FRED运用:Arizona眼睛模型
简介 \[^!
ys 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。 :Q@/F;Z? N0vECk 模型 ,u)jZ7 $AE5n>ZD$ 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。 +8itP> DZ\K7-
Table 1. AZ眼睛模型的定义 [attachment=67931] /wt7KL-I 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. /S1/ ZI ^m&P0 光源 Vp|?R65S*
[)~1Lu 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。 K5BL4N Q9xb7)G _*Z3,*~"X
[attachment=67932] 图1. 光源和提示信息使用 TB+k[UxB 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。 `8RKpZv& 9:-7.^`P 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。 @|Yn~PwKs k{N!}%*2
[attachment=67933] 图2. 字母F光源的设定方法光 f% )9!qeW 0< vJ*z|_
[attachment=67934] 图3. 字母F在视网膜上位置点列图 y1Z>{SDiq 视网膜的散射 {+E]c:{ oZd 3H 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。 g,]m8%GHE PoPR34]^J vgD+Y
[attachment=67935] 图4. 视网膜朗伯散射设定 =|ODa/2p 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。 .SER,],P gD4vV'| cy;i1#1rO
[attachment=67936] 图5. 视网膜重点采样规格设定 (=Kv1
H aD 脚本 6kdbbGO- {tY1$}R 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: ~"SQwE| $8%"bR;Hu
[attachment=67937] 图6. 用户对话框的创建与编辑 n-l_PhPQ`
[attachment=67938] 图7. 用户对话框编辑器 s hH2/.> 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 #fns3=/H 余下的脚本计算与屈光度有关的所有参数。 tO:JB&vO2 y#iz$lX R 分析 % ym};7'&b "V26\ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 H)7v$A,5% /]!2k9u\
[attachment=67939] 图7. 字母F在视网膜上颜色分析 2tpu v(H; 脚本代码 L8Tm8) /r"<:+ Option Explicit 'Remove this to enable non-dimensioned variables to be used. .7gh2K ~o"=4q`> Dim entity As T_ENTITY :ZIa Dim op As T_OPERATION Ue
>]uZ| Dim mat As T_MODELMATERIAL @=dv[P"jn Dim A As Double p8%qU>~+4 Dim pupilDiam As Double Y'iyfnk Dim eID As Long 6{1=3.CL Dim parID As Long $KGMAg/H Dim count As Integer j_N<aX Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double I@/
G#3Zr Dim tlens As Double, nlens As Double C:5-h(# Dim curv As Double, conic As Double qfE0J;e Dim ok As Long iKJqMES /u4RZ|&as Sub Main 9AX}V6\+ ^?+[yvq '用户输入对话框 xS/W}-dPv Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Nyy&'\`! TextBox 220,21,40,21,.TextBox1 'default: 0 U,EoCAm> Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 S1U0sP@o OKButton 40,91,90,21 Nb&j?./ CancelButton 190,91,90,21 @`4T6eL5 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 S7f.^8 TextBox 220,49,40,21,.TextBox2 'default: 4 m.Zy$SDj( End Dialog _90D4kGU Dim dlg As UserDialog Y|fD)zG_ K!&W} _@l ok = Dialog (dlg) lTMY|{9 v-3VzAd=*& If ok=0 Then 'cancel button was pressed .s*N1
U?h Print "Execution cancelled." j}ob7O&U'w End WK`o3ayH- End If fe/;U=te KQNQ<OE4 'Assign accommodation and pupil diameter & use defaults if field left empty -!1=S: S If dlg.TextBox1 = "" Then )4=86>XJT A = 0 'Default accommodation d/Q#Z Else <}{<FXk[ A = CDbl(dlg.TextBox1) $kTm"I End If j*?8w(! T:@6(_Z If dlg.TextBox2 = "" Then nD
BWm`kN pupilDiam = 4 'Default pupil diameter //2O#Fg{/ Else cj>UxU][eS pupilDiam = CDbl(dlg.TextBox2) A,<5W } End If ,^?g\&f( ay7\Ae] Print " " FprdP*/ Print "Accommodation = " & A & " Diopters" $C7a#?YF, Print "Pupil Diameter = " & pupilDiam & " mm" ,6;n[p"h|r %@Gy<t, ' Calculate new parameters with accommodation _HHvL= taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 8)1q,[:M '/u|32 Rant = 12.0 - 0.4*A 'Radius of anterior lens AyO%,6p[ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens UF!qp ?0/$RpFEM# Rpost = -5.224557 + 0.2*A 'Radius of posterior lens +s}&'V^ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 940:NOgm uMw6b=/U tlens = 3.767 + 0.04*A 'Lens thickness P!+Gwm{ ;Yee0O!d4 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 7?whxi Qs (& SU)Uvu 'Adjust parameters to account for accommodation $^iio@SW{ W9%v#;2 '************************************************************************* ^\ x'4!W 'Aqueous thickness (Position of Lens) + kKanm[!v '************************************************************************* GfELL`yz eID = FindFullName( "Geometry.Arizona Eye.Lens" ) S<i1t[E@W GetCustomElement eID, entity uM`i!7} %JE>Z] parID = FindFullName( "Geometry.Arizona Eye" ) t<` As6} (SRY(q ' Delete any shift(s) in z .gg0rTf=- count = 0 C~pas~ While GetOperationCount(eID)>count !ddyJJ^a GetOperation eID, count, op $.Tn\4z& If