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2016-02-24 12:53 |
FRED运用:Arizona眼睛模型
简介 sOJ"~p 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。 U7x}p^B9\N 3Q`'C7Pi 模型 h r6f}2 +}9%Duim 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。 yx/:<^"-$ uvA}7L{UO
Table 1. AZ眼睛模型的定义 [attachment=67931] O~aS&g/sf 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. 1YnDho;~ $ /wr? 光源 wRie{Vk tO~H/0 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。 7%w4?Nv3I ,9+@\ 0W=IuPDU
[attachment=67932] 图1. 光源和提示信息使用 i,RK0q?> 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。 89 (k<m ]Uxx_1$, 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。 $k!@e M/R U_I'Nz!^t
[attachment=67933] 图2. 字母F光源的设定方法光 f4w| TD3R/NP
[attachment=67934] 图3. 字母F在视网膜上位置点列图 EKoCm)}d 视网膜的散射 Jge;/f!i PiH#9XB 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 3rR(>}:[V }){hQt7 Qgf_
[attachment=67935] 图4. 视网膜朗伯散射设定 Q6vkqu5!= 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 jJ?3z,h VNytK_F0P sHEISNj/^
[attachment=67936] 图5. 视网膜重点采样规格设定 +qS$t 脚本 fYCAwS{ eN jC.w9 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: jliKMd<? (iS94}-)
[attachment=67937] 图6. 用户对话框的创建与编辑 e94csTh=
[attachment=67938] 图7. 用户对话框编辑器 o^AK@\e:^Z 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。
Y@.:U* 余下的脚本计算与屈光度有关的所有参数。 $!fz87-p> m$O@+;>l 分析 (cCB3n\20 beIEy(rA 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 >)VrbPRuA
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[attachment=67939] 图7. 字母F在视网膜上颜色分析 * |,V$ 脚本代码 wPG3Ap8L q+m&V#FT% Option Explicit 'Remove this to enable non-dimensioned variables to be used. x&?35B
i b9\=NdyCY Dim entity As T_ENTITY (oTx*GP>Y Dim op As T_OPERATION S*\`LBl"nX Dim mat As T_MODELMATERIAL i@g6%V= Dim A As Double cPtP?)38. Dim pupilDiam As Double `#l_`j=r$ Dim eID As Long 5$O@+W!?@ Dim parID As Long Z~P5SEg Dim count As Integer (2a~gQGD Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Zo&U3b{Dy Dim tlens As Double, nlens As Double CP={|]>+S Dim curv As Double, conic As Double 5SK.R;mn Dim ok As Long IXC: Q
US
Q{o Sub Main
w1iQ#.4K_ `|]juc '用户输入对话框 >B3_P4pW9 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 sM-k,0z TextBox 220,21,40,21,.TextBox1 'default: 0 wRWN]Vo Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 E7 7Au;TL OKButton 40,91,90,21 *d)B4qG CancelButton 190,91,90,21 wt RAq/ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 3:76x TextBox 220,49,40,21,.TextBox2 'default: 4 DuCq16'0T End Dialog ==Y^~ab;K Dim dlg As UserDialog rVZkG,Q G`TO[p]q ok = Dialog (dlg) [Si`pPvl GV%ibqOpQj If ok=0 Then 'cancel button was pressed hL&z"_` Print "Execution cancelled." U?.VY@ End `qUmOFl End If HPu nNsA fkYa 'Assign accommodation and pupil diameter & use defaults if field left empty zvSfW#
* If dlg.TextBox1 = "" Then Knn$<!> A = 0 'Default accommodation 0naegy?, Else mGoUF$9 k A = CDbl(dlg.TextBox1) iao_w'tJ End If 6&h,eQ! ky[FNgQ3n If dlg.TextBox2 = "" Then Xi$uK-AHpj pupilDiam = 4 'Default pupil diameter m[%&KW( Else nww,y pupilDiam = CDbl(dlg.TextBox2) 7TlOF End If a^|mF#
z 9D-PmSnv Print " " ])vM# f Print "Accommodation = " & A & " Diopters" z!?xz Print "Pupil Diameter = " & pupilDiam & " mm" [?_^Cy 5Vf#(r f ' Calculate new parameters with accommodation @7.Ews5Mke taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 0riTav8 8*6U4R Rant = 12.0 - 0.4*A 'Radius of anterior lens .y|* CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens yA=#Ji F d *p3a Rpost = -5.224557 + 0.2*A 'Radius of posterior lens l2z@t3{ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens }zj_Pp "){"{~ tlens = 3.767 + 0.04*A 'Lens thickness arRbq!mO ?>DN7je nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction #8rLB( FAo\`x 'Adjust parameters to account for accommodation HZ )z^K?1 XeJn,= '************************************************************************* 3Vs8"BFjz 'Aqueous thickness (Position of Lens) 1Sx2c '************************************************************************* 9x23## s eID = FindFullName( "Geometry.Arizona Eye.Lens" ) |!,;IoZ GetCustomElement eID, entity h b_"E, `F k_/*>lIZY parID = FindFullName( "Geometry.Arizona Eye" ) =YOq0 ,F!zZNW9 ' Delete any shift(s) in z }k~ih?E^s count = 0 !%?O`+r While GetOperationCount(eID)>count /R!:l l2 GetOperation eID, count, op ~5q1zr)E If op.Type="ShiftZ" Then ot($aY,t DeleteOperation eID,count <Y:{>= count=count-1 wQEsq< End If
