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简介 $+JS&k/'m 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 r3E!dTDWq !p TJ./ 模型 E`int?C! 5r~#0Zf* 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 6!x&LoM Snp|!e Table 1. AZ眼睛模型的定义 !oPq?lW9 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. Hnknly q<y#pL=k"* 光源 -fhN"B) \B F*m"lz 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 >~%e$a7}+ x:-.+C% XU!2YO)t;! 图1. 光源和提示信息使用 :NJ_n6E 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。 O[tvR:Nh *eI)Z=8 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。 Lbe\@S &'cL%. 图2. 字母F光源的设定方法光 O~j> ? Grs]d-xI 图3. 字母F在视网膜上位置点列图 Z^ }mp@j> 视网膜的散射 f}g\D#`]/ +uay(3m(( 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。 7Q\|=$2 db'/`JeK
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y 图4. 视网膜朗伯散射设定 J+rCxn?;g 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 F,
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%~ 图5. 视网膜重点采样规格设定 g^*<f8 ~d 脚本 W3`>8v1?o 21k5I #U 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: fXrXV~'8 6'\6OsH 图6. 用户对话框的创建与编辑 8DP+W$ 图7. 用户对话框编辑器 s4&^D< 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。 U
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.:@T 余下的脚本计算与屈光度有关的所有参数。 !9 fz(9 j+>J,axU! 分析 Aw&tP[N[ xsWur(> ] 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Y*mbjyt[?X v<Bynd- 图7. 字母F在视网膜上颜色分析 SG6sw]x 脚本代码 ySI~{YVM xf|mlHS+ Option Explicit 'Remove this to enable non-dimensioned variables to be used. %,+leKs 2^?:&1: Dim entity As T_ENTITY >X*Mio8P# Dim op As T_OPERATION
4CGPOc Dim mat As T_MODELMATERIAL NcY608C Dim A As Double 'X shmZ0& Dim pupilDiam As Double N},n `Yl. Dim eID As Long Jx'i2&hGN Dim parID As Long '\jd#Kn'h Dim count As Integer l<M'=-Y Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double mKYeD%Pm* Dim tlens As Double, nlens As Double 6e7{Iy Dim curv As Double, conic As Double N!*_La=TuH Dim ok As Long Z@hD(MS(C aZ\UrV4, Sub Main fu~+8CE. ;5@ t[r '用户输入对话框 SNY~9:;]f Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ~on(3|$ TextBox 220,21,40,21,.TextBox1 'default: 0 }NsUnbxT Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 {3&|tk!* OKButton 40,91,90,21 !
!PYP'e CancelButton 190,91,90,21 {d?$m*YR3` Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Qt|c1@J TextBox 220,49,40,21,.TextBox2 'default: 4 np~~mdmRK End Dialog "s\L~R.& Dim dlg As UserDialog OgX6'E\E
>0l"P"] ok = Dialog (dlg) 7'OtruJ !0N7^Z"gtz If ok=0 Then 'cancel button was pressed s: 3z'4oX Print "Execution cancelled." D-,L&R!` End M,ir`"s End If JgHM?AWg| \e`~i@) ~Z 'Assign accommodation and pupil diameter & use defaults if field left empty 2.d| G` If dlg.TextBox1 = "" Then umdG(osR A = 0 'Default accommodation H{t_xL)k. Else @BNEiOAZ# A = CDbl(dlg.TextBox1) KM`eIw>8 End If *28pRvY:b t!IaUW If dlg.TextBox2 = "" Then bO<CR pupilDiam = 4 'Default pupil diameter X6^},C'E.: Else `SVmQSwO[ pupilDiam = CDbl(dlg.TextBox2) zq%D/H6J, End If Ux+Q ;U_QvN| Print " " \lSU Print "Accommodation = " & A & " Diopters" JAI)Eqqv] Print "Pupil Diameter = " & pupilDiam & " mm" hUm'8)OJ J+f!Ar ' Calculate new parameters with accommodation +&["HoKg}& taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ,6r{VLN RN@ctRS Rant = 12.0 - 0.4*A 'Radius of anterior lens ,k G>?4 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens k#5}\w! 5^j45'%I Rpost = -5.224557 + 0.2*A 'Radius of posterior lens D0BI5q CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 57 #6yXQ
I<A6Z&*un tlens = 3.767 + 0.04*A 'Lens thickness $U/YR&vcw :\=CRaA nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ~/_SMPLo Zc?ppO 'Adjust parameters to account for accommodation j+HHQd7Y P bQk<"J1 '************************************************************************* kkK
kf' 'Aqueous thickness (Position of Lens) (<
=}]v '************************************************************************* |^9BA-nA eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ]f1{n GetCustomElement eID, entity 72,rFYvpK <G*nDFWf parID = FindFullName( "Geometry.Arizona Eye" ) ]@Sj`J[fd f#Xyoa% ' Delete any shift(s) in z $k$4%
7 count = 0 _FwK-?4E- While GetOperationCount(eID)>count }=!,o GetOperation eID, count, op KOwOIDt If op.Type="ShiftZ" Then V"!G2& DeleteOperation eID,count <`0h|m'U count=count-1 0T>H)c6:\ End If Ig5L$bAM~ count=count+1 &
