Arizona眼睛模型
简介 OWewV@VXR /Ot3[B 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。 z='%NZY r"2lcNE 模型 Mm@G{J\\ Z|E9}Il] 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>wN
O kAEq +{h
Table 1. AZ眼睛模型的定义 I*N"_uKU 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. /3aW 0/^o x\G% 光源 I #1~CbR E_=F'sP? 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。 E\!X$ I.3~ctzu '{2]:
图1. 光源和提示信息使用 ,)[9RgsE 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。 C^"zU>W_ T$lV+[7 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 3l<qcKKc 3FR(gr$X
图2. 字母F光源的设定方法光 ,7j8+p|}, jlP*RX
图3. 字母F在视网膜上位置点列图 !-OZ/^l|O` 视网膜的散射 INr1bAe$ M]PZwW8 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。 yo#r^iAr 5Qq/nUR Nb$0pc1J<
图4. 视网膜朗伯散射设定 ,RR{Y- 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 HZAT_ u*@R`,Y
+JtK VF
图5. 视网膜重点采样规格设定 `;}`>!8j 脚本 3tf_\E+mIi u9@B& 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: cIw X sx
sR9$=91`
图6. 用户对话框的创建与编辑 3`reXms*{
图7. 用户对话框编辑器 ~k&b 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。 Sqn>L`Lz 余下的脚本计算与屈光度有关的所有参数。 \]<R`YMV bpBn3f`?* 分析 e=(Y,e3 o)5zvnu7 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 VkJ">0k nCi
]6;Y
图7. 字母F在视网膜上颜色分析 ~JT2el2W7p 脚本代码 xK6`|/e +
-Rf@ Option Explicit 'Remove this to enable non-dimensioned variables to be used. P{)D_Bi y7UU'k` Dim entity As T_ENTITY c)#7T<>*' Dim op As T_OPERATION z~h?"' Dim mat As T_MODELMATERIAL ~}b0zL Dim A As Double G06;x Dim pupilDiam As Double 7310'wc Dim eID As Long >;Hx<FKxP Dim parID As Long }SWfP5D@ Dim count As Integer A>gZl)c Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double .fzyA5@l Dim tlens As Double, nlens As Double AVjRhe Dim curv As Double, conic As Double =Lkn
Dim ok As Long UUfM7gq g5|&6+t. Sub Main ^4`x:6m CCG5:xS '用户输入对话框 M%_*vD Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 /UunWZ u% TextBox 220,21,40,21,.TextBox1 'default: 0 "}_J"% Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 }'Ap@4 OKButton 40,91,90,21 liYsUmjZ= CancelButton 190,91,90,21 3Y# Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ^*l
dsc TextBox 220,49,40,21,.TextBox2 'default: 4 \9,lMK[b End Dialog O83J[YuzjN Dim dlg As UserDialog =b$g_+ #tZ!D^GQHq ok = Dialog (dlg) 9QP= 4e>f}u5 If ok=0 Then 'cancel button was pressed 5)f 'wVe Print "Execution cancelled." x3Cn:F End D>jtz2y=D End If eHUyV@ EB&hgz&_ 'Assign accommodation and pupil diameter & use defaults if field left empty [cDDZ+6 If dlg.TextBox1 = "" Then B>E4," A = 0 'Default accommodation }2LG9B% Else 3q/"4D A = CDbl(dlg.TextBox1) O=U,x-Wl End If =55)|$hgD a`yCPnB( If dlg.TextBox2 = "" Then qDGx(d pupilDiam = 4 'Default pupil diameter @; 9KP6d Else :@&e~QP( pupilDiam = CDbl(dlg.TextBox2) $o+@}B0) End If K
@&c Ke^/aGi}O Print " " EIzTbW{p Print "Accommodation = " & A & " Diopters" hFoeVM[h Print "Pupil Diameter = " & pupilDiam & " mm" tPiC?=4R nZj&Ma7R ' Calculate new parameters with accommodation 3U?gw!M> taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness r9}(FL/)b b/.EA'/ Rant = 12.0 - 0.4*A 'Radius of anterior lens w@WtW8
p^ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens %m lH zLr:zf l Rpost = -5.224557 + 0.2*A 'Radius of posterior lens w,6gnO CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens @QJPcF" vKoQ!7g tlens = 3.767 + 0.04*A 'Lens thickness -;Mh|!yg 0p3) t nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction uAYDX<Ja9 s;<]gaonB_ 'Adjust parameters to account for accommodation zwUZ*Se BpFXe7 '************************************************************************* D@w&[IF 'Aqueous thickness (Position of Lens) NB3+kf , '************************************************************************* 2bXCFv7} eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ]S(nA!] GetCustomElement eID, entity C]ho7qC j5hQ;~Fa| parID = FindFullName( "Geometry.Arizona Eye" ) )@B! SPTx-b[ ' Delete any shift(s) in z iU{\a, count = 0 Ei,dO;& While GetOperationCount(eID)>count MkZoHzg}c GetOperation eID, count, op KdlUa^}D If op.Type="ShiftZ" Then FzsW^u+ DeleteOperation eID,count IL&R&8' count=count-1 A{{rNbCK End If o 8^!wGY count=count+1 (F R Wend R=NK3iGT f *bcemH8f 'Set new shift in v~^*L iP+ op.Type = "ShiftZ" .Pe^u%J6F op.val1 = taq 0}_1ZU op.parent = parID 4GJx1O0Ol AddOperation eID, op OJ\j6owA Print "Set aqueous humor thickness = " & taq-0.55 =6'D/| 3 tpV61L
