FRED运用:Arizona眼睛模型
简介 EawtT 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。 6V6,m4e 2kVQ#JyuRI 模型 bx=9XZ9g Nkg^;-CV0 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~g#Z +a!uS0fIJi
Table 1. AZ眼睛模型的定义 [attachment=67931] c$52b4=a 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. NncII5z o`}(1$a> 光源 #x[3@zP. O t1:z:Pl 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。 x|q|> dPB i+eDBg6 -Gmg&yQ9
[attachment=67932] 图1. 光源和提示信息使用 qASV\
<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。 GP;UuQz I18<brZJ 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。 Vf] ;hm XD$;K$_7
[attachment=67933] 图2. 字母F光源的设定方法光 2r>I,TNHl $V2.@X
[attachment=67934] 图3. 字母F在视网膜上位置点列图 i.G"21M 视网膜的散射 u$V8fus0 56T{ JTo 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。 "=vH,_"Ql Z}s56{!. dId&tTMmC
[attachment=67935] 图4. 视网膜朗伯散射设定 ]aTF0 R 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。 ;Br
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[attachment=67936] 图5. 视网膜重点采样规格设定 Xgyi}~AoaU 脚本 *zTEK:+_ z`KP
}- 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: 6P U]I+ APM!xX=N
[attachment=67937] 图6. 用户对话框的创建与编辑 @]xHt&j
[attachment=67938] 图7. 用户对话框编辑器 q_[V9 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。 S^*ME*DDz 余下的脚本计算与屈光度有关的所有参数。 [ %:%C]4 DZ5QC aA 分析 d<+@cf_9 `=JGlN7 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 (4oO8aBB lz88//@gZ
[attachment=67939] 图7. 字母F在视网膜上颜色分析 Ze- MB0w 脚本代码 K6M_b?XekA u[~= a5:4 Option Explicit 'Remove this to enable non-dimensioned variables to be used. GG$&=.$ d
gRTV<vM Dim entity As T_ENTITY =%ZR0cWPoI Dim op As T_OPERATION [[gfR'79{ Dim mat As T_MODELMATERIAL 5BsfbLKC Dim A As Double 85 <%L:EC Dim pupilDiam As Double unN=yeut Dim eID As Long +#MQ8d Dim parID As Long wS}Rl}#Oh? Dim count As Integer 6
~d\+aV Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double NQ qq\h Dim tlens As Double, nlens As Double tX7TP( Dim curv As Double, conic As Double i$W
E1- Dim ok As Long MR-cO Pn WuUT>omH Sub Main jhkNi`E7 PuoN<9 # '用户输入对话框 6 Z7J<0 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 vQhi2J' TextBox 220,21,40,21,.TextBox1 'default: 0 TB(!*t Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 \bzT=^Z;2 OKButton 40,91,90,21 `R{ ZED
l' CancelButton 190,91,90,21 SlojB ^% Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 w;(B4^? TextBox 220,49,40,21,.TextBox2 'default: 4 B#Z-kFn@ End Dialog 2z615?2_U Dim dlg As UserDialog ' &j]~m ![CF
>:e ok = Dialog (dlg) fS?fNtD6< :MbD=sX If ok=0 Then 'cancel button was pressed 'W]oQLD^R Print "Execution cancelled." AagWswv{Bf End [$P.ek< End If &7m)K>E27 @#W$7Gwf0 'Assign accommodation and pupil diameter & use defaults if field left empty TVEFZ\p<A If dlg.TextBox1 = "" Then H]d'#1G A = 0 'Default accommodation OJ2I (8P Else RRBBz7:~ A = CDbl(dlg.TextBox1) T_1p1Sg End If 4[^lE?+ ;)gNe:Q If dlg.TextBox2 = "" Then U**v'%{s pupilDiam = 4 'Default pupil diameter Z4aK Else 1l`$. k pupilDiam = CDbl(dlg.TextBox2) GYM6 ` End If j~:N8(= @!zT+W& Print " " %zA$+eT Print "Accommodation = " & A & " Diopters" $,L,VYN Print "Pupil Diameter = " & pupilDiam & " mm" At=l>
sg!*%*XQ ' Calculate new parameters with accommodation n`af2I2 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 8
y+N l&"V Vj{}cL"MR Rant = 12.0 - 0.4*A 'Radius of anterior lens 6q]`??g. CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens *N|s+ TSCc=c Rpost = -5.224557 + 0.2*A 'Radius of posterior lens }R]^%q @& CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens OP}8u"\Z BL Q&VI4 tlens = 3.767 + 0.04*A 'Lens thickness BpQ/$?5E" j*05!j<' nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ezR!ngt eg
vgi?y 'Adjust parameters to account for accommodation KB^i=+xr {f
}4l '************************************************************************* YDMimis\H5 'Aqueous thickness (Position of Lens) F6h|AF|" '************************************************************************* ' y9yx[P eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 61^5QHur GetCustomElement eID, entity zkrcsc\Z~0 :5M7*s)e16 parID = FindFullName( "Geometry.Arizona Eye" ) .0zNt ;
3WA-nn ' Delete any shift(s) in z kW=GFj)L count = 0 YN@4.&RP While GetOperationCount(eID)>count _^)<d$R< GetOperation eID, count, op ugI9rxT]Kv If op.Type="ShiftZ" Then m+m,0Ey5H DeleteOperation eID,count @^';[P! count=count-1 HRY?[+ End If 0u'qu2mV count=count+1 s
