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简介 NX?6
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s 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。 ro18%'RRI kjOI7` DU 模型 M0woJt[& r9~I R 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。 VaTA|=[; xhncQhf\ Table 1. AZ眼睛模型的定义 c)SQ@B@q 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. OQ4rJ#b 2Kw i4R 光源 /B5rWJ2AS +A2}@k 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。 phy:G}F6% z#+Sf. $A>]lLo0 图1. 光源和提示信息使用 k j&hn 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 }XRRM:B|)( dSbz$Fc 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。 }\vw>iHPX@ pwo @
S" 图2. 字母F光源的设定方法光 W7.QK/@ Wfh+D[^ 图3. 字母F在视网膜上位置点列图 Uk4G9}I 视网膜的散射 aTE;Gy,W v8K4u) 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。 &M2fcw? &Pgk$e%> ?cgb3^R' 图4. 视网膜朗伯散射设定 M[^EHa<i 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 gr4JaV C.+:FY.H l!%V&HJV 图5. 视网膜重点采样规格设定 =_`cY^ib+ 脚本 -@/!u9l 6R!AIOD> 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: ;%O>=m'4 Lg+cHaA 图6. 用户对话框的创建与编辑 qino:_g 图7. 用户对话框编辑器 [.>g.p,; 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 ]?~[!&h 余下的脚本计算与屈光度有关的所有参数。 zO3}c3D~q Ikgia:/-Z 分析 laaoIL^ W+aW2 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 QE`u~ %?!TqJT?{ 图7. 字母F在视网膜上颜色分析 l"9$lF} 脚本代码 )Z63 cr/ 49dN ~k= Option Explicit 'Remove this to enable non-dimensioned variables to be used. '! ~s= _6C,w`[[6 Dim entity As T_ENTITY kj' Dim op As T_OPERATION q #X[oVq Dim mat As T_MODELMATERIAL 0mI4hy Dim A As Double q ?m<9` Dim pupilDiam As Double P@Av/r Dim eID As Long M.KXDD#O Dim parID As Long L$= a,$ Dim count As Integer ?^{Ey[)'( Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double C<N7zM wT Dim tlens As Double, nlens As Double tMr$N[@r Dim curv As Double, conic As Double NucLf6 Dim ok As Long =}[m_rp& z2OXCZ*/ Sub Main Z4tc3e
8PvO_Gz5 '用户输入对话框 K2-nP2Go? Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 );fPir?+ TextBox 220,21,40,21,.TextBox1 'default: 0 j4Y] 8 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1
A}n7A
OKButton 40,91,90,21 Y,d|b V*FH CancelButton 190,91,90,21 o.>Yj)U Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 PsI{y&. TextBox 220,49,40,21,.TextBox2 'default: 4 kI/%|L%6D End Dialog (.~'\@ Dim dlg As UserDialog ~D!Y]
SK 5z9'~Gfb ok = Dialog (dlg) QjyJmW("Z ufS0UD8%H If ok=0 Then 'cancel button was pressed P:c'W? Print "Execution cancelled." Owm2/ End k 1;Jkq~ End If q%wF=<W 7kQ,D,c' 'Assign accommodation and pupil diameter & use defaults if field left empty d4A3DTW If dlg.TextBox1 = "" Then /G#W/Q A = 0 'Default accommodation /V!gF+L Else Bt"*a=t; A = CDbl(dlg.TextBox1) .;NoKO7) End If X*rB`M7, x DX_s:A If dlg.TextBox2 = "" Then )LE#SGJP pupilDiam = 4 'Default pupil diameter T1fX[R ^\ Else R|dSjE s pupilDiam = CDbl(dlg.TextBox2) vmT6^G End If +yIO 8Nxyc>8K~ Print " " 8!Q0:4Vb Print "Accommodation = " & A & " Diopters" kl9<l* Print "Pupil Diameter = " & pupilDiam & " mm" (JeRJ4 7'TXR[ ' Calculate new parameters with accommodation ]\oE}7K%r taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness nokMS }7/Ob)O Rant = 12.0 - 0.4*A 'Radius of anterior lens [NguQ]B. CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens )\,hc$<=m r2>y
!Q? Rpost = -5.224557 + 0.2*A 'Radius of posterior lens &6@e9ff0 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 4L[-[{2
B,RHFlp{ tlens = 3.767 + 0.04*A 'Lens thickness v9vY#W `jH 0FJQ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction )lB*]
