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简介 H,3\0BKk *a;@* 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。 'rp }G&m }o4N<%/+ 模型 Q_-_^J \>LnLH( 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。 eV:9y IJYL s
Table 1. AZ眼睛模型的定义 g9D^) V 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. 6tHO!`}1 fZ04!R 光源 ryF7 )a9 ]US^ 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。 9EDfd NN g8qgk:} wN1niR' 图1. 光源和提示信息使用 &qpr*17T 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。 ]D[DU]K !tfb*@{;' 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。 0"2=n.## 'o|30LzYgQ 图2. 字母F光源的设定方法光 L^2FQti> r.3/F[. 图3. 字母F在视网膜上位置点列图 L
pR''`2BT 视网膜的散射 S}APQ ]8q3> 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。 eSWLrryY eP*lI<NQ1 p' M%XBu 图4. 视网膜朗伯散射设定 d
;vT ~; 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。 i1H\#;`$ ~\{^%~[48 |
N0Z-| 图5. 视网膜重点采样规格设定 -~?J+o+Pr" 脚本 hxCvk/7sT "Rn3lj0 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: pw7[y^[Qg 'F>'(XWWQ 图6. 用户对话框的创建与编辑 qM#R0ZUIe\ 图7. 用户对话框编辑器 tOfg?)h{dc 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。 O@p]KSfk 余下的脚本计算与屈光度有关的所有参数。 /|xra8?H[ 0-~\
W( 分析 D8
hr?:I9 bh^LIU 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ^i:`ZfA# 1V8-^ 图7. 字母F在视网膜上颜色分析 EwOV;>@T? 脚本代码 K~@Mg1R iD<(b`S Option Explicit 'Remove this to enable non-dimensioned variables to be used. +$oF]OO &f&z_WU Dim entity As T_ENTITY p.LFVFPT Dim op As T_OPERATION @|Rrf*J?% Dim mat As T_MODELMATERIAL MEwo}=B Dim A As Double #1>X58I^ Dim pupilDiam As Double m1Y>Nj[f Dim eID As Long V}\~ugN)y Dim parID As Long 8Y5 Dim count As Integer !
u:Weoz Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double <=f}8a.R3 Dim tlens As Double, nlens As Double FJ asS8 Dim curv As Double, conic As Double .A6(D$O k Dim ok As Long lo[.&GD YW{C} NA Sub Main hWX% 66 xQUu|gtL4 '用户输入对话框 tKpmm`2 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 s`0QA!G{- TextBox 220,21,40,21,.TextBox1 'default: 0 kT;S4B Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 S#+h$UVh OKButton 40,91,90,21 {GC?SaK CancelButton 190,91,90,21 3YVi"
k?2 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 2Lx3=[ik TextBox 220,49,40,21,.TextBox2 'default: 4 :_O%/k1\@ End Dialog 'Fmvu Dim dlg As UserDialog Yb E-6|cz ^<e.]F25M ok = Dialog (dlg) tg{H9tU; Hla0 5N' 4 If ok=0 Then 'cancel button was pressed y\a1iy Print "Execution cancelled." xD6@Qk End b#X^=n2 End If o
LvZ B>2tZZko 'Assign accommodation and pupil diameter & use defaults if field left empty Z?\2F% If dlg.TextBox1 = "" Then '#k0a,<N A = 0 'Default accommodation ONe# rKJ_ Else %"P,1&\^ A = CDbl(dlg.TextBox1) #FNcF>3> End If ?]*^xL;x? 78/Zk}I] If dlg.TextBox2 = "" Then uuQ(& pupilDiam = 4 'Default pupil diameter ~J P=T Else m@^1JlH pupilDiam = CDbl(dlg.TextBox2) qTqwPWW* End If L31HGH2l ]wtb-PC Print " " p>upA)W] Print "Accommodation = " & A & " Diopters" 3? HhG Print "Pupil Diameter = " & pupilDiam & " mm" Vv ?-"\Z> <TP=oq?I/ ' Calculate new parameters with accommodation V>b\[(=s taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 5=Di<! a; ~P@Q7T* Rant = 12.0 - 0.4*A 'Radius of anterior lens
Z
/9> CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens u,UmrR S;)w. Rpost = -5.224557 + 0.2*A 'Radius of posterior lens |>#{[wko CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens
~/P&Tub^ |cR;{Z8?_ tlens = 3.767 + 0.04*A 'Lens thickness F F|FU< *m#Za<_Gv nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction }nL7T'$> 8p: j&F 'Adjust parameters to account for accommodation @w?P7P<O` PF53mUs4 '************************************************************************* .dav8n* 'Aqueous thickness (Position of Lens) Dp':oJC '************************************************************************* R.yC(r eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 43@{JK9G GetCustomElement eID, entity 2'W<h)m)z aXoVy&x= parID = FindFullName( "Geometry.Arizona Eye" ) 7eiV{ tYF 7D;cw\ | ' Delete any shift(s) in z Gy6l<:; count = 0 tfGHea)M While GetOperationCount(eID)>count OEkN(wF GetOperation eID, count, op @g&ct>@y If op.Type="ShiftZ" Then ;9c<K DeleteOperation eID,count +>r/ 0b count=count-1 +w+}b^4 End If {PVW D7 count=count+1 m+Rv+_R Wend LL3#5AA"k| IkGfnXJ 'Set new shift in "\3B^ e, op.Type = "ShiftZ" e8GEoD op.val1 = taq 5.MGaU^Z$ op.parent = parID zc;|fHW~O AddOperation eID, op )s%[T-uKi Print "Set aqueous humor thickness = " & taq-0.55 TL}++e
