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简介 ]6q*)q:` hu&n=6 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。 |lY`9-M`I ]An_5J
模型 x?gQ\0S< cX Ma\#P 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。 f:&)" eq{
[?/ Table 1. AZ眼睛模型的定义 w7r'SCVh3+ 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. C,(j$Id 1j+eD:d' 光源 1NW>wo \UhGGg% 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 c|+y9(0|y i:{:xKiC a AT-0}9z{ 图1. 光源和提示信息使用 j+ I*Xw 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 n~.% p !@A|L#* 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 3#B@83C0Z URk$}_39 图2. 字母F光源的设定方法光 VYHOk3 ~PCTLP~zI 图3. 字母F在视网膜上位置点列图 k,AM]H 视网膜的散射 w gmWo8 A_aO}oBX 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。 \6Xn]S f^~2^p
1te 7WXiG0 图4. 视网膜朗伯散射设定 K[n<+e;G 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。 t6j-?c(' 3mybG%39 vu44 !c@ 图5. 视网膜重点采样规格设定 KLON; 脚本 7bHE!#L`0 nM=2"`@$ 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: xJ$Rs/9C S3nB:$_-; 图6. 用户对话框的创建与编辑 ykJ+%gla 图7. 用户对话框编辑器 <. ezw4ju 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。 mSy|&(l 余下的脚本计算与屈光度有关的所有参数。 n<=y"*
Ca$y819E2 分析 F_K YcPKM@xo 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 )8 oEs :{x!g6bK@ 图7. 字母F在视网膜上颜色分析 $#D
n 4 脚本代码 >xklt"*U, 2-QuT"Gkd Option Explicit 'Remove this to enable non-dimensioned variables to be used. }5QZ6i# tWcizj;?wK Dim entity As T_ENTITY kx:c*3q.k Dim op As T_OPERATION NJ.rv Dim mat As T_MODELMATERIAL o7m99( Dim A As Double l#
}As.o} Dim pupilDiam As Double 2*N&q|ED Dim eID As Long /j`i/Ha1 Dim parID As Long )r-T= Dim count As Integer zw}@nqp Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ~ W2:NQ>i Dim tlens As Double, nlens As Double -$'~;O3s Dim curv As Double, conic As Double oXnC"y}0P Dim ok As Long Iq^~ b5lk0 jA Sub Main SJso'6 g [Od>NO,n+] '用户输入对话框 (xI)"{ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 H( TextBox 220,21,40,21,.TextBox1 'default: 0 8XLxT(YFIs Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Ry3+/] OKButton 40,91,90,21 r)) $XM CancelButton 190,91,90,21 A@9U;8k Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 |Ba4 G` TextBox 220,49,40,21,.TextBox2 'default: 4 !l sy&6 End Dialog Z'7 c^c7_ Dim dlg As UserDialog |!?2OTY tI/mE[W ok = Dialog (dlg) 2U-#0,ll] Zm"!E6`69 If ok=0 Then 'cancel button was pressed GN"M:L^k` Print "Execution cancelled." )^*9oqQ End .6lY*LI End If L,s|gtv z^gDbXS 'Assign accommodation and pupil diameter & use defaults if field left empty (mD-FR@# If dlg.TextBox1 = "" Then ">0/>>Ry A = 0 'Default accommodation ,mAB)at Else GC5#1+fQ A = CDbl(dlg.TextBox1) eXskwV+7 End If \'\N"g`Fr Y yQf If dlg.TextBox2 = "" Then 7I2a*4} pupilDiam = 4 'Default pupil diameter /K2.V@T Else PCV58n3 pupilDiam = CDbl(dlg.TextBox2) .{'Uvn End If 6xDl=*&% )A>U<n $h Print " " v*C+U$_3\1 Print "Accommodation = " & A & " Diopters" *:fw6mnJ# Print "Pupil Diameter = " & pupilDiam & " mm" ~pX(w!^ }J'5EAp ' Calculate new parameters with accommodation 1j${,>4tQ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness V7KtbL# Mipm&5R Rant = 12.0 - 0.4*A 'Radius of anterior lens tk3<sr"IQ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens h%CEb< 9H
!B) Rpost = -5.224557 + 0.2*A 'Radius of posterior lens _{2Fx[m% CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens L.I}-n <{-(\>f!9 tlens = 3.767 + 0.04*A 'Lens thickness b]tA2~e 5'{qEZs^QU nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 1?e>x91 >[E|p6jgT 'Adjust parameters to account for accommodation \>aa8LOe <'o 'H '************************************************************************* 3[|:sa8?s 'Aqueous thickness (Position of Lens) N%n1>!X)! '************************************************************************* ..Uw8u/ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) \@
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GetCustomElement eID, entity $Z(g=nS> &bS"N)je parID = FindFullName( "Geometry.Arizona Eye" ) BRSgB-Rr7 |)!k@?_ ' Delete any shift(s) in z 0$F _hZU count = 0 k_En_\c?p2 While GetOperationCount(eID)>count {'=Nb
