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简介 }sU\6~ GXRjR\Ch 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。 ;Z_C3/b [s2V-'2 模型 9-^p23.@[j @7=D ]yu 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。 M::iU_ 1#<E]<='t Table 1. AZ眼睛模型的定义 h;KK6*Z*$E 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. pQ Y> #U}U>4' 光源 uLM_KZ RX1{?*r]Z 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。 Snu;5:R }A7qIys$4 A%1=6 图1. 光源和提示信息使用 U08?*{ 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 @RIEO%S YMTA`T(+ 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 NR&9:? =.hDf<U 图2. 字母F光源的设定方法光 61/zrMPn uFWgq::\ 图3. 字母F在视网膜上位置点列图 %},G(> 视网膜的散射 k#JG N{t:%[ 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 @t8kN6. ] <3?=$ q'U5QyuC 图4. 视网膜朗伯散射设定 b
H_pNx81 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。 8M9\<k6 IJY5wP1" *v ^"4 图5. 视网膜重点采样规格设定 \]A;EwC4C 脚本 @a\SR'8 b6vYM_ Q 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: pHB35=p28 je4&'vyU 图6. 用户对话框的创建与编辑 f<:U"E. 图7. 用户对话框编辑器 78CJ 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。 Gc!8v}[7J 余下的脚本计算与屈光度有关的所有参数。 BQ&q<6Tk ~<-
ci 分析 dMmka $3.vVnc 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 H#6^-6;/ hO.G'q$V 图7. 字母F在视网膜上颜色分析 F}(QKO* 脚本代码 G=HxD4l n qLAby_ Option Explicit 'Remove this to enable non-dimensioned variables to be used. [Cqqjv;_ -wQ^oOJ Dim entity As T_ENTITY #S%Y;ilq Dim op As T_OPERATION `uZv9I" Dim mat As T_MODELMATERIAL +`zi>= Dim A As Double 9m!! b{ Dim pupilDiam As Double ;c-
]bhBB Dim eID As Long Z#6~N/b Dim parID As Long r`R~{;oT Dim count As Integer &^n>ZY, Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double M:Y*Tb6w Dim tlens As Double, nlens As Double PT#eXS9_ Dim curv As Double, conic As Double &s^>S?L- Dim ok As Long 04PoBv~g #;LMtDaL Sub Main Cz@FZb8 /;NE]{K '用户输入对话框 3zTE4pHzu+ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Yuo1'gE+ TextBox 220,21,40,21,.TextBox1 'default: 0 `X<`j6zaG Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 :{b6M/ OKButton 40,91,90,21 Sci4EGc CancelButton 190,91,90,21 gO:Z6}3vM Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Bf:tal6 -M TextBox 220,49,40,21,.TextBox2 'default: 4 g"]<J& End Dialog lIVxW+ Dim dlg As UserDialog ,+/9K)X $FQcDo|[ ok = Dialog (dlg) HKiVEg _TOi
[GT If ok=0 Then 'cancel button was pressed 5+bFy.UW Print "Execution cancelled." ?S@R~y0K End S -6"f/ End If <F)w=_%& )y`TymM[F 'Assign accommodation and pupil diameter & use defaults if field left empty dT]L-uRZgy If dlg.TextBox1 = "" Then +t>*l>[ A = 0 'Default accommodation <,@H;|mZ Else <DXmZ1 A = CDbl(dlg.TextBox1) "VDk1YX_&l End If 1]>$5 1Q [T 4 pgt'H If dlg.TextBox2 = "" Then L8:]`MQ0 pupilDiam = 4 'Default pupil diameter 0Q$~k Else V9zywM pupilDiam = CDbl(dlg.TextBox2) 2~M;L&9- End If ]M~8@K mNx,L+3 Print " " }0BL0N`_ Print "Accommodation = " & A & " Diopters" G}P)vfcH Print "Pupil Diameter = " & pupilDiam & " mm" JN&MyA" C!7U<rI ' Calculate new parameters with accommodation 0):uF_t< taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness TZh\#dp4l TwM1M["3 Rant = 12.0 - 0.4*A 'Radius of anterior lens X:G&5 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 7MO U~{Sa+ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens .'5'0lR5 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens l5=u3r9WYC O1?B{F/ e tlens = 3.767 + 0.04*A 'Lens thickness }c`
?0FQ e(}oq"'z nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction (|g").L C~ZE95g 'Adjust parameters to account for accommodation VLh%XoQx[ t7|MkX1 '************************************************************************* 9 m\)\/V 'Aqueous thickness (Position of Lens) |.b%rVu '************************************************************************* 0 W~.WkD eID = FindFullName( "Geometry.Arizona Eye.Lens" ) H\)gE> GetCustomElement eID, entity d[Rb:Yw 20rN,@2< parID = FindFullName( "Geometry.Arizona Eye" ) <G\
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x$ ' Delete any shift(s) in z $zC6(C(l count = 0 x*unye7 While GetOperationCount(eID)>count V.;:u#{@-Q GetOperation eID, count, op /:#j?c If op.Type="ShiftZ" Then _Fy4DVCg DeleteOperation eID,count !Z
