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- >AI65g 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。 #@Yw]@5M $TS4YaJ% 模型 +]P??`,R; Z}6 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 nn!W-Bsqjh =n|n%N4Y Table 1. AZ眼睛模型的定义 S,,,D+4 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. )e`$'y@L$ (<!Yw|~ 光源 :G\f(2@ "b5:6\ 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。 }S|~^
P 0v&*y3Y '=}F}[d"kk 图1. 光源和提示信息使用 'N#,,d/G 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。 qg6283'? ib8@U}Vn1 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。 5> M6lwS ibo{!>m 图2. 字母F光源的设定方法光 R,?7|x v8Gm;~ 图3. 字母F在视网膜上位置点列图 /f2HZfj 视网膜的散射 4sOo>.<x X;/~d>@ 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。 70IBE[T& |c,,*^ C,$$bmS= 图4. 视网膜朗伯散射设定 HC4qP9Gs 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。 _GSl}\ f&x7g. I _Eo$V& 图5. 视网膜重点采样规格设定 G*.}EoA 脚本 {1a%CsCM HAJK%zLc 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: KneCMFy ;s
m )f 图6. 用户对话框的创建与编辑 ]Q-*xho 图7. 用户对话框编辑器 ?QuD:vck 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 4 0as7.q 余下的脚本计算与屈光度有关的所有参数。 1#BMc% ;Gf,$dbWn 分析 @ov*Fh ^i>Tm9vM 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 t;g=@o9YA z2:^Qg 图7. 字母F在视网膜上颜色分析 >p"ytRu^ 脚本代码 LDilrG)
V80BO#Pk Option Explicit 'Remove this to enable non-dimensioned variables to be used. @,btQ_'X "`;$wA Dim entity As T_ENTITY K)!yOa'fH Dim op As T_OPERATION i}d^a28 Dim mat As T_MODELMATERIAL 7OSk0%Q, Dim A As Double };{V]f 0 Dim pupilDiam As Double Lh eOGM Dim eID As Long P_Rh& gkuK Dim parID As Long 7{0;<@ Dim count As Integer [N]5)n Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double iKs @oHW Dim tlens As Double, nlens As Double NrQGoAOw Dim curv As Double, conic As Double Ll4/P[7:? Dim ok As Long "N'|N., O"%b@$p\L Sub Main xw[KP [( ]Dj,8tf`H '用户输入对话框 {,V .IDs8[ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ,ddoII TextBox 220,21,40,21,.TextBox1 'default: 0 _Z9HOl@ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 t]dtBt].: OKButton 40,91,90,21 v D"4aw CancelButton 190,91,90,21 ~cC=DeX Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 B4fMD] TextBox 220,49,40,21,.TextBox2 'default: 4 2VB|a;Mo End Dialog +hoZW R Dim dlg As UserDialog {,
+,:w7 'IVNqfC)u ok = Dialog (dlg) 8OV;&Z,x K=S-p3\g If ok=0 Then 'cancel button was pressed 7sgK+
ip Print "Execution cancelled." X*4iNyIs_ End #Tm^$\*h\] End If =t@8Y`9w F@4TD]E0^ 'Assign accommodation and pupil diameter & use defaults if field left empty {Y0Uln5u If dlg.TextBox1 = "" Then 1u9*)w A = 0 'Default accommodation =x_~7 Xc{ Else IF>dsAAI< A = CDbl(dlg.TextBox1) Vn7FbaO^ End If aRt`IcZYz -XuRQ_)nG If dlg.TextBox2 = "" Then 6!QY)H^j9, pupilDiam = 4 'Default pupil diameter uD'GI Else AbqeZn pupilDiam = CDbl(dlg.TextBox2) 8ch^e[U` End If [unK5l4_! \ytF@"7 Print " " KR49Y>s< Print "Accommodation = " & A & " Diopters" `jI$>{oa Print "Pupil Diameter = " & pupilDiam & " mm" cN{(XmX5n q3_ceXYU ' Calculate new parameters with accommodation WUN|,P`b taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness XA1gV>SJ @2X{e7+D Rant = 12.0 - 0.4*A 'Radius of anterior lens [5"F=tT7WP CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens AlVBhR` >14x.c Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Z?@oe-mz CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens i(hL6DLD F4b$ tlens = 3.767 + 0.04*A 'Lens thickness n7>L&?N#y# F{'lF^Dc nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction K}OY!| 9 SBVp6' 'Adjust parameters to account for accommodation ;A\SbLM Yg~$1b@ '************************************************************************* y\C_HCU H 'Aqueous thickness (Position of Lens) W Z_yaG$U '************************************************************************* uOv0ut\\G eID = FindFullName( "Geometry.Arizona Eye.Lens" ) F5+)=P# GetCustomElement eID, entity VhfMj| 'ZiTjv] parID = FindFullName( "Geometry.Arizona Eye" ) CGp7 Tx # _U<r@ ' Delete any shift(s) in z Wcf;ZX count = 0 JtbwY@R While GetOperationCount(eID)>count nf2[hx@=U GetOperation eID, count, op @dHQ}Ni If op.Type="ShiftZ" Then "NMSLqO DeleteOperation eID,count N!Cy)HnS\w count=count-1 YD@n8?~$$ End If ],l}J'.8<V count=count+1 6!