type = "ShiftZ" N!TC}#}l op.val1 = tlens Mq#sSBE<K op.parent = parID b}C6/zW AddOperation eID, op ^&Re-{ES] Print "Set lens thickness = " & tlens 5LF#w_x \nKpJ9! '************************************************************************* hE9UWa.Q> 'Lens index of refraction JtB]EvpL} '************************************************************************* `
&E- eID = FindMaterial( "Lens" ) 8Q*477=I GetModelMaterial eID, mat $ lC*q Jq1^}1P mat.Nd = nlens :mI[fQ SetModelMaterial eID, mat Xh[02iL- Print "Set lens index of refraction = " & nlens HXg#iP^tv "lT>V)NB' '************************************************************************* xV}ybRKV 'Pupil diameter =_@Q+N*]|( '************************************************************************* 6%^9`|3 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) h%0FKi^ #A@d;U% 'Adjust pupil diameter (trimming volume inner hole) RoY"Haa op|:XLR5 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" #6'+e35^ 8 ?%]?#4bkc ' Adjust pupil location to just in front of the lens p?#%G`dm parID = FindFullName( "Geometry.Arizona Eye" ) P*kKeMl eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) _l$1@ count = 0 -IP 3I While GetOperationCount(eID)>count /BaXWrd+ GetOperation eID, count, op x392uS$# If op.Type="ShiftZ" Then 7XDze(O5 DeleteOperation eID,count Y;B#_}yF count=count-1 \U\k$ ( End If q]}1/JZS count=count+1 Qt
VZ)777 Wend W4ygJL7 6 op.Type = "ShiftZ" ;'fn{j6C op.val1 = taq-0.01 % njcWVP; op.parent = parID F VVpyB| AddOperation eID, op '-?t^@ ]ICBNJ Print "Set pupil diameter = " & pupilDiam Kd%>:E* &58TX[# 'Update AZ Eye subassembly Description =I6u*$9< eID = FindFullName( "Geometry.Arizona Eye" ) sP`
k{xG GetEntity eID, entity J nzI-
y entity.Description = "Accommodation = " & A & "D" jaOt"iU.B SetEntity eID, entity :{tj5P!S
"?Mf%u1R Update $At,D.mGkb Print "DONE!" B;6N.X(K (+=TKI<= End Sub f[;l7 ud@7%% 如果屈光度是4,光瞳直径是4,则会输出如下数据: v."0igMO Z7@~#)3 Accommodation = 4 Diopters h=`1sfz Pupil Diameter = 4 mm {W5D) Set aqueous humor thickness = 2.81 <Ky6|&! Set anterior lens radius = 10.4 and conic constant = -2.375869 OM4q/!)A] Set posterior lens radius = -4.424557 and conic constant = -3.081019 CNRiK;nQ Set lens thickness = 3.927 xSal=a;k Set lens index of refraction = 1.42672 V1= (^{p8 Set pupil diameter = 4 <e%~K4KH DONE! F87aIJ.pGN YJ[Jo3M@j0 =nTNL .SX QQ:2987619807 $>M A
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