U_,[ count=count-1 EvwbhvA( End If E7rX1YdR count=count+1 [#7y[<.P Wend i^je.,Bi [urH a 'Set new shift in 3AvVU]@&Z@ op.Type = "ShiftZ" 4-y6MH op.val1 = taq d@-wi%,^ op.parent = parID 4JGE2ArR AddOperation eID, op m9#}X_&x Print "Set aqueous humor thickness = " & taq-0.55 nHSTeFI? ]@*tfz\YaH '************************************************************************* TT|-aS0l(u 'Radius and conic constant of anterior lens w`M]0'zls '************************************************************************* >W8bWQ^fK eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) )*!1bgXQ GetConic eID, entity, curv, conic *I=_*LoG2 4$%`Qh>yA SetConic eID, entity, 1/Rant, CCant ewo*7j4* Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant %v]7BV^%6 pAENXC\, '************************************************************************* U8YO0}_z 'Radius and conic constant of posterior lens /r-8T>m '************************************************************************* v-ThdE$G# eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 9U]pH%.9 GetConic eID, entity, curv, conic a|UqeNI{ wOjv[@d SetConic eID, entity, 1/Rpost, CCpost !loO%3_) Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost e:qo_eSC^- w]n4KR4 '************************************************************************* *7\W=- 'Lens thickness (Position of posterior lens surface) e d_m +NM '************************************************************************* /a%*u6z@ *0O<bm parID = FindFullName( "Geometry.Arizona Eye.Lens" ) WI6(#8^p =w6}\ 'X ' Delete any z-shift(s) q=njKC count = 0 au}s=ua~i While GetOperationCount(eID)>count u-kZW1wrQ GetOperation eID, count, op 7g5@vYS+ If op.Type="ShiftZ" Then {(%~i37 DeleteOperation eID,count ( :iPm< count=count-1 <z',]hy End If -rO*7HO count=count+1 I
:@|^PYw Wend bGu([VB !f`5B( @ 'Set new z-shift w?_`/oqd| op.Type = "ShiftZ" SAy{YOLtl op.val1 = tlens W]zwghxH op.parent = parID 4j^bpfb, AddOperation eID, op N2T&,&,t Print "Set lens thickness = " & tlens J]dW1boT@ /w0w*nH '************************************************************************* [T-*/}4$ 'Lens index of refraction gn^!"MN+g '************************************************************************* -8/ JP
eID = FindMaterial( "Lens" ) k&!6fZ) GetModelMaterial eID, mat [EER4@_ SetX#e?q~ mat.Nd = nlens D&-vq,c SetModelMaterial eID, mat Tv1]v. Print "Set lens index of refraction = " & nlens $C$ub&D
~" R1Yqz $# '************************************************************************* %7 /,m 'Pupil diameter B>, A(X& '************************************************************************* q=+wI"[ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) jI A#!4 2
ZK%)vq0 'Adjust pupil diameter (trimming volume inner hole) Mb1wYh ??j&i6sp SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" @%:E } Ok,HD7 ' Adjust pupil location to just in front of the lens s*.3ZS5 parID = FindFullName( "Geometry.Arizona Eye" ) I3PQdAs~&h eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) FllX za) count = 0 Zt_r9xs> While GetOperationCount(eID)>count :T5A84/C GetOperation eID, count, op y]
y9'5_ If op.Type="ShiftZ" Then bJPJ.+G7 DeleteOperation eID,count T6X}Ws " count=count-1 ']h
IfOD"r End If ;t!9]1 count=count+1 !vVT]k[N Wend u-:MVEm op.Type = "ShiftZ" ly=a>}F_ op.val1 = taq-0.01 #"<?_fao~ op.parent = parID E<k^S{ AddOperation eID, op zIm-X,~I$ _ ~[M+IO
Print "Set pupil diameter = " & pupilDiam D7gHE Z vRxi&Z{? 'Update AZ Eye subassembly Description W "k|K: eID = FindFullName( "Geometry.Arizona Eye" ) C99&L3bz^( GetEntity eID, entity DN<M?u] entity.Description = "Accommodation = " & A & "D" x;(g SetEntity eID, entity 6bUl>4 kP?_kMOx Update fbV@= (y? Print "DONE!" }/"4|U x)5LT}p End Sub 7f
r>ZY^ c 6q/X* 如果屈光度是4,光瞳直径是4,则会输出如下数据: }uiPvO+&p `O
n(v Accommodation = 4 Diopters =Epq%,4nG Pupil Diameter = 4 mm d' OGVN Set aqueous humor thickness = 2.81 &`@lB (m Set anterior lens radius = 10.4 and conic constant = -2.375869 A%n?} Set posterior lens radius = -4.424557 and conic constant = -3.081019 d- kZt@DL= Set lens thickness = 3.927 lQ$+JX;n(y Set lens index of refraction = 1.42672 | k}e&Q_/G Set pupil diameter = 4 ?Sw /(}|m DONE! !5~k:1= 7>mhK7l #j.FJFGX QQ:2987619807 ayeCi8
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