=/ Wend wYlf^~#" %K]euEqs 'Set new shift in W}|'#nR op.Type = "ShiftZ" PH{_,X op.val1 = taq z;u op.parent = parID F H1Z2 AddOperation eID, op ]#.]/f
>- Print "Set aqueous humor thickness = " & taq-0.55 YA&g$! aC<KN:TN6 '************************************************************************* *~/OOH$" 'Radius and conic constant of anterior lens LjU'z# '************************************************************************* =rR~ ` eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ?i`l[+G GetConic eID, entity, curv, conic K|oacOF9 d`1I".y SetConic eID, entity, 1/Rant, CCant |!F5.%PY Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant g&n )fF p^iRPI '************************************************************************* 3 R&lqxhg 'Radius and conic constant of posterior lens wd/<
8>2X '************************************************************************* . <tq61 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) b}Zd)2G GetConic eID, entity, curv, conic q:<{% U$ ujJI
1I SetConic eID, entity, 1/Rpost, CCpost fQP {|+4 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost }(<%`G6N C4}*)a '************************************************************************* }y%oT
P&
'Lens thickness (Position of posterior lens surface) !p1qJ [ '*************************************************************************
U?!>Nd 0 u?{\ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,hVvve,j} apk4j\i?5 ' Delete any z-shift(s) dik9 >*"|o count = 0 *9p |HX= While GetOperationCount(eID)>count 7n90f2"m GetOperation eID, count, op {-A^g!jT& If op.Type="ShiftZ" Then X";@T.ZGut DeleteOperation eID,count _GKB6e% count=count-1 3/#:~a9Q End If -n0C4 kZ2o count=count+1 O+RP3ox" Wend GQ_p-/p
R }$\M{#C~ 'Set new z-shift X w .p op.Type = "ShiftZ" zX#%{#9 op.val1 = tlens ^;c 16 op.parent = parID n8hRaNHl2 AddOperation eID, op VtOZ%h[# Print "Set lens thickness = " & tlens j|tC@0A <|?K%FP7Z '************************************************************************* IHp_A 'Lens index of refraction KQ[!o!% '************************************************************************* ql<rU@ eID = FindMaterial( "Lens" ) LB/C-n.` GetModelMaterial eID, mat l6kmS [Ei1~n)o mat.Nd = nlens VB<Jf'NU SetModelMaterial eID, mat "G:<7oTa Print "Set lens index of refraction = " & nlens V]S1X^ 1T)Zh+?)} '************************************************************************* VzJ5.mRQ 'Pupil diameter
oQ=>'w '************************************************************************* -{
u*qtp eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 1.q_f<U ,^8 MB. 'Adjust pupil diameter (trimming volume inner hole) VGqa)ri" yFhB>i SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" _owjTo} `c+/q2M ' Adjust pupil location to just in front of the lens umLb+GbI4 parID = FindFullName( "Geometry.Arizona Eye" ) xug)aE eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) pb0E@C/R count = 0 )~jqW=d
2 While GetOperationCount(eID)>count :D7|%KK GetOperation eID, count, op 'lZ.j& If op.Type="ShiftZ" Then !AJ]j|@VBd DeleteOperation eID,count @/UfDye count=count-1 iK{T^vvk End If }`yiT<z count=count+1 s/Xb^XjS1 Wend &L^CCi op.Type = "ShiftZ" &6Il(3-^ op.val1 = taq-0.01 #0;HOeIiH op.parent = parID zX{ .^| AddOperation eID, op ESb
]}c: $j)hNWI Print "Set pupil diameter = " & pupilDiam X5
ITF)& E2B>b[ 'Update AZ Eye subassembly Description 8dK0o>|} eID = FindFullName( "Geometry.Arizona Eye" ) *^ \FIUd GetEntity eID, entity uIMe entity.Description = "Accommodation = " & A & "D" S'B6jJK2x SetEntity eID, entity >5T_g2pkv `:M^8SYrL Update nU`Lhh8y Print "DONE!" ji+{ :D a <X0e> End Sub W4YE~ (Y(E% 如果屈光度是4,光瞳直径是4,则会输出如下数据: dRvin[R8 .I$}KE) Accommodation = 4 Diopters q 6`G I6 Pupil Diameter = 4 mm }jF+`!*! Set aqueous humor thickness = 2.81 GJ'spgz Set anterior lens radius = 10.4 and conic constant = -2.375869 3kmeD". Set posterior lens radius = -4.424557 and conic constant = -3.081019 ep(g`e Set lens thickness = 3.927 VF0dE Set lens index of refraction = 1.42672 8n4V
cu Set pupil diameter = 4 #G3N(wV3 DONE! /-0'
Qa+* TOI4?D] (文章来源:讯技光电)
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