|/(~ Wend i^Ip+J+[ a0/[L 'Set new shift in d95 $w8> op.Type = "ShiftZ" -|WQs'%O op.val1 = taq {kdS t1 op.parent = parID `JZ`j7f AddOperation eID, op (j%;)PTe+& Print "Set aqueous humor thickness = " & taq-0.55 $:u5XJx nvOJY6)$V '************************************************************************* ZDl6F` 'Radius and conic constant of anterior lens ^!j,d_)b! '************************************************************************* c*N>7IF, eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) H3Zsm)+: GetConic eID, entity, curv, conic Fs 95^T (DTXc2)c SetConic eID, entity, 1/Rant, CCant lWRRB&8 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 6^#@y|. TJ`Jqnh '************************************************************************* [:"7B&&A 'Radius and conic constant of posterior lens tvEf-z '************************************************************************* ,+U,(P5>s eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Ra-%,cS GetConic eID, entity, curv, conic M\L^ Wf9 T8US` MZ SetConic eID, entity, 1/Rpost, CCpost 56l1&hp8In Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost %]\IC(q G5hh$Nmpi '************************************************************************* %7[Z/U= 'Lens thickness (Position of posterior lens surface) 4lsg%b6_%, '************************************************************************* grbUR)f<?- s F!nSr parID = FindFullName( "Geometry.Arizona Eye.Lens" ) >oasA2S P; DGs]PF ' Delete any z-shift(s)
WgayH count = 0 "qxu9Hg! While GetOperationCount(eID)>count N799@:. GetOperation eID, count, op
M_ii If op.Type="ShiftZ" Then a%NSL6 DeleteOperation eID,count m6iQB\ \ count=count-1 %DIZgPd\ End If k]] e8> count=count+1 |4?O4QN Wend Fo$'*(i )|Xi:Zd5> 'Set new z-shift p)y'a+|7 op.Type = "ShiftZ" E(/M?>t- op.val1 = tlens se]q~<& op.parent = parID ]<g`rR7} AddOperation eID, op #z&@f Print "Set lens thickness = " & tlens fXfO9{E )DwHLaLW '************************************************************************* IuN:*P 'Lens index of refraction c@<vFoq '************************************************************************* :o=a@Rqx eID = FindMaterial( "Lens" ) HCOE'24I GetModelMaterial eID, mat )D>= \Me &vHfuM` mat.Nd = nlens S*9qpes-m| SetModelMaterial eID, mat Kjfpq!NYE Print "Set lens index of refraction = " & nlens ReZ&SNJ V0)F/qY '*************************************************************************
~uRL+<.c 'Pupil diameter r.#"he_6!. '************************************************************************* k%2Rv4)hU eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) = k7}[!T i?D
KKjN$ 'Adjust pupil diameter (trimming volume inner hole) ai@hQJ* 'pQ\BH SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" b@?pofZ`k V+- ]txu| ' Adjust pupil location to just in front of the lens ,[{Z_co parID = FindFullName( "Geometry.Arizona Eye" ) p"k[ac{ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ^Z`?mNq9 count = 0 Qk h}=3u While GetOperationCount(eID)>count XJ{b_h#N GetOperation eID, count, op -er8(snDQ If op.Type="ShiftZ" Then 'BmLR{[2L DeleteOperation eID,count e=#'rDm count=count-1 i3v|r 0O~L End If W &HF*Aw count=count+1 ]46#u=y~3 Wend X\
bXat+ op.Type = "ShiftZ" c
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op.val1 = taq-0.01 s?pd&_kOv3 op.parent = parID K%iA-h AddOperation eID, op 2SHS!6:Rl =&YhA}l\O Print "Set pupil diameter = " & pupilDiam sBV})8]KM {IR-g,B 'Update AZ Eye subassembly Description 71(C@/J eID = FindFullName( "Geometry.Arizona Eye" ) RhQ[hI GetEntity eID, entity T=D|jt entity.Description = "Accommodation = " & A & "D" Gr}lr gP S SetEntity eID, entity c3]X#Qa#m$ 5*P+c(= Update 0kOl,%Ey Print "DONE!" DSX.84 OD~B2MpM> End Sub C]'ru N`1W"Rx! 如果屈光度是4,光瞳直径是4,则会输出如下数据: 8{ooLdpX7 g*%z{w Accommodation = 4 Diopters f tE2@} Pupil Diameter = 4 mm =/zb$d cz Set aqueous humor thickness = 2.81 _dk/SWb) Set anterior lens radius = 10.4 and conic constant = -2.375869 k 3S Set posterior lens radius = -4.424557 and conic constant = -3.081019 P<s0f:". Set lens thickness = 3.927 lU&[){ Set lens index of refraction = 1.42672 ;I@@PUnR Set pupil diameter = 4 ~+OAAkJ9 DONE! ZA {T0: \Jy/
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