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2016-02-24 12:53 |
FRED运用:Arizona眼睛模型
简介 S<^*jheO5 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。 KobNi#O+ uS :3Yo 模型 ahgm*Cpc }>:v 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。 zo66=vE! +gb2>fei&
Table 1. AZ眼睛模型的定义 [attachment=67931]
/|] %0B 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. :32 S!gV\gEbDj 光源 e*gCc7zz e9r#r~Qq| 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。 _%Q\G,a; rtcY(5Q 2%g)0[1
[attachment=67932] 图1. 光源和提示信息使用 ?! dp0< 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。 )mO|1IDTN Ikiv+Fq( 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。 hNXP-s r.M8#YL
[attachment=67933] 图2. 字母F光源的设定方法光 T1m097 `T $lTP
[attachment=67934] 图3. 字母F在视网膜上位置点列图 *,1^{mb 视网膜的散射 rlu{C4l NC::;e 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 Tysh~C|1 r-]Au - KfJF9!U*?
[attachment=67935] 图4. 视网膜朗伯散射设定 \XwXs5"G 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 *ie#9jA G`E%uyjG$j 3$+|nP:U
[attachment=67936] 图5. 视网膜重点采样规格设定 +GMM&6< 脚本 ,c_[`q\ DV +DJcF 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: l'-dB 6TS+z7S81L
[attachment=67937] 图6. 用户对话框的创建与编辑 o PRvd_~
[attachment=67938] 图7. 用户对话框编辑器 0}$",M!p 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。 WQ4:='( 余下的脚本计算与屈光度有关的所有参数。
04NI.Jv Fc>W]1 分析 y|V/xm+Fp %,%s09tO 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 g':mM*j& hX\XNiCiK8
[attachment=67939] 图7. 字母F在视网膜上颜色分析 msg&~"Z 脚本代码 q.i@Lvu# 7(na?Z$
Option Explicit 'Remove this to enable non-dimensioned variables to be used. cl{x5>.'# j['Z|Am"l Dim entity As T_ENTITY -?<wvUbR{ Dim op As T_OPERATION 2;.7c+r0 Dim mat As T_MODELMATERIAL 2Xk(3J!!'a Dim A As Double rFZB6A<(] Dim pupilDiam As Double oH!sJ&"#_ Dim eID As Long ]hTYh^'e Dim parID As Long $6atr-Pb Dim count As Integer 9ET2uDZpL Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double \^SL Zhe Dim tlens As Double, nlens As Double Y>Q9?>}Q Dim curv As Double, conic As Double Rj9ME,u Dim ok As Long punc'~
OM{-^ Sub Main GEfX,9LF & /lDW5;d '用户输入对话框 MGX %U6 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 N5csq( TextBox 220,21,40,21,.TextBox1 'default: 0 zAt!jP0E Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 cqr!* OKButton 40,91,90,21 vG#|CO9 CancelButton 190,91,90,21 ]"q[hF*PM Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 gt6*x=RCrQ TextBox 220,49,40,21,.TextBox2 'default: 4 :^lyVQ%@ End Dialog l*("[?>I Dim dlg As UserDialog U#1T
HO` ^"K ok = Dialog (dlg) qdm5dQ (c <M=U @ If ok=0 Then 'cancel button was pressed 3G8BYP Print "Execution cancelled." C*ZgjFvB End q%
)Y End If |gx{un` lYT}Nc4"=" 'Assign accommodation and pupil diameter & use defaults if field left empty vlIet$k If dlg.TextBox1 = "" Then 6#6Ve$Vl] A = 0 'Default accommodation )y'`C@ijI Else *aS|4M- A = CDbl(dlg.TextBox1) p=\DZU~1 End If I>bLgt]u3 |M`B If dlg.TextBox2 = "" Then $1.iMHb
pupilDiam = 4 'Default pupil diameter TbU\qcm]] Else REB8_ H" pupilDiam = CDbl(dlg.TextBox2) \`jFy[(Pa' End If lZV]Z3=p'0 6Z
~>d;&9 Print " " Y1+4ppZ Print "Accommodation = " & A & " Diopters" fo&q/;l\ Print "Pupil Diameter = " & pupilDiam & " mm" rw8O<No4.o t*zve,?} ' Calculate new parameters with accommodation cQzd0X taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness jpZX5_o aoz+g,1
// Rant = 12.0 - 0.4*A 'Radius of anterior lens HnUM:-6 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens kf_s.Dedw 5H:NY| Rpost = -5.224557 + 0.2*A 'Radius of posterior lens X<K[`
=I CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens +cheLc wd~e3%JM tlens = 3.767 + 0.04*A 'Lens thickness WW0N"m' ii2X7Q nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 1sYwFr 5 /#20`;~F) 'Adjust parameters to account for accommodation H.XD8qi3W %Ub"V\1 '************************************************************************* FT/H~|Z> 'Aqueous thickness (Position of Lens) g10$pf+L '************************************************************************* .hn{m9|U eID = FindFullName( "Geometry.Arizona Eye.Lens" ) b.47KJz t GetCustomElement eID, entity 8<0H(lj7_ /],:sS7 parID = FindFullName( "Geometry.Arizona Eye" ) `(H]aTLt , i|Lir{vW ' Delete any shift(s) in z eT[,k[#q count = 0 s!nFc{ While GetOperationCount(eID)>count # Fw<R'c GetOperation eID, count, op x%k4Lm If op.Type="ShiftZ" Then o B_c6]K DeleteOperation eID,count QB#f'X count=count-1 mV@.JFXKP End If 60[f- 0X count=count+1 hZY+dHa] Wend '|':W6m, (NOAHV0H 'Set new shift in r-^Ju6w{ op.Type = "ShiftZ" =+T{!+|6P op.val1 = taq YUfuS3sX} op.parent = parID S"CsY2; AddOperation eID, op 7SoxsT) Print "Set aqueous humor thickness = " & taq-0.55 }EE FgE6j; '************************************************************************* ,8;;#XR3 'Radius and conic constant of anterior lens !lm^(SSv '************************************************************************* g v&xC 6> eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) J^hj
