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简介 ?+}_1x` 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。 :E )>\& RdRp.pb8 模型 *wB1,U{ %/ #NK1&M 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。 p4
^yVa ExL0?FemWV Table 1. AZ眼睛模型的定义 Cd}<a?m, 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. 'kO!^6=4M lchPpm9 光源 IKilr' P:MT*ra*, 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。 ={@6{-tl V{3x!+q |imM#wF 图1. 光源和提示信息使用 KF!Yf\ 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。 ,M
^<CJ PP33i@G 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。 R|87%&6'] jkF^-Up. 图2. 字母F光源的设定方法光 Wf>R&o6tr :emiQ 图3. 字母F在视网膜上位置点列图 o9yJf#-En 视网膜的散射 nazZ*lC 5IjGm 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。 3eAX.z`D 0rs"o-s< l L@XM2" 图4. 视网膜朗伯散射设定 gu.}M:u 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。 qHlQ+:n 9w"4K. <
!C)x 图5. 视网膜重点采样规格设定 m'=Crei 脚本 nV/G8SeI `%"\@< 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: j@3Q;F0ba X[BIA+6 图6. 用户对话框的创建与编辑 TpwkD_fg 图7. 用户对话框编辑器 oDA XiY$u 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。 FxWS V| Z 余下的脚本计算与屈光度有关的所有参数。 3<f}nfB%r? 2*l/3VW 分析 h_3E)jc M; tqp8 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 3J|F?M"N7 Q6!zZ))~ 图7. 字母F在视网膜上颜色分析 _FU_Ubkr 脚本代码 SBk4_J/_ Z4w!p?Wqa Option Explicit 'Remove this to enable non-dimensioned variables to be used. ,pQZ@I\z $2M$?4S/T Dim entity As T_ENTITY N gGp Dim op As T_OPERATION BLf>_bUk Dim mat As T_MODELMATERIAL '9Xu
p Dim A As Double Hc$O{]sq Dim pupilDiam As Double -4IE]'## Dim eID As Long rCbDu&k] Dim parID As Long jTtu0Q| Dim count As Integer ;LPfXpR Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double b)5uf'?- Dim tlens As Double, nlens As Double 0#s"e}@v Dim curv As Double, conic As Double aU "8{ Dim ok As Long IT7wT+ yT"Eq"7/Y# Sub Main Val|n*% /}fHt^2H '用户输入对话框 (!7sE9rP Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 2M#Q.F TextBox 220,21,40,21,.TextBox1 'default: 0 GxI!{oi2 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 y@: h4u"3 OKButton 40,91,90,21 ^?7-r6 CancelButton 190,91,90,21 CR`Q#Yi Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ):6 8%, TextBox 220,49,40,21,.TextBox2 'default: 4 Q4!_>YZ End Dialog b"uu Dim dlg As UserDialog 0$)>D== IS{wtuA. ok = Dialog (dlg) WwBOM~/`2 p{Yv3dNl If ok=0 Then 'cancel button was pressed FaQe_; Print "Execution cancelled." 2W96Zju\ End p;59? End If oim9<_ sV{,S>s 'Assign accommodation and pupil diameter & use defaults if field left empty Bs_s&a> If dlg.TextBox1 = "" Then j_!F*yul A = 0 'Default accommodation 7uS~MW Else .
y-D16V A = CDbl(dlg.TextBox1) ~ Ei $nV End If o WrKM XSe=sHEI If dlg.TextBox2 = "" Then h-#6av: pupilDiam = 4 'Default pupil diameter qo90t{|c Else mPtZO*Fc pupilDiam = CDbl(dlg.TextBox2) Q_Q''j(r6b End If hk(ZM#Bh Pmr5S4Ka Print " " @uqd.Q Print "Accommodation = " & A & " Diopters" I {S;L Print "Pupil Diameter = " & pupilDiam & " mm" fcRxp{*zO 3LJ+v5T~ ' Calculate new parameters with accommodation j^j1 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness qPX~@^`9 e#L8X
{f Rant = 12.0 - 0.4*A 'Radius of anterior lens q#Z@+(^ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens w(*vj yYIf5S`V] Rpost = -5.224557 + 0.2*A 'Radius of posterior lens #zv3b[@ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 2\A$6N;_ JgKO|VO tlens = 3.767 + 0.04*A 'Lens thickness -LoZs
ru RE7?KR> nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction uB]7G0g: ~:rl=o } 'Adjust parameters to account for accommodation 25nt14Y0u jiV<+T? '************************************************************************* :j9l"5" 'Aqueous thickness (Position of Lens) n71r_S* '************************************************************************* Xk~D$~4< eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ?mwt~_s9 GetCustomElement eID, entity w=0(<s2 ~9a<0Mc? parID = FindFullName( "Geometry.Arizona Eye" ) v}}F,c(f Uu10)/.LC ' Delete any shift(s) in z \+oQd=K@ count = 0
acajHs While GetOperationCount(eID)>count ExY] Sdx GetOperation eID, count, op GfxZ'VIn If op.Type="ShiftZ" Then 9|^2",V DeleteOperation eID,count <.x{|p count=count-1 fy>{QC\ End If . oF
