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V5g, u(s/4Lu 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。 07_ym\N &l=%*`On 模型 !P &F6ViO= p(F}[bP 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。 wf<=rW' Z/wKUK; Table 1. AZ眼睛模型的定义 K;u<-?En 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. %Hk9.1hn5 HCI|6{k 光源 G Uf[Dz lKd+,< 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。 X&[S.$_U E2s
lpo DUk&`BSJ 图1. 光源和提示信息使用 Dg$Z5`%k8 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。 `;ofQz4 q}PeXXH 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。 TRl,L5wd-? A?V[/ 图2. 字母F光源的设定方法光 `N_elf://n Nd.+Rs 图3. 字母F在视网膜上位置点列图 .X;zEyd 视网膜的散射 3Ms`
ajJ kgX"LQh;[G 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。 *Op;].>E (3DjFT3
w Zr0bVe+h 图4. 视网膜朗伯散射设定 RnN]m!"5 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。 3iHUG^sLW y\DR,$Py +0016UgS# 图5. 视网膜重点采样规格设定 bqHR~4 #IR 脚本 BULf@8~( (5s$vcK 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: 0^41dfdE 2nW:|*:/p6 图6. 用户对话框的创建与编辑 lLO|, 图7. 用户对话框编辑器 H uPw?8w= 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~(s3pSCo 余下的脚本计算与屈光度有关的所有参数。 .5ap9li] *{qW7x.6h 分析 YRXXutm uT'}_2=: 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 g-0?8q5T6 Wj"\nT4 图7. 字母F在视网膜上颜色分析 ^t&S?_DSZ 脚本代码 R36BvW0X "+oP((9 Option Explicit 'Remove this to enable non-dimensioned variables to be used. )[d?&GK l^ P[nQDH Dim entity As T_ENTITY ,m| :U Dim op As T_OPERATION ~c&ygL3 Dim mat As T_MODELMATERIAL ^gb3DNV~y Dim A As Double vUEG0{8l Dim pupilDiam As Double :Ve>tZeW Dim eID As Long "~R,%sYb( Dim parID As Long EZy:_xjZ Dim count As Integer sN`2"t/s Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double A>@ i
TI Dim tlens As Double, nlens As Double n[~kcF Dim curv As Double, conic As Double aDrF"j Dim ok As Long c418TjO; dWK;
h Sub Main `SdvXn J9!}8uD '用户输入对话框 OAoTsqj6 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 lSGtbSyDI TextBox 220,21,40,21,.TextBox1 'default: 0 $#3O:aW Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 [{]/9E/& OKButton 40,91,90,21 kD&%
7Vz CancelButton 190,91,90,21 ,$i2vGd Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 S$ u`)BG): TextBox 220,49,40,21,.TextBox2 'default: 4 sw<mmayN End Dialog o~Jce$X Dim dlg As UserDialog KIY/nu
!t. ok = Dialog (dlg) >o=O^:/L pKeK6K\8 If ok=0 Then 'cancel button was pressed [BPK0 Print "Execution cancelled." _[D6WY+
End ( v<l9}! End If 6n[O8^ d']CBoK 'Assign accommodation and pupil diameter & use defaults if field left empty EL*OeyU1l If dlg.TextBox1 = "" Then 7ojU]l y A = 0 'Default accommodation N_3$B= Else F8u;C:^d A = CDbl(dlg.TextBox1) m=g\@&N End If up(6/-/.7 ]i$<<u If dlg.TextBox2 = "" Then >K|<hzZ pupilDiam = 4 'Default pupil diameter s|p,UK Else ( (.b& pupilDiam = CDbl(dlg.TextBox2) /INjP~C End If ]H ze D<V[:~-o Print " " VFmG\ Print "Accommodation = " & A & " Diopters" y
{&"g Print "Pupil Diameter = " & pupilDiam & " mm" 9%{V?r]k I&2)@Zw ' Calculate new parameters with accommodation Uq}F rK} taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness (8JL/S;Z$ "!- Rant = 12.0 - 0.4*A 'Radius of anterior lens ua!i3]18 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ivgV5)". CcGE4BB Rpost = -5.224557 + 0.2*A 'Radius of posterior lens HuVx^y`
@ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens
8 IeE7 tu4-##{ tlens = 3.767 + 0.04*A 'Lens thickness Ox | ? T^z nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Sw1z^` Th\w#%'N 'Adjust parameters to account for accommodation h>w(Th\H r6JQRSakR '************************************************************************* Yz%A Kp 'Aqueous thickness (Position of Lens) ~J~@mE2ks '************************************************************************* *Z9Rl> eID = FindFullName( "Geometry.Arizona Eye.Lens" ) U z*7J GetCustomElement eID, entity <\44%M"iC- AVn?86ri parID = FindFullName( "Geometry.Arizona Eye" ) 3np |\i 5`_UIYcI ' Delete any shift(s) in z oouhP1py, count = 0 6dH> 0l While GetOperationCount(eID)>count g!QX#_~Il GetOperation eID, count, op [Re.sX}$Y If op.Type="ShiftZ" Then f9%M:cl DeleteOperation eID,count pr=f6~Z-y count=count-1 buj*L& End If zl]Ic' _i count=count+1 c"wk_# Wend O:%,.??<% =<BPoGs5 'Set new shift in E;o
