Arizona眼睛模型
简介 c#L.I k:yrh:JhB 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。 %;ZDw@_< CubBD+hl* 模型 X-']D_f|, 4|INy=<"t 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。 _|C T|q dXMO{*MF{H
Table 1. AZ眼睛模型的定义 yyv<MSU8 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. 1\LK[tvh 1
F+$\fLr 光源 X B[C&3I 3FQXp 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 `]$H\gNI[8 Pm=i(TBS/ _h1:{hF
图1. 光源和提示信息使用 [E:-$R 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 Sd?+j;/" 5X}OUn8 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 Wg[ThaZ Bc1MKE5
图2. 字母F光源的设定方法光 V5up/ 6b,1 MngfXm
图3. 字母F在视网膜上位置点列图 PESJ7/^E 视网膜的散射 e)Pm{:E F m$;p6&j 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。 $[HpY)MSRw 2`cVi"U Y6ORI
图4. 视网膜朗伯散射设定 z\6/?5D#v 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 |7:{vA5 gH[lpRu|7 B[{Ie
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图5. 视网膜重点采样规格设定 W<OO:B.ty 脚本 c
6$n: tRzo}_+N 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: 5imqZw a4D4*=!G0
图6. 用户对话框的创建与编辑 V~ [I /Vi
图7. 用户对话框编辑器 E?^A+)<" 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。 =:pN82.G 余下的脚本计算与屈光度有关的所有参数。 I.L8A|nZ m9li% p 分析 ("rIz8b 1`I#4f 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 >a5avSn +{/*P5
图7. 字母F在视网膜上颜色分析 VkDFR
[k_ 脚本代码 hP]zC1s @V5'+^O Option Explicit 'Remove this to enable non-dimensioned variables to be used. V[BlT|t }hX"A!0 Dim entity As T_ENTITY 9KLhAYaq Dim op As T_OPERATION +H8;*uZ|k, Dim mat As T_MODELMATERIAL `Ef&h V Dim A As Double Gj(UA1~1 Dim pupilDiam As Double D[iIj_CKQ Dim eID As Long js8GK Dim parID As Long C%+>uzVIw Dim count As Integer wJF Fg : Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double S&m5]h!D Dim tlens As Double, nlens As Double /DQcM.3
Dim curv As Double, conic As Double uyDYS Dim ok As Long QWWoj[d# SsF
5+=A Sub Main V7
dAB,: DUK.-|a7 '用户输入对话框 BA+:}81&<q Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 3kBpH7h4 TextBox 220,21,40,21,.TextBox1 'default: 0 rO`nS<G Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 v^_<K4N` OKButton 40,91,90,21 *>XY' -;2e CancelButton 190,91,90,21 3tTz$$-# Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 5"JnJH TextBox 220,49,40,21,.TextBox2 'default: 4 yYvv;E End Dialog ,.+"10=N. Dim dlg As UserDialog wOp# mT Y)L\*+
>"[ ok = Dialog (dlg) o )
FjWf; T6ZJ SKM If ok=0 Then 'cancel button was pressed lC|{{?m Print "Execution cancelled." "@[xo7T End CQcb !T End If <#9zc'ED: r6-'p0| 'Assign accommodation and pupil diameter & use defaults if field left empty S-:7P.#Q If dlg.TextBox1 = "" Then 9/k?Lv A = 0 'Default accommodation !u#o"e<qh Else s=nE'/q1| A = CDbl(dlg.TextBox1) q61
rNOw_ End If Pk; 9\0k7 " lf_`4 If dlg.TextBox2 = "" Then {&c%VVZb:Z pupilDiam = 4 'Default pupil diameter s
`r tr Else nA]dQ+5sT pupilDiam = CDbl(dlg.TextBox2) Ye}y_W End If EN%Xs578 []Z| *+=Q Print " " e-os0F Print "Accommodation = " & A & " Diopters" 6zLz<p? Print "Pupil Diameter = " & pupilDiam & " mm" XfxNyZsy&> wz!]]EQ!o ' Calculate new parameters with accommodation I$`Vw > taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness o+O\VNW 2/BFlb Rant = 12.0 - 0.4*A 'Radius of anterior lens ZX.VzZS CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ':!;6v|L 9_ Qm_ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ):+H`Hcm CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens g-% uw[pf 7q|(ZZa tlens = 3.767 + 0.04*A 'Lens thickness 5hp b=2 T[XI nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction &K^h'>t' I01On>"@7 'Adjust parameters to account for accommodation N_VAdNJ^: {F
k]X#j '************************************************************************* |U^
ff^] 'Aqueous thickness (Position of Lens) ){>;eky '************************************************************************* `>8| eID = FindFullName( "Geometry.Arizona Eye.Lens" ) :7Vm]xd}do GetCustomElement eID, entity Q$,8yTM [-$&pB>w8' parID = FindFullName( "Geometry.Arizona Eye" ) l:HO|Mq xm YA/wt8 ' Delete any shift(s) in z {djOU
9] count = 0 %e%nsj6 While GetOperationCount(eID)>count XpH[SRUx GetOperation eID, count, op i%*x7zjY{ If op.Type="ShiftZ" Then ~.x!st} DeleteOperation eID,count mk4%]t" count=count-1 l}(~q!r End If 4g1u9Sc0 count=count+1 JpDYB Wend Y+?bo9CES! DO03vN 'Set new shift in Ky nZzR op.Type = "ShiftZ" Y\p