kc-=5l count=count+1 #p*D.We Wend -U.>K,M F2QFQX(j 'Set new shift in x+EkL3{ op.Type = "ShiftZ" <A^sg?s<' op.val1 = taq %|AebxB'o op.parent = parID O`K2mt\% AddOperation eID, op N:x--,2 Print "Set aqueous humor thickness = " & taq-0.55 J2adG+= _wH>h$E '************************************************************************* %PM&`c98z7 'Radius and conic constant of anterior lens dhv?36uE '************************************************************************* r2yJ{j&s eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) n+MWny GetConic eID, entity, curv, conic Ql"kJ_F!br oq${}n < SetConic eID, entity, 1/Rant, CCant 2. '` mGu Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant g&z8t;@ V^Y'!w\LGI '************************************************************************* /s*.:cdH 'Radius and conic constant of posterior lens u}3D'h '************************************************************************* ZP{<f~; eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) h?[|1.lJx( GetConic eID, entity, curv, conic !6!Gx: )G#mC0?PV SetConic eID, entity, 1/Rpost, CCpost 76H>ST@G| Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost f7YBhF '_d4[Olu '************************************************************************* Yw] 7@ 'Lens thickness (Position of posterior lens surface) !7Eodq-0 '************************************************************************* 0FSN IPx J0V`sK parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 3ew4QPT' vjjVZ ' Delete any z-shift(s) qv& Bai[ count = 0 ZDg(D" While GetOperationCount(eID)>count @A4$k
dJ2 GetOperation eID, count, op &AN1xcx\ If op.Type="ShiftZ" Then Nv=78O1 DeleteOperation eID,count m _cRK}> count=count-1 ^/_Yk.w End If F~q(@.b count=count+1 _%q~K (:: Wend k&2=-qgVR 85YUqVi9 'Set new z-shift >H^#!eaqw op.Type = "ShiftZ" |lt]9>| op.val1 = tlens >`r3@|UY op.parent = parID Z\?2"4H AddOperation eID, op dgL>7X=7 Print "Set lens thickness = " & tlens 9 w$m\nV g5
T '************************************************************************* W:,Wex^9n 'Lens index of refraction -Arsmo '************************************************************************* h);^4cU eID = FindMaterial( "Lens" ) t;BUZE_!0c GetModelMaterial eID, mat 1rJ2}d\y w9{C"K?u= mat.Nd = nlens LRVcf SetModelMaterial eID, mat y(o)}m*0 Print "Set lens index of refraction = " & nlens GlnO8cAB `J1HQ!Z '************************************************************************* |~r-VV(= 'Pupil diameter kk%3 2(By '************************************************************************* ]I [~0PCSX eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) z%OKv[/N )\|+G5#` 'Adjust pupil diameter (trimming volume inner hole) &W,jR|B
g:>'+(H ; SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" G@.MP|
2 T1]?E]m{ ' Adjust pupil location to just in front of the lens 6Q^~O*cw parID = FindFullName( "Geometry.Arizona Eye" ) n:,mo} ?X eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) t
N{S;)q#X count = 0 &}r"Z?f) While GetOperationCount(eID)>count J0?kEr GetOperation eID, count, op Ut;`6t If op.Type="ShiftZ" Then Zz0e4C DeleteOperation eID,count Y3Fj3NwS count=count-1 |5bLV^mv]i End If d'RvpoM count=count+1 X` zWw_i Wend <7M-?g:vj op.Type = "ShiftZ" Snx!^4+MF op.val1 = taq-0.01 EU$.{C_O( op.parent = parID s_'&_>D AddOperation eID, op gcU*rml ;f[lq^eV Print "Set pupil diameter = " & pupilDiam Fl-\{vOn @1MnJP 'Update AZ Eye subassembly Description 7;s#QqG`I eID = FindFullName( "Geometry.Arizona Eye" ) `gX@b^ GetEntity eID, entity 0f^{Rp6 entity.Description = "Accommodation = " & A & "D" c+ oi8G SetEntity eID, entity >?, Zn *'?7OL Update /ad9Q~nJ Print "DONE!" =l/6-j^ p;O%W@n" End Sub J@s>Pe) v1.3gzR 如果屈光度是4,光瞳直径是4,则会输出如下数据: ffZ~r%25{ o4);5~1l Accommodation = 4 Diopters G0E5Y;YIN$ Pupil Diameter = 4 mm vADiW~^Q^ Set aqueous humor thickness = 2.81 c$O8Rhx Set anterior lens radius = 10.4 and conic constant = -2.375869 :?>7Z6 Set posterior lens radius = -4.424557 and conic constant = -3.081019 '<R>cN" Set lens thickness = 3.927 \$ytmtf5 Set lens index of refraction = 1.42672 e$# *t Set pupil diameter = 4 4:`D3 DONE! ghk=` !yKw IS2cU'
(文章来源:讯技光电)
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