5F GetOperation eID, count, op Z+`{JE# If op.Type="ShiftZ" Then [#P`_hx DeleteOperation eID,count jr#g>7yM count=count-1 #<WyId( End If Jegx[*O>b count=count+1 K,L> Wend 5.C[)`_ Ck/_UY| 'Set new shift in |/T<]+X; op.Type = "ShiftZ" @dT: 1s op.val1 = taq H[_uVv;}6 op.parent = parID s:m<(8WRw AddOperation eID, op {Y@-*pL] Print "Set aqueous humor thickness = " & taq-0.55 ^]sMy7X0IK kb}]sj '************************************************************************* nX.s h 'Radius and conic constant of anterior lens 4MF}FS2) '************************************************************************* ^b `>/> eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) VT.{[Kl GetConic eID, entity, curv, conic $jm>tW&; (&Tb,H)= SetConic eID, entity, 1/Rant, CCant HA3SQ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ad3z]dUZ9 .'NO~ '************************************************************************* l~Wk07r3 'Radius and conic constant of posterior lens bh;b`
5 '************************************************************************* !ovZ>,1 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) }96/:
;:k GetConic eID, entity, curv, conic SFk11 .5[LQR SetConic eID, entity, 1/Rpost, CCpost ,TfI Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Y4~wNs6 yY@s(: '************************************************************************* ,d [b"]Zy 'Lens thickness (Position of posterior lens surface) /YugQ.>| l '************************************************************************* , C@hTOT 3EW f|6RI parID = FindFullName( "Geometry.Arizona Eye.Lens" ) A2O_pbQti Zxxy1Fl#.[ ' Delete any z-shift(s) Eztz~oFo count = 0 ZNH*[[Pf While GetOperationCount(eID)>count 5 dNf$a0E GetOperation eID, count, op ]x(2}h^S If op.Type="ShiftZ" Then m9<[bEO<$ DeleteOperation eID,count LG@c)H74 count=count-1 LOb'<R\p End If ga1gd~a count=count+1 l^eNZ3:H Wend eze(>0\f 5t5S{aCDr 'Set new z-shift FnQ_=b
op.Type = "ShiftZ" Q"K >ML>0 op.val1 = tlens /&!d op.parent = parID a^}P_hg}- AddOperation eID, op
Z"%O&O Print "Set lens thickness = " & tlens 1PTu3o&3 ~ew**@N '************************************************************************* >La L!PnZ 'Lens index of refraction Gv+Tg/ '************************************************************************* Q}f}Jf3P eID = FindMaterial( "Lens" ) QB|fFj58u GetModelMaterial eID, mat DGfQo5# qpwh #^2 mat.Nd = nlens acju!,G SetModelMaterial eID, mat IweK!,:>dN Print "Set lens index of refraction = " & nlens Q3O .<9S SnF[mN' '************************************************************************* 674oL, 'Pupil diameter s$\8)V52 '************************************************************************* jUR# eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Qx,$)|_ cxJK>%84 'Adjust pupil diameter (trimming volume inner hole) gWv+i/, \/4%[Q2QDm SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ,JBw$C oY6|h3T=Q$ ' Adjust pupil location to just in front of the lens }:D~yEP parID = FindFullName( "Geometry.Arizona Eye" ) V?J,ab$X# eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) rn5g+%jX* count = 0 ~$ qJw?r
While GetOperationCount(eID)>count N[bf.5T GetOperation eID, count, op -r'seb5 If op.Type="ShiftZ" Then KJJb^6P48W DeleteOperation eID,count XM@i|AK
M0 count=count-1 2GKU9cV*` End If GV@E<dg$R count=count+1 &b6@_C9 Wend xv% USm op.Type = "ShiftZ" dQ|Ht[s= op.val1 = taq-0.01 hSKH#NS op.parent = parID
Z#t)Z " AddOperation eID, op Aag)c~D /\$|D&e
Print "Set pupil diameter = " & pupilDiam IS4K$Ac. v4##(~Tu 'Update AZ Eye subassembly Description wJR i;fvi eID = FindFullName( "Geometry.Arizona Eye" ) N3c)ce7[ GetEntity eID, entity NEou2y+} entity.Description = "Accommodation = " & A & "D" sr@XumT SetEntity eID, entity ]9< 9F ? fX$4TPy(h Update L{,7(C= Print "DONE!" WJ8vHPSM '*;eFnmvs: End Sub 14YV#o: [*ovYpj^ 如果屈光度是4,光瞳直径是4,则会输出如下数据: ,zw=&)W1 $5CY<,f Accommodation = 4 Diopters SWO!E Pupil Diameter = 4 mm y*Q-4_%, Set aqueous humor thickness = 2.81 9.#R?YP$ Set anterior lens radius = 10.4 and conic constant = -2.375869 R/cq00g Set posterior lens radius = -4.424557 and conic constant = -3.081019 (0m$W< Set lens thickness = 3.927 zYF&Dv/u/ Set lens index of refraction = 1.42672 |=}~>!! Set pupil diameter = 4 SA n=9MG DONE! |A/_Qe|s2 ZjW| qb
xWb?i6)z& QQ:2987619807 7:q-NzE\6
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