yl op.val1 = taq ydns_Z op.parent = parID ,(`@ZFp$ AddOperation eID, op xJ&StN/' Print "Set aqueous humor thickness = " & taq-0.55 jSYj+k 1| gP
:t} '************************************************************************* ;v0sM*x%V 'Radius and conic constant of anterior lens e('c9 Y '************************************************************************* aYj3a;EmU eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ZTmdS GetConic eID, entity, curv, conic RPiCXpJv& iD(K*[;lc SetConic eID, entity, 1/Rant, CCant n1ED _9 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 2s{yg%U( @6D<D6` '************************************************************************* N{9<Tf * 'Radius and conic constant of posterior lens J)fS2Ni+ '************************************************************************* _ _)Z Q eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ;C"J5RA GetConic eID, entity, curv, conic Oy|9po tcX7Ua(I` SetConic eID, entity, 1/Rpost, CCpost ixS78KIr Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost vl*RRoJ W;-Qze\D '************************************************************************* T]vD ,I+ 'Lens thickness (Position of posterior lens surface) P!O#"(r2] '************************************************************************* lpp'.HTP 2d>PN^x parID = FindFullName( "Geometry.Arizona Eye.Lens" ) *TXq/
3g XW#4C*5?d ' Delete any z-shift(s) %eah=e count = 0 8%|x) While GetOperationCount(eID)>count FFQF0.@EBi GetOperation eID, count, op NFSPw`f If op.Type="ShiftZ" Then TRq~n7Y7C DeleteOperation eID,count 8p211MQ< count=count-1 FCe503qND$ End If SUVr&S6Nk count=count+1 pj )I4C) Wend u3ZG;ykM n)=&=Uj`f 'Set new z-shift PLY7qMw op.Type = "ShiftZ" JIQzP?+? op.val1 = tlens A|&EI-In op.parent = parID /.?\P#9) AddOperation eID, op <^~F~]wnH Print "Set lens thickness = " & tlens X%-4x M)xK+f2_[ '************************************************************************* qQ_B[?+W 'Lens index of refraction v8 X&H '************************************************************************* *=
71/&B eID = FindMaterial( "Lens" ) ]d[q:N]z GetModelMaterial eID, mat vP?yl "U bCrB'&^t mat.Nd = nlens Ya. $x~ SetModelMaterial eID, mat Kq?7#,_ Print "Set lens index of refraction = " & nlens .Sn1YAhE B';Ob '************************************************************************* )6j:Mbz 'Pupil diameter 3edAI&a5 '************************************************************************* 4Klfnki eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) X"0Q) {k*_'0 'Adjust pupil diameter (trimming volume inner hole)
4[ra QE gv,J{ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 8tL61x{] .3&m:P8zV ' Adjust pupil location to just in front of the lens FX^E | parID = FindFullName( "Geometry.Arizona Eye" ) bDo'hDmW eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Q.\>+4]1&& count = 0 P2p^jm
While GetOperationCount(eID)>count }';&0p2Z GetOperation eID, count, op \f
LBw0 If op.Type="ShiftZ" Then la4,Z DeleteOperation eID,count U)!AH^{32 count=count-1 Y'5ck( End If P Cf|^X#B count=count+1 hF~B&^dd. Wend =<05PB op.Type = "ShiftZ" ,fw[ J op.val1 = taq-0.01 jveRiW@ op.parent = parID Kv]6 b2HT AddOperation eID, op a)1,/:7' ie!4z34 Print "Set pupil diameter = " & pupilDiam "!tB";n b{rmxtx 'Update AZ Eye subassembly Description _D9=-^ eID = FindFullName( "Geometry.Arizona Eye" ) M9K).P= GetEntity eID, entity DX";v
J entity.Description = "Accommodation = " & A & "D" IT(c'} SetEntity eID, entity /v{[Z&z Z@ kC28 Update |DW'RopM Print "DONE!" o,yvi VO Qt{v{1| End Sub &EPEpN
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K=E]p 如果屈光度是4,光瞳直径是4,则会输出如下数据: h+UscdUl :RsPGj6 Accommodation = 4 Diopters fF("c6:w( Pupil Diameter = 4 mm }dUC^04 Set aqueous humor thickness = 2.81 Z?.*.<"Sj Set anterior lens radius = 10.4 and conic constant = -2.375869 =T)2wcXBB Set posterior lens radius = -4.424557 and conic constant = -3.081019
x]oQl^F Set lens thickness = 3.927 E/ZJ\@gzD Set lens index of refraction = 1.42672 *u/|NU&X Set pupil diameter = 4 Lf#G?]@ DONE! -y?Z}5-rs
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