7+ iT%} $Lu~ '************************************************************************* p{j.KI s7 'Radius and conic constant of anterior lens %'X[^W '************************************************************************* PEc=\? eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) j'HZ\_ GetConic eID, entity, curv, conic -}KC=,]vh FW21 U< SetConic eID, entity, 1/Rant, CCant [rSR:V?"a Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant
.p e( lP `0Oh_8" '************************************************************************* yge,8i)c 'Radius and conic constant of posterior lens !0vG|C;' '************************************************************************* *tK\R&4,4s eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) '2[albxSc GetConic eID, entity, curv, conic A}3=561F?5 `1bv@yzq SetConic eID, entity, 1/Rpost, CCpost Ndi9FD3im Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost !Ikt '5/ x3o]U)^ '************************************************************************* ' <@3i[M 'Lens thickness (Position of posterior lens surface) /(.mp<s0 '************************************************************************* /assq+H CD~z=vlK- parID = FindFullName( "Geometry.Arizona Eye.Lens" ) a- |*?{o yrC7F`. ' Delete any z-shift(s) gk0( ANx count = 0 "HDcmIXg& While GetOperationCount(eID)>count @Bf%s(Uj+ GetOperation eID, count, op v5QqS8u_C If op.Type="ShiftZ" Then
?B}{GL2) DeleteOperation eID,count q)^Jj?W count=count-1 PqiB\~o@Z End If f7X6fr< count=count+1 qa0 yg8,< Wend Yd#/1!A7u =9fajRFTt 'Set new z-shift JNJ=e,O, op.Type = "ShiftZ" k[:bQ)H op.val1 = tlens 6{^E{go op.parent = parID *fn*h[pV& AddOperation eID, op 9*{[buZX Print "Set lens thickness = " & tlens 9mmCp&~Z X ><?F|#7T '************************************************************************* rjp-Fw~1w 'Lens index of refraction d;>#Sxf '************************************************************************* `CgaS# eID = FindMaterial( "Lens" ) rU2%dkTa GetModelMaterial eID, mat :[hgxJu+ {6_|/KE9_ mat.Nd = nlens NqDHCI SetModelMaterial eID, mat ?C&z]f3(: Print "Set lens index of refraction = " & nlens oaoU _V 'i4_`^:+ '************************************************************************* w[IE 'Pupil diameter S&b*rA02zp '************************************************************************* #nK>Z[ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) %\H|B0 ](wvu(y\E 'Adjust pupil diameter (trimming volume inner hole) /p+>NZ"b &iA?+kV SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" |Y [wzDYV Od5JG .] ' Adjust pupil location to just in front of the lens =p=rg$? parID = FindFullName( "Geometry.Arizona Eye" ) /qy-qUh3h eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) @EnuJe count = 0 .7.b:Dn0 While GetOperationCount(eID)>count .MJofE;Jn GetOperation eID, count, op -wSg2'b4E If op.Type="ShiftZ" Then /iJ4{p DeleteOperation eID,count /$'AjIg4:& count=count-1 3P^sM1 End If oIb|*gX^ count=count+1 TTt#a6eJ Wend 49dd5ddr op.Type = "ShiftZ" pm_u
op.val1 = taq-0.01 Dm-zMCf}Q op.parent = parID #>mr[ AddOperation eID, op Ct=-4 79xx2 Print "Set pupil diameter = " & pupilDiam jkt_5+S f'VX Y- 'Update AZ Eye subassembly Description f=mZu1(FZ eID = FindFullName( "Geometry.Arizona Eye" ) I.94v
#r GetEntity eID, entity ]A<~XIu entity.Description = "Accommodation = " & A & "D" 6T#+V37 SetEntity eID, entity )XzI
#iQ h9Y%{v Update zN:K%AiGxe Print "DONE!" P)MDPI+~ ZsOIH< |