"^[we op.Type = "ShiftZ" zfsGf'U op.val1 = taq w\K(kNd( op.parent = parID
Qhc>,v) AddOperation eID, op 4MFdhJoN Print "Set aqueous humor thickness = " & taq-0.55 |8{c|Qz 3+<f7 '************************************************************************* 9} *Pb6 'Radius and conic constant of anterior lens \kR:GZ`{UV '************************************************************************* >s%&t[r6 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) L*(!P4S%} GetConic eID, entity, curv, conic za,JCI I)(@'^) SetConic eID, entity, 1/Rant, CCant <rKfL`8p Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant a_T3< Fkvf[!Ci '************************************************************************* zObrp 'Radius and conic constant of posterior lens l-gNJ=l+K '************************************************************************* up;^,I eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) CMiE$yC GetConic eID, entity, curv, conic VF bso3q<j F97HFt6{ SetConic eID, entity, 1/Rpost, CCpost U
=i=E}' Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost eZ
G#op /5wIbmz@I '************************************************************************* -V F*h.' 'Lens thickness (Position of posterior lens surface) `9`T,uJe '************************************************************************* N<N uBtkA /)J]m parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2:jWO_V@ &y+)xe:&S ' Delete any z-shift(s) <*3#nA-O>i count = 0 Hp(wR'(g& While GetOperationCount(eID)>count 7L4~yazmK GetOperation eID, count, op
/D>G4PP< If op.Type="ShiftZ" Then '89nyx&W DeleteOperation eID,count V |hr 9 count=count-1 S\S31pYT End If =M ."^X count=count+1 ra|Ku! Wend BCI[jfd 7 4XNdsb 'Set new z-shift [r0`D^*= op.Type = "ShiftZ" h|{DIG3 op.val1 = tlens \Gm\sy op.parent = parID .jv#<"DW AddOperation eID, op m85Hx1!p. Print "Set lens thickness = " & tlens d "%6S*dL c>b{/92% '************************************************************************* IIY3/ 'Lens index of refraction SH5a&OVZhn '************************************************************************* "KKw\i eID = FindMaterial( "Lens" ) w!rw% GetModelMaterial eID, mat .L8g(F(=: 7m.>2U mat.Nd = nlens L(q~% SetModelMaterial eID, mat [;pL15-}4 Print "Set lens index of refraction = " & nlens ^u+#x2$Mg :;URLl0 '************************************************************************* fo_*Uva_ 'Pupil diameter +lhnc{;WJv '************************************************************************* l&_PsnU eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) A(D3wctdr HXb_k1n 'Adjust pupil diameter (trimming volume inner hole) 6=p!`DOd Jy
P$'v~ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 6FFM-9*|[ (b"kN( ' Adjust pupil location to just in front of the lens $6~t|[7:%Y parID = FindFullName( "Geometry.Arizona Eye" ) B&"c:)1
C2 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 5BS !6o;P' count = 0 7qLB 9r While GetOperationCount(eID)>count )ml#2XP!f GetOperation eID, count, op j_0xE;g"] If op.Type="ShiftZ" Then XaH; DeleteOperation eID,count giHqc7-PaX count=count-1 UgTgva>? End If f>[{1M]n\ count=count+1 eL1)_M;{ Wend 5"&=BD~D op.Type = "ShiftZ" |e91KmiqJ op.val1 = taq-0.01 ]VoJ7LoCZ' op.parent = parID cuh Z_l AddOperation eID, op l9naqb:iP zsr; 37 Print "Set pupil diameter = " & pupilDiam 'x u!t'l& "%ZAL\x 'Update AZ Eye subassembly Description |w.h97fj eID = FindFullName( "Geometry.Arizona Eye" ) |4!G@-2V:I GetEntity eID, entity b!T-{Ns6 entity.Description = "Accommodation = " & A & "D" L}VQc9"gc SetEntity eID, entity w"q^8"j! KT0Pmpp5 Update C1x(4&h Print "DONE!" T U^s!Tj <_yy0G End Sub *})Np0k GI%9Tif 如果屈光度是4,光瞳直径是4,则会输出如下数据: qT^0
%O: BeFXC5-qat Accommodation = 4 Diopters _xGC0f ( Pupil Diameter = 4 mm :8U@KABH@h Set aqueous humor thickness = 2.81 xTy)qN]P Set anterior lens radius = 10.4 and conic constant = -2.375869 = ,c!V Set posterior lens radius = -4.424557 and conic constant = -3.081019 )CD-cz6n Set lens thickness = 3.927 {Z}zT1kA Set lens index of refraction = 1.42672 cd;~60@K Set pupil diameter = 4 #:=*n(GT DONE! gp-rTdN
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