Arizona眼睛模型
简介 2)X4y"l
YZc>dE 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。 0'5/K , %" D%: 模型 5U`ZbG =,y |00l 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。 =( v^5 i;/xK=L
Table 1. AZ眼睛模型的定义 d}'U?6ob 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. +Y"r71|A6+ Fd]\txOXj 光源 *NFg;<:j 'e)^m}:?D 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。 rxnFrx Ub1hHA*) VKp*9%9
图1. 光源和提示信息使用 54lu2gD' 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。 {n#k,b&9B ^I8Esl8 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。 fyTAou6hI e^p
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图2. 字母F光源的设定方法光 dZ#&YG)?e ?eH&'m}-
图3. 字母F在视网膜上位置点列图 F{06 _T 视网膜的散射 ">f erhN9 z]B]QB
Y[ 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。 Od+6 -J :x.7vZzxs z>sbr<doa
图4. 视网膜朗伯散射设定 %^sTU4D5 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。 '* mH*?Y !+>v[(OzM F+R?a+e
图5. 视网膜重点采样规格设定 pl@O
N"=[ 脚本 4[Z\
?[ FZjHw_pP 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: W} WI; cI {3;AwhN0H
图6. 用户对话框的创建与编辑 `&\Q +W
图7. 用户对话框编辑器 r/pH_@ 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。 L,y6^J! 余下的脚本计算与屈光度有关的所有参数。 sn7AR88M; QaUm1i# 分析 rpeJkG@+ CYOI.#m2 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 >U F U*90m~)
图7. 字母F在视网膜上颜色分析 ]7-&V-Ct* 脚本代码 u]}s)SmDk oFOnjK"|F Option Explicit 'Remove this to enable non-dimensioned variables to be used. +"9hWb5 n]8<DX99Q0 Dim entity As T_ENTITY z/i+EE Dim op As T_OPERATION dJ$"l|$$ Dim mat As T_MODELMATERIAL )`^p%k Dim A As Double [MuEoWrq(} Dim pupilDiam As Double f0Bto/,>~ Dim eID As Long &zs'/xv] Dim parID As Long vJAZ%aW Dim count As Integer 3u%{dG a Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double P[s8JDqu Dim tlens As Double, nlens As Double o7IxJCL=Q Dim curv As Double, conic As Double ss;R8:5 Dim ok As Long KWLbD# j
";2o( Sub Main [O:
!(Gje l5L.5$N '用户输入对话框 !i=nSqW Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 9 \^|6k, TextBox 220,21,40,21,.TextBox1 'default: 0 xf|mlHS+ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 [+qCs7' OKButton 40,91,90,21 k,euhA/& CancelButton 190,91,90,21 qI^
/"k*5 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 sz9L8f2 TextBox 220,49,40,21,.TextBox2 'default: 4 ^eW}XRI End Dialog }9nDo*A"} Dim dlg As UserDialog re> rr4@ &89oO@5 ok = Dialog (dlg) 1S@vGq} {Zp\^/ If ok=0 Then 'cancel button was pressed )BRKZQN Print "Execution cancelled." ve&zcSeb End N!*_La=TuH End If b!M"VDjQ LM2TZ 'Assign accommodation and pupil diameter & use defaults if field left empty @LJpdvb If dlg.TextBox1 = "" Then ?yh}/T\qp A = 0 'Default accommodation vTv]U5%:>% Else aL\nT XakX A = CDbl(dlg.TextBox1) 0OGCilOb* End If HF3f)}l$ #A]-ax?Qc} If dlg.TextBox2 = "" Then fxgr`nC pupilDiam = 4 'Default pupil diameter
&y<ZE Else
zxp` pupilDiam = CDbl(dlg.TextBox2) *OQG4aWy End If LzYO$Ir:g ak:c rrkx Print " " TRsE % Print "Accommodation = " & A & " Diopters" NH3cq Print "Pupil Diameter = " & pupilDiam & " mm" &N3Y|2 D-,L&R!` ' Calculate new parameters with accommodation [e1S^pI taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness g[w,!F 6 PxW8pn Rant = 12.0 - 0.4*A 'Radius of anterior lens 1h.)#g?{ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens SXt{k<| Z{H5oUk Rpost = -5.224557 + 0.2*A 'Radius of posterior lens n`4K4y%Dy} CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens j)
,,"54* F]9nB3:W tlens = 3.767 + 0.04*A 'Lens thickness Oh4AsOj@ $ Y 7c nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction c2K:FdB 'g9"Qv?0{` 'Adjust parameters to account for accommodation S(7ro]U9 z)uuxNv[R '************************************************************************* !Kv@\4 'Aqueous thickness (Position of Lens) BATG FS& '************************************************************************* \%p34K\ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 'TAUE{{ GetCustomElement eID, entity ?-Vjha@BO "]-Xmdk09 parID = FindFullName( "Geometry.Arizona Eye" ) b=/curl& gkHNRAL ' Delete any shift(s) in z h`3eu;5) count = 0 mg,j:, While GetOperationCount(eID)>count c5mZG7- GetOperation eID, count, op \o';"Q1H If op.Type="ShiftZ" Then 5y?-fT]X DeleteOperation eID,count +CI1V>6^ count=count-1 LzCw+@-umw End If Q~Z=(rP20 count=count+1 O2"gj"D Wend ~/_SMPLo M2U&?V C! 'Set new shift in @9&P~mo/ op.Type = "ShiftZ" 3
