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$MR3@e 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 akr2Os +8Q @R)3 模型 }(u:K}8 r-$xLe7a 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。 Xykoq"dbb MMKN^a"GA Table 1. AZ眼睛模型的定义 v]on0Pi! 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. &Wa3/mWK 9F3, 光源 NbU4|Oi z{ eZsh
b 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。 vd#)+ `)8~/G% DjK7_'7(L 图1. 光源和提示信息使用 Sw E7U~ 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。 .yfp-n4H Brs6RkRf 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。 (kO (R#M sS{Co8EJn 图2. 字母F光源的设定方法光 RICm$, \e4AxLP 图3. 字母F在视网膜上位置点列图 e)?}2 视网膜的散射 C1_0 9Vc C=oeRc'r1W 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 l:@=9Fp> 6;Z`9PGp OT$Ne 图4. 视网膜朗伯散射设定 ~v\
W[ 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。 QlB9m2XB .
U6(>6- mYo~RXKGF 图5. 视网膜重点采样规格设定 }[|9vF"g.y 脚本 |$IL:W6 |)>+&
xk 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: hC"'cUrcN iTdamu`L 图6. 用户对话框的创建与编辑 om`B:=+ 图7. 用户对话框编辑器 Zl9 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。 j<!dpt 余下的脚本计算与屈光度有关的所有参数。 qm/>\4eLt $LuU 分析 $2*_7_Qb qY%|Uo 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 s%R,]q k*2khh- 图7. 字母F在视网膜上颜色分析 ,aezMbg 脚本代码 xC9?rLUZ `"ks0@^U Option Explicit 'Remove this to enable non-dimensioned variables to be used. ;lE=7[UJ3X 7wW x 8 Dim entity As T_ENTITY TT(R<hL Dim op As T_OPERATION Pw]+6 Dim mat As T_MODELMATERIAL -J6` Dim A As Double a3M I+ Dim pupilDiam As Double .?APDr"QQH Dim eID As Long )d3C1Pd> Dim parID As Long (p#c p Dim count As Integer ~kV>nx2 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double *wx%jbJo Dim tlens As Double, nlens As Double $ Lfbt=f Dim curv As Double, conic As Double 8q]"CFpa Dim ok As Long H~#$AD+H QPp31o.!5 Sub Main C[Q4OAFG %$b}o7U"s '用户输入对话框 &?p(UY7'" Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 =os!^{p7> TextBox 220,21,40,21,.TextBox1 'default: 0 8MDivr/@ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 p)Q5fh0- OKButton 40,91,90,21 {G3Ok++hc CancelButton 190,91,90,21 uIO?4\s&G Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 J80&npsO TextBox 220,49,40,21,.TextBox2 'default: 4 i4> M End Dialog z7?SuJ Dim dlg As UserDialog njJTEUd"> lBG=jOS ok = Dialog (dlg) KRd'!bG=1 R86i2', If ok=0 Then 'cancel button was pressed 6*$A/D Print "Execution cancelled." EGv]K| End qh}+b^Wi End If .i )K#82 :rufnmsP<U 'Assign accommodation and pupil diameter & use defaults if field left empty @JdeOL; If dlg.TextBox1 = "" Then l_04b]; A = 0 'Default accommodation ,'YKL", Else 2\64~a^ A = CDbl(dlg.TextBox1) %sZ3Gpi End If elKp?YN d7g$9&/q If dlg.TextBox2 = "" Then +DefV,Ny pupilDiam = 4 'Default pupil diameter JY:Fu Else ".AW pupilDiam = CDbl(dlg.TextBox2)
rKOa9M End If JB5%\ )2d1@]6# Print " " X}={:T+6s Print "Accommodation = " & A & " Diopters" 753gcY#i Print "Pupil Diameter = " & pupilDiam & " mm" lxD~l#)^ln M`=\ijUwN ' Calculate new parameters with accommodation $b^ niL taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness x) %"i) &Nr+-$ Rant = 12.0 - 0.4*A 'Radius of anterior lens v'`qn CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens sy(bL_% ^^uY)AL Rpost = -5.224557 + 0.2*A 'Radius of posterior lens (?T{^Hg CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Um-Xb'R*]V 3S>rc0]6 tlens = 3.767 + 0.04*A 'Lens thickness %qrUP\rn h3\(660>$ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction n
sN n>{ pK>/c>de 'Adjust parameters to account for accommodation \G/ZA) t 8<6@O '************************************************************************* `5x0p a 'Aqueous thickness (Position of Lens) h6`VU`pPI '************************************************************************* ^{8CShUCv eID = FindFullName( "Geometry.Arizona Eye.Lens" ) IK4(r / GetCustomElement eID, entity *ZRk) Ka)aBU9 parID = FindFullName( "Geometry.Arizona Eye" ) *r~6R F5UHkv"K&O ' Delete any shift(s) in z JNvgUb'U count = 0 b'/:e#F While GetOperationCount(eID)>count KeyHxU=? GetOperation eID, count, op U+D# If op.Type="ShiftZ" Then eXLdb- DeleteOperation eID,count U~zy;MT count=count-1 5Ktll~+:# End If `J{{E,y