op.Type="ShiftZ" Then O"'xAPQW DeleteOperation eID,count H\QkU`b count=count-1 &'>m;W End If @G2# Z count=count+1 xZ`z+) Wend 5bt>MoKxv YYn8!FIe 'Set new shift in z+yq%O op.Type = "ShiftZ" Qa_V op.val1 = taq _!o8s%9be op.parent = parID v]( Y n)# AddOperation eID, op vQ*[tp#qU Print "Set aqueous humor thickness = " & taq-0.55 u$R5Q{H_ )7*'r@ '************************************************************************* Dq<la+VlO 'Radius and conic constant of anterior lens ]Kq<U%x$ '************************************************************************* )=Z;H"_ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 7zH2dqrj GetConic eID, entity, curv, conic R)66qRf C^"zU>W_ SetConic eID, entity, 1/Rant, CCant $"vz>SuB Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 3l<qcKKc 3FR(gr$X '************************************************************************* c7r(&h 'Radius and conic constant of posterior lens jlP*RX '************************************************************************* T MMKRC1< eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) q2E{o)9 GetConic eID, entity, curv, conic 44*#qLN AT1cN1:4? SetConic eID, entity, 1/Rpost, CCpost ,RR{Y- Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost HZAT_ u*@R`,Y
'************************************************************************* h,Hr0^? 'Lens thickness (Position of posterior lens surface) QWOPCoUet '************************************************************************* H*N <7# "?zWCH parID = FindFullName( "Geometry.Arizona Eye.Lens" ) VF2,(f-* -]0:FKW ' Delete any z-shift(s) 67rY+u% count = 0 (O J/u)W^ While GetOperationCount(eID)>count nKGQU,C GetOperation eID, count, op m
.(ja If op.Type="ShiftZ" Then tAN!LI+w DeleteOperation eID,count eWDXV-xD count=count-1 anW['!T9{s End If J-<P~9m~I count=count+1 ?sQg{1"Zr Wend |/K|Vwa fsjLD|?|: 'Set new z-shift +1T>Ob;hk op.Type = "ShiftZ" )(G<(eiD op.val1 = tlens c)#7T<>*' op.parent = parID z~h?"' AddOperation eID, op #k9&OS? Print "Set lens thickness = " & tlens G06;x j:cu;6| '************************************************************************* >;Hx<FKxP 'Lens index of refraction T@ESMPeU:X '************************************************************************* YWn""8p;P eID = FindMaterial( "Lens" ) 9R$$(zB 1; GetModelMaterial eID, mat ~:JAWs$\V /rZk^/' mat.Nd = nlens '|]}f }Go SetModelMaterial eID, mat R8[VD iM6E Print "Set lens index of refraction = " & nlens nX:E(9q7c oA5Qk3b: '************************************************************************* T2rwK2 'Pupil diameter sd\}M{U '************************************************************************* d"n>Q Tn\ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) |5(un# _XZK2Q[ 'Adjust pupil diameter (trimming volume inner hole) E&J<qTH9 K7C
<}y SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" SHYekX g"sb0d9 ' Adjust pupil location to just in front of the lens Y&b Yaq parID = FindFullName( "Geometry.Arizona Eye" ) B)7 :*Kj eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 4e>f}u5 count = 0 4OM
]8I! While GetOperationCount(eID)>count (+v':KH3_ GetOperation eID, count, op :a Cf@:'] If op.Type="ShiftZ" Then e/Z{{FP%6 DeleteOperation eID,count iyCH)MA count=count-1 s@~3L End If "oxUKT count=count+1 1^o})9 Wend 4}D&=0IZ op.Type = "ShiftZ" Fb<'L5}i op.val1 = taq-0.01
z}J~X%}e op.parent = parID Mm8_EjMp AddOperation eID, op #(qvhoi7lM DOtz Print "Set pupil diameter = " & pupilDiam ;PMPXN'z6 o]p$
w[5 'Update AZ Eye subassembly Description *8qRdI9 eID = FindFullName( "Geometry.Arizona Eye" ) axnVAh|}S GetEntity eID, entity T#rUbi>"" entity.Description = "Accommodation = " & A & "D" ^Vth;!o SetEntity eID, entity -U>)B
v89tV9O) Update MA tF, Print "DONE!" =^M Q 4 7mnO60Z8N End Sub -d!84_d9 UBv#z&@[ 如果屈光度是4,光瞳直径是4,则会输出如下数据: 8B6(SQp% clqFV
Accommodation = 4 Diopters .vmCKZ Pupil Diameter = 4 mm Ld:-S,2 Set aqueous humor thickness = 2.81 ;(E]mbV'= Set anterior lens radius = 10.4 and conic constant = -2.375869 'GW~~UhdW Set posterior lens radius = -4.424557 and conic constant = -3.081019 #lFsgb Set lens thickness = 3.927 )sIzBC Set lens index of refraction = 1.42672 .gNJY7`b Set pupil diameter = 4 ;YokPiBy DONE! %[*_-% s#8}&2#l
(文章来源:讯技光电)
|