R%H GetConic eID, entity, curv, conic 1& YcCN\k ;EW]R9HCH SetConic eID, entity, 1/Rant, CCant L;Nz\sJ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant , =IbZ <po.:c
Ce '************************************************************************* Pw1V1v&>q 'Radius and conic constant of posterior lens 92]>" '************************************************************************* bnWIB+%_ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) .r[DqC GetConic eID, entity, curv, conic P%xk
}=^YLu= SetConic eID, entity, 1/Rpost, CCpost MkC25 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 2fO ~%!.G L=Dd` '************************************************************************* E$ q/4 'Lens thickness (Position of posterior lens surface) '-D-H}%;}M '************************************************************************* |n=m8X 6f?5/hq parID = FindFullName( "Geometry.Arizona Eye.Lens" ) kR%CSLOVy &1F)/$,v ' Delete any z-shift(s) 09_3`K.* count = 0 |D$U{5}Mv While GetOperationCount(eID)>count 8n?P'iM GetOperation eID, count, op "@
Zy+zLU If op.Type="ShiftZ" Then d5T0#ue/e DeleteOperation eID,count _;yp^^S count=count-1 l|%7)2TyG) End If .P# c/SQp count=count+1 JZD27[b Wend $T^O3 8$ FxKH?Rl 'Set new z-shift "#rlL^9v op.Type = "ShiftZ"
1mJBxg}( op.val1 = tlens }{ pNasAU op.parent = parID Um9!<G=; AddOperation eID, op [m|\N Print "Set lens thickness = " & tlens hDl& K E @=K> uyB '************************************************************************* ]QtdT8~ 'Lens index of refraction ?fnJ`^|-r '************************************************************************* >
9JzYI^ eID = FindMaterial( "Lens" ) m589C+7 GetModelMaterial eID, mat ^ ^} hK@1
s mat.Nd = nlens c<A@Op"A SetModelMaterial eID, mat "h_n/}r= Print "Set lens index of refraction = " & nlens cI?dvfU? Q6MDhv, '************************************************************************* +C/K@:p 'Pupil diameter UQPd@IVu6 '************************************************************************* QP7EP aW eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) s)375jCga *.Y!ZaK 'Adjust pupil diameter (trimming volume inner hole) w<J$12
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&,vju SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" M7eO5 kzLj1Ix2 ' Adjust pupil location to just in front of the lens _Y|k \|' parID = FindFullName( "Geometry.Arizona Eye" ) X~ P0Q eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) A}~hc&J count = 0 Z A1?' While GetOperationCount(eID)>count G&/}P$ GetOperation eID, count, op m3F.-KPO If op.Type="ShiftZ" Then =XQ3sk6U DeleteOperation eID,count <Sm=,Sw count=count-1 3yr{B Xn End If L;,Nh count=count+1 V F6OC4 K Wend VXn]*Mo op.Type = "ShiftZ" H^K(1
op.val1 = taq-0.01 89`AF1 op.parent = parID 1^}()H62} AddOperation eID, op D4Uz@2_ 9 ?MOeOV8 Print "Set pupil diameter = " & pupilDiam wjq f u / OZ![9l 'Update AZ Eye subassembly Description e~'y %| D eID = FindFullName( "Geometry.Arizona Eye" ) ]=WJ%p1l GetEntity eID, entity A.
U< entity.Description = "Accommodation = " & A & "D" "LaNXZ9 SetEntity eID, entity y"cK@sOo ]AERi]
B Update g}ciG!0 Print "DONE!" tI*u"%#t o7/_a/ End Sub []3xb`<& ]8+%57:E 如果屈光度是4,光瞳直径是4,则会输出如下数据: u-OwL1S+ C0i: *1 Accommodation = 4 Diopters rU<
H7U Pupil Diameter = 4 mm %dw-}1X Set aqueous humor thickness = 2.81 |rW}s+Kcr Set anterior lens radius = 10.4 and conic constant = -2.375869 S,G=MI" Set posterior lens radius = -4.424557 and conic constant = -3.081019 U+@yx>! Set lens thickness = 3.927 Mr2dhSQ! Set lens index of refraction = 1.42672 r5lp<md Set pupil diameter = 4 F mh;d*IT DONE! |WXu;uf$.u H!Uy4L~>
(文章来源:讯技光电)
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