zn W= op.val1 = taq L;od6<.*m op.parent = parID PdVfO8- AddOperation eID, op t>H`X~SR? Print "Set aqueous humor thickness = " & taq-0.55 07hF2[i yZ!T8"mz{ '************************************************************************* _.-;5M- 'Radius and conic constant of anterior lens n!qV> k9Y '************************************************************************* j;Z?WXWDh eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) : g.46dp4 GetConic eID, entity, curv, conic $k$4%
7 _FwK-?4E- SetConic eID, entity, 1/Rant, CCant "al`$ %( Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant D0N9Ksq lq"f[-8a2q '************************************************************************* r `eU~7 'Radius and conic constant of posterior lens pNRk.m] '************************************************************************* d,by/.2 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) n k2om$nN GetConic eID, entity, curv, conic p7H3J?`w1+ CpQN,-4 SetConic eID, entity, 1/Rpost, CCpost <?D\+khlq Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost [ib P%xb MJ=)v]a '************************************************************************* tBct 'Lens thickness (Position of posterior lens surface) eW>3XD4 '************************************************************************* d9n?v)<v 'L{8@gqi parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Vn~UB#]'3 v)_nWu ' Delete any z-shift(s) lHV[Ln`\x count = 0 ,y%3mR_~ While GetOperationCount(eID)>count sFBneBub GetOperation eID, count, op dZ _zg< If op.Type="ShiftZ" Then =LTmr1? DeleteOperation eID,count !@'%G6:. count=count-1 FaBqj1O1 End If W14Vm(`N count=count+1 wd/<
8>2X Wend eX_D/25 $ b}Zd)2G 'Set new z-shift %_Yx<wR% op.Type = "ShiftZ" rS1fK1dys op.val1 = tlens ]!IVz)<E& op.parent = parID ?3O9eZY@ AddOperation eID, op I7&_Xr Print "Set lens thickness = " & tlens N 75:5 mR;qMX)0h '************************************************************************* zB?
V_aT 'Lens index of refraction sN("+ sZ.n '************************************************************************* ^_ojR4 eID = FindMaterial( "Lens" ) )(7&X45,k GetModelMaterial eID, mat \a+(=s(; a
{ab*tM mat.Nd = nlens .Q)|vq^ SetModelMaterial eID, mat fBQ?|~:n Print "Set lens index of refraction = " & nlens S1U@UC x2QIPUlf '************************************************************************* cJgBI(S5 'Pupil diameter V)P&Zw '************************************************************************* /CTc7.OYt eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) (5Sivw*mP }$\M{#C~ 'Adjust pupil diameter (trimming volume inner hole) vS;1/->WD r&Ca"dI SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" hva2o` S!{t6'8K ' Adjust pupil location to just in front of the lens bZx!0>h parID = FindFullName( "Geometry.Arizona Eye" ) X{kpSA~ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) )NR Q2 count = 0 P00f6 While GetOperationCount(eID)>count 6:%
L![FX GetOperation eID, count, op A6oq.I0 If op.Type="ShiftZ" Then =H<0o?8?c DeleteOperation eID,count "KJ%|pg_C count=count-1 }Yv\0\~'W| End If VxFOYC>p count=count+1 VB<Jf'NU Wend "G:<7oTa op.Type = "ShiftZ" V]S1X^ op.val1 = taq-0.01 ?RzD Qy D op.parent = parID !K?qgM AddOperation eID, op Tg3!R q55 U}$DhA"r" Print "Set pupil diameter = " & pupilDiam *6BThvg|&X 1oKfy>i e 'Update AZ Eye subassembly Description irk*~k ? eID = FindFullName( "Geometry.Arizona Eye" ) e5Mln!.o GetEntity eID, entity t\v+ogbk) entity.Description = "Accommodation = " & A & "D" j6(?D*x SetEntity eID, entity ~ 7)A"t
Yav2q3 Update d1joVUYE Print "DONE!" vKoP|z=m =e?$ M End Sub !jqWwi 6x=YQwn~ 如果屈光度是4,光瞳直径是4,则会输出如下数据: iqW1#)3'R , %YBG1E[y Accommodation = 4 Diopters vVT?h Pupil Diameter = 4 mm @d"wAZzD? Set aqueous humor thickness = 2.81 htP|3 B Set anterior lens radius = 10.4 and conic constant = -2.375869 h8jD}9^ Set posterior lens radius = -4.424557 and conic constant = -3.081019 *V(Fn-6( Set lens thickness = 3.927 (Vg}Hh?p Set lens index of refraction = 1.42672 (c v!Y=] Set pupil diameter = 4 6D;^uM2N DONE! X5
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