&Ff/[ count=count+1 e8>}) Wend %~O,zs.2p !_]Y~[ 'Set new shift in 9Z@hPX3. op.Type = "ShiftZ" :;RMo2Tl op.val1 = taq @wGPqg op.parent = parID LiC*@W AddOperation eID, op |IeTqEu9 Print "Set aqueous humor thickness = " & taq-0.55 \#2Z)Kz m4[ ;(1 '************************************************************************* OZb-:!m* 'Radius and conic constant of anterior lens .wEd"A&j '************************************************************************* uanhr)Ys eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) !hA-_ GetConic eID, entity, curv, conic & TCkpS 1jmjg~W SetConic eID, entity, 1/Rant, CCant =J]&c?I Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant DTX0 WA<v9#m '************************************************************************* ?(@
7r_j 'Radius and conic constant of posterior lens G*?8MTP8![ '************************************************************************* mxvp3t \ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 8 `v-<J GetConic eID, entity, curv, conic `[y^ :mj !4ocZmj\ SetConic eID, entity, 1/Rpost, CCpost aj-Km`5r} Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost l]
K3Y\#bP j"8ZM{aO '************************************************************************* $f$SNx)), 'Lens thickness (Position of posterior lens surface) gT6z9 '************************************************************************* @f_Lp%K BwN0!lsF3 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) CQc+#nRe WJ]T\DI ' Delete any z-shift(s) :p1u(hflS count = 0 %HhBt5w While GetOperationCount(eID)>count 0gu_yg! R GetOperation eID, count, op s-NX o If op.Type="ShiftZ" Then >1X|^ DeleteOperation eID,count Gf%~{@7=u count=count-1 6lZ3tdyNo End If 1>.Ev,X+e count=count+1 WSPI|#Xr% Wend zF@/K` _f7 9wx\B 'Set new z-shift "-E\[@/ op.Type = "ShiftZ" =?5]()'*n op.val1 = tlens h!,v/7= op.parent = parID FBG4pb9=~ AddOperation eID, op b35fs]}u-6 Print "Set lens thickness = " & tlens Qry@
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>^O7 '************************************************************************* 8 %:Iv(UMk 'Lens index of refraction `](e:be} '************************************************************************* m%0p\Y-/ eID = FindMaterial( "Lens" ) Q@= Q0 GetModelMaterial eID, mat Mg+2.
8% YByLoM* mat.Nd = nlens .w:DFk^E]b SetModelMaterial eID, mat 6u?>M9 Print "Set lens index of refraction = " & nlens ),_@WW;k S0$8@"~= '************************************************************************* GWGSd\z 'Pupil diameter "BAK !N$9 '************************************************************************* Oz.HH eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) eB2a-, (xycJ`N 'Adjust pupil diameter (trimming volume inner hole) //B&k`u 6]i-E>p3R SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Q(G#W+r }ZYd4h|g\z ' Adjust pupil location to just in front of the lens @ 8(q$ parID = FindFullName( "Geometry.Arizona Eye" ) -+-?w|}qV eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) @?ebuj5{e count = 0 zE*li`@ While GetOperationCount(eID)>count \Zk;ikEY GetOperation eID, count, op C-xr"]#] If op.Type="ShiftZ" Then *9
{PEx DeleteOperation eID,count O}gV`q; count=count-1 5; C| End If ]dVGUG8 count=count+1 t6rRU~;} Wend Fk7?xc op.Type = "ShiftZ" 39c2pV[ op.val1 = taq-0.01 H;mSkRD3N op.parent = parID Y+pHd\$-4 AddOperation eID, op I]|Pq /*~EO{o Print "Set pupil diameter = " & pupilDiam Brw@g8w-X RIR\']WN 'Update AZ Eye subassembly Description ?9vuuIE eID = FindFullName( "Geometry.Arizona Eye" ) a"1t-x GetEntity eID, entity NCXRevE entity.Description = "Accommodation = " & A & "D" wKh4|Ka SetEntity eID, entity i%iL[id:w LG0;#3YwH Update E#34Wh2z Print "DONE!" gE'sOT9v lM`2sy End Sub /A\8 mL8 Ha#=(9. 如果屈光度是4,光瞳直径是4,则会输出如下数据: >fG3K` UsG~row:! Accommodation = 4 Diopters @)F )S7 Pupil Diameter = 4 mm KRbvj Set aqueous humor thickness = 2.81 Xfc-UP|} Set anterior lens radius = 10.4 and conic constant = -2.375869 `?H]h"{7Q Set posterior lens radius = -4.424557 and conic constant = -3.081019 2y\E[j A Set lens thickness = 3.927 d7^}tM Set lens index of refraction = 1.42672 r wL`Czs Set pupil diameter = 4 'ycJMYP8 DONE! [|wZ77\ ';Ea?ID (文章来源:讯技光电)
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