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Wend g,
%xGQ4+ VY9|8g/ 'Set new shift in pwvcH3l/r op.Type = "ShiftZ" &4ScwK: op.val1 = taq Wqu][Wa[Z op.parent = parID uM^eoh_ AddOperation eID, op k'K&GF1B Print "Set aqueous humor thickness = " & taq-0.55 M9/c8zZ %EooGHGF? '************************************************************************* {G
D<s)) 'Radius and conic constant of anterior lens 7.o:(P1??g '************************************************************************* V~uH)IMkh7 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) domaD"C GetConic eID, entity, curv, conic ( IXe555 SOI$Mx SetConic eID, entity, 1/Rant, CCant >7VOytc Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 2h6<'2'o1 :|:Disg '************************************************************************* '$3]U5KOwK 'Radius and conic constant of posterior lens 9N [PZD '************************************************************************* v){&g5djl eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 'xUyGj: GetConic eID, entity, curv, conic \p-3P)U lKMOsr@l SetConic eID, entity, 1/Rpost, CCpost WUM&Lq
k" Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost hwaU;> F RN1q/H| '************************************************************************* wW~y?A"{2 'Lens thickness (Position of posterior lens surface) )@xHL]!5m '************************************************************************* 3f2%+2Zjt, c7[<X<yk parID = FindFullName( "Geometry.Arizona Eye.Lens" ) R7o3X,-iwn W -Yv0n3 ' Delete any z-shift(s) (hB&OP5Fne count = 0 8X@p?43 While GetOperationCount(eID)>count |=^p`CT GetOperation eID, count, op 3TRzDE(J If op.Type="ShiftZ" Then v>FsP$p4yE DeleteOperation eID,count Zr0bVe+h count=count-1 RnN]m!"5 End If 3iHUG^sLW count=count+1 Tl^9!>\Q Wend ymdZ#I- SO#NWa<0| 'Set new z-shift !1tHg Z2\ op.Type = "ShiftZ" ieN}Ajl2 op.val1 = tlens 2nW:|*:/p6 op.parent = parID lLO|, AddOperation eID, op gBzg'Z Print "Set lens thickness = " & tlens j~(s3pSCo .5ap9li] '************************************************************************* P8N`t&r"7 'Lens index of refraction o5 UM)g '************************************************************************* 0j^QY6 eID = FindMaterial( "Lens" ) 8E:8iNbF GetModelMaterial eID, mat 7~@9=e8G }fps~R mat.Nd = nlens g\CRx^s SetModelMaterial eID, mat t6GL/M4 Print "Set lens index of refraction = " & nlens ~s@PP'! ^ lrq`1k '************************************************************************* *9#6N2J$M 'Pupil diameter mRe BS '************************************************************************* B{UL(6\B eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *=Ko"v
} v=kQ/h 'Adjust pupil diameter (trimming volume inner hole) _g|zDi^ &Kuo|=f SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" H ?Vo#/ D#ZzhHHP ' Adjust pupil location to just in front of the lens C&\MDOjx parID = FindFullName( "Geometry.Arizona Eye" ) ,(H`E?m1w4 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 8$k `bZ count = 0 B?BB While GetOperationCount(eID)>count `SdvXn GetOperation eID, count, op YP*EDb?f If op.Type="ShiftZ" Then xbbQ)sH&m DeleteOperation eID,count : +Na8\d count=count-1 L *a:j End If E8_j?X1 count=count+1 :fo.9J Wend X$aN:!1 op.Type = "ShiftZ" !S0$W?* op.val1 = taq-0.01 KIyhvY~ op.parent = parID @>>8CU^~ AddOperation eID, op b@GL*Z h(q,-')l_ Print "Set pupil diameter = " & pupilDiam eI?|Ps{S {+`'ZU6C 'Update AZ Eye subassembly Description F1m 1% eID = FindFullName( "Geometry.Arizona Eye" ) `/W6,] GetEntity eID, entity ,t"?~Hl". entity.Description = "Accommodation = " & A & "D" Lp!4X1/|\ SetEntity eID, entity )qDCh v5 |XyN" Update tM&O<6Y Print "DONE!" I4[sf 1r!o,0!d-' End Sub MIV<"A DGR[2C)@N 如果屈光度是4,光瞳直径是4,则会输出如下数据: YJBlF2uD U/hf?T; Accommodation = 4 Diopters Ll"
Kxg Pupil Diameter = 4 mm fN)A`> iP Set aqueous humor thickness = 2.81 pD^7ZE6 Set anterior lens radius = 10.4 and conic constant = -2.375869 Ue:LKK1Gsr Set posterior lens radius = -4.424557 and conic constant = -3.081019 MR= dQc Set lens thickness = 3.927 |6]2X W Set lens index of refraction = 1.42672 ;iol 2 Set pupil diameter = 4 JQi+y; DONE! $&fP%p |hx"yy'ux
(文章来源:讯技光电)
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