'************************************************************************* dm83YCdL 'Radius and conic constant of anterior lens a,t]> z95 '************************************************************************* 8
=3#S'n eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) d$D3iv^hyx GetConic eID, entity, curv, conic f xD|_ f,+ONV]5Tt SetConic eID, entity, 1/Rant, CCant XKBQH( Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #Nv0d|0\ [+dTd2uZ<\ '************************************************************************* s\
]Rgi>w 'Radius and conic constant of posterior lens 9jUm0B{? '************************************************************************* lgCOp%> eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 1z8AK"8 GetConic eID, entity, curv, conic O;;vz+ j D7N` %A8 SetConic eID, entity, 1/Rpost, CCpost K@=_&A! Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost `{@?O%UB ])T_&% '************************************************************************* u $T'#p1
'Lens thickness (Position of posterior lens surface) !8%{(;( '************************************************************************* p~u11rH CY8=prC parID = FindFullName( "Geometry.Arizona Eye.Lens" ) @ GzN0yXhR ~Ywt o ' Delete any z-shift(s) KA{Y*m^7 count = 0 6n.C!,Zmn While GetOperationCount(eID)>count qg-?Z,EB GetOperation eID, count, op 5zII4ukn* If op.Type="ShiftZ" Then $Xo_C_:B DeleteOperation eID,count =kWm9W<^ count=count-1 H!{Cr#= End If J3=^+/g count=count+1 sJ/?R: Wend bX]$S 5c_u yu62$d 'Set new z-shift \c$!C8z op.Type = "ShiftZ" "^@0zy@x op.val1 = tlens 9G}Crp op.parent = parID TL_8c][.4$ AddOperation eID, op H`ZUI8- Print "Set lens thickness = " & tlens `BHPjp> owc#RW9 7 '************************************************************************* zpd Z. 'Lens index of refraction KGb3n;] '************************************************************************* R`|GBVbv eID = FindMaterial( "Lens" ) U.QjB0; GetModelMaterial eID, mat t.oP]_mI lGr(GHn mat.Nd = nlens @RF!p SetModelMaterial eID, mat ]`Y;4XR Print "Set lens index of refraction = " & nlens 5*pCb,z>q $n?@zd@53 '************************************************************************* GoNX\^A 'Pupil diameter BI-xo}KI '************************************************************************* f#UT~/~bL2 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Ey!+rq} Yl#r9TM 'Adjust pupil diameter (trimming volume inner hole) Rc H",*U AA$-Lx(UJk SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" />zE$)'M >;.'$- ' Adjust pupil location to just in front of the lens |,89zTk' parID = FindFullName( "Geometry.Arizona Eye" ) a$SGFA}V eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) _"B5S?
count = 0 +," /z\QO While GetOperationCount(eID)>count
.* xaI+: GetOperation eID, count, op iIoeG_^*Y If op.Type="ShiftZ" Then Wo@0yF@ DeleteOperation eID,count 257pO9] count=count-1 Vn-y<*np End If |A#pG^ count=count+1 ?E0j)P/
( Wend pAo5c4y!4 op.Type = "ShiftZ" hX~d1.]Y op.val1 = taq-0.01 x_vaYUl) op.parent = parID #,1Kum
bG3 AddOperation eID, op dtw4cG +KV`+zic+ Print "Set pupil diameter = " & pupilDiam ?6F\cl0. tB_GEt2M 'Update AZ Eye subassembly Description e:E:"elr] eID = FindFullName( "Geometry.Arizona Eye" ) FDA``H~ GetEntity eID, entity QQUYWC entity.Description = "Accommodation = " & A & "D" oZkjg3 SetEntity eID, entity A&OU;j] w]hs1vch Update ao]Dm#HiO Print "DONE!" 9H9 P'lx9 WKib$(%f6 End Sub F/FUKXxx }]ak6'|[ 如果屈光度是4,光瞳直径是4,则会输出如下数据: "/e:V-W
6\7bE$K Accommodation = 4 Diopters v"VpE`z1# Pupil Diameter = 4 mm ~.?,*q7 Set aqueous humor thickness = 2.81 yF-EHNNf Set anterior lens radius = 10.4 and conic constant = -2.375869 IvFxI#.ju Set posterior lens radius = -4.424557 and conic constant = -3.081019 d7.}=E.L Set lens thickness = 3.927 (*>%^ C? Set lens index of refraction = 1.42672 $^F
L*w Set pupil diameter = 4 iYi3x_A` DONE! fz[o;GTc
|