@ count=count+1 "KC3+:tm Wend ?WS.RB e2 us:v/WTQ 'Set new shift in {FC<vx{42 op.Type = "ShiftZ" *`bES V
: op.val1 = taq +).=}.k op.parent = parID 0@&;JMh6< AddOperation eID, op !.q#X^@>L Print "Set aqueous humor thickness = " & taq-0.55 _|{pO7x]oG v,3}YDu '************************************************************************* IMy!8$\u 'Radius and conic constant of anterior lens $qoal '************************************************************************* !0X"^VB eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) !83 N#Y_Mz GetConic eID, entity, curv, conic p+2%LYR u ^(qR({cX SetConic eID, entity, 1/Rant, CCant [S.zWPX9{ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant p5nrPL z5f3T D6, '************************************************************************* Yka>r9wr 'Radius and conic constant of posterior lens VhgcvS@V '************************************************************************* X5Y. o& eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) LXc;`] GetConic eID, entity, curv, conic q6
4bP4K PB{5C*Y7^k SetConic eID, entity, 1/Rpost, CCpost 2m&?t_W Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost #
o\&G@e} w/fiNY5FZ '************************************************************************* t |:XSJ9 'Lens thickness (Position of posterior lens surface) |'L$ogt6 '************************************************************************* /cD]m 3-![%u parID = FindFullName( "Geometry.Arizona Eye.Lens" ) _ [hVGCSB uKT\\1Jrq ' Delete any z-shift(s) H"V)dEm count = 0 BQ!_i*14+ While GetOperationCount(eID)>count <$nMqUu0 GetOperation eID, count, op z&|sks7 If op.Type="ShiftZ" Then <2w41QZX DeleteOperation eID,count lIatM@gU count=count-1 s:sk`~2<gd End If W TC/mcS count=count+1 0t00X/ Wend z-kB!~r pH?"@ 'Set new z-shift /.1h_[K] op.Type = "ShiftZ" O~F8lQ op.val1 = tlens ZV:0:k.x op.parent = parID N..@}} AddOperation eID, op 1ZfhDtK( Print "Set lens thickness = " & tlens Zu^J X/um ].
^e[v6 '************************************************************************* TUR2|J@n 'Lens index of refraction _
3jY,* '************************************************************************* Ni61o?]Nj eID = FindMaterial( "Lens" ) MSS0Sx<f GetModelMaterial eID, mat a#P{ [ y/Q,[Uzk\ mat.Nd = nlens OQsF$%* SetModelMaterial eID, mat AkV8}>G?#A Print "Set lens index of refraction = " & nlens KrD?Z2x N1z:9=(I '************************************************************************* <o_(,,P% 'Pupil diameter f.u+({"ql '************************************************************************* ^WIGd"^ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) dmE.yVI"O f!##R-A 'Adjust pupil diameter (trimming volume inner hole) " [K>faV oOy_2fwZPp SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" o[K,( Jg%jmI;Y ' Adjust pupil location to just in front of the lens Q>>II|~;J parID = FindFullName( "Geometry.Arizona Eye" ) VH$hQPP5d eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) >[gNQJ6 count = 0 xw&N[y5 While GetOperationCount(eID)>count !qVnziE,, GetOperation eID, count, op 2t"&>1 If op.Type="ShiftZ" Then *`wgqin DeleteOperation eID,count y[sO0u\ count=count-1 i;}mIsNBY End If \TXCq@ count=count+1 #x5?RHX56 Wend qCgoB 0 op.Type = "ShiftZ" 97L#3L6t op.val1 = taq-0.01 +HNM$yp op.parent = parID H~r":A'"* AddOperation eID, op "iTi+UZxe JQ]A"xTIa* Print "Set pupil diameter = " & pupilDiam &>%9JXU Eh&HN-& 'Update AZ Eye subassembly Description yMbg1+:
eID = FindFullName( "Geometry.Arizona Eye" ) XhG3Of-6 GetEntity eID, entity $[DSe~ entity.Description = "Accommodation = " & A & "D" )wueR5P SetEntity eID, entity T:(c/> eww/tG a Update _mn2bc9M Print "DONE!" Z`Sbq{Kx X[KHI1@w End Sub w [7vxQ!- &i?>mt 如果屈光度是4,光瞳直径是4,则会输出如下数据: x 2Cp{+} %T'<vw0 Accommodation = 4 Diopters eJwHeG Pupil Diameter = 4 mm DDwm;,eZ Set aqueous humor thickness = 2.81 VgyY7INx9 Set anterior lens radius = 10.4 and conic constant = -2.375869 ]:r6 Set posterior lens radius = -4.424557 and conic constant = -3.081019 ]KE"|}B Set lens thickness = 3.927 M|xs>+r* Set lens index of refraction = 1.42672 MGE8S$Z Set pupil diameter = 4 _/`H<@B_U DONE! E|v9khN(].
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