n`Z] Op:7EdT# 'Adjust parameters to account for accommodation 8:t1%O$ >?0 f>I%\ '************************************************************************* 8:4`q9 'Aqueous thickness (Position of Lens) ^W<uc :L7 '************************************************************************* zd#/zUPI eID = FindFullName( "Geometry.Arizona Eye.Lens" ) cLCzLNyKl GetCustomElement eID, entity 9A1w5|X "Kt[jV;6 parID = FindFullName( "Geometry.Arizona Eye" ) 1dX)l d#wK ' Delete any shift(s) in z NpF}~$2 count = 0 Gzu $ While GetOperationCount(eID)>count XP_V GetOperation eID, count, op a+{95"4 If op.Type="ShiftZ" Then ppo\cy; DeleteOperation eID,count B=J/HiwV) count=count-1 OgBZoTT End If @X*r5hjc count=count+1 h; sdm/ Wend B|n<{g[-cM 'Z(4Wuwb 'Set new shift in <IL$8a op.Type = "ShiftZ" FR@##i$ op.val1 = taq B|+tK op.parent = parID wXxk+DV@ AddOperation eID, op 4>xv7 Print "Set aqueous humor thickness = " & taq-0.55 haMt2S2_B: YKs^aQm# '************************************************************************* rC!~4xj- 'Radius and conic constant of anterior lens SgocHpyg '************************************************************************* Oy/+uw^ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 0q
^dpM GetConic eID, entity, curv, conic <sq@[\l}a 9K
F`9Y SetConic eID, entity, 1/Rant, CCant 1p9+c~4l: Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #.n%$r ^zr]#`@G '************************************************************************* t'0dyQ%u 'Radius and conic constant of posterior lens U4@W{P02 '************************************************************************* _GK3]F0 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 5=--+8[ bV GetConic eID, entity, curv, conic ;{Kx$Yt+ 4aQb+t, SetConic eID, entity, 1/Rpost, CCpost 13nXvYo' Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost W!BIz&SY:- m*S[oy& '************************************************************************* zbDM+; 'Lens thickness (Position of posterior lens surface) yy6?16@ '************************************************************************* `?ijKZ}y5 ]}&f<X parID = FindFullName( "Geometry.Arizona Eye.Lens" ) *!*J5/b s) vHLf4 T ' Delete any z-shift(s) @gZ<!g/vza count = 0 C,xM)V^a While GetOperationCount(eID)>count 0FV?By GetOperation eID, count, op f}cz_"o4 If op.Type="ShiftZ" Then d?/?VooU DeleteOperation eID,count 75V?K count=count-1 2$O@T] End If Bld $<uU count=count+1 $3Ct@}=n Wend 6Q._zk |[VtYV _{ 'Set new z-shift ^{T3lQvt op.Type = "ShiftZ" LA.xLU3 op.val1 = tlens r%g?.4o*b op.parent = parID ''f07R AddOperation eID, op Uaho.(_GP Print "Set lens thickness = " & tlens N'nqVYTU }'KVi=qnHb '************************************************************************* )k8=< =s 'Lens index of refraction |6pNe T[ '************************************************************************* 0pS|t/h0 eID = FindMaterial( "Lens" ) c2z%|\q GetModelMaterial eID, mat Oop;Y^gG} oO4
Wwi mat.Nd = nlens bV#U&)| SetModelMaterial eID, mat ^ )Lh5 Print "Set lens index of refraction = " & nlens K`nI$l7hg :A,V<Es}I" '************************************************************************* iTt"Ik' 'Pupil diameter >a;^=5E '************************************************************************* *JX)q eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) [UVxtM J ~O)Uz| 'Adjust pupil diameter (trimming volume inner hole) tj ,*-).4% '|b { SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" $Gs&'
yR D@yg)$;z ' Adjust pupil location to just in front of the lens Ey77]\ parID = FindFullName( "Geometry.Arizona Eye" ) .-;K$'YG eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) *=1;HN3 count = 0 R<gC,eV<= While GetOperationCount(eID)>count u:pdY'`"# GetOperation eID, count, op %:n1S]Vr If op.Type="ShiftZ" Then *Rv eR?kO DeleteOperation eID,count ?=]`X=g6 count=count-1 sD$
\!7:b End If 3,bA&c3 count=count+1 FX"% Wend ,P ?TYk op.Type = "ShiftZ" N7%+n*Z op.val1 = taq-0.01 :z^ps0 op.parent = parID oW-Tw@D AddOperation eID, op @.gT&Hq J_s?e#s Print "Set pupil diameter = " & pupilDiam "aN<3b z0V d(QL 'Update AZ Eye subassembly Description aTs5^Kh') eID = FindFullName( "Geometry.Arizona Eye" ) V#1_jxP)Q GetEntity eID, entity Hw5\~!FX entity.Description = "Accommodation = " & A & "D" K6kPNi SetEntity eID, entity e_+`%A+- PNXZ 3:W Update zh'TR$+\hO Print "DONE!" e|
(jv<~r !Y-MUZ$f End Sub +15j^ Az 5M{N-L_eC 如果屈光度是4,光瞳直径是4,则会输出如下数据: PG9won5_ l/yLSGjM Accommodation = 4 Diopters p8BA an3 Pupil Diameter = 4 mm -9/YS Set aqueous humor thickness = 2.81 iYA06~d Set anterior lens radius = 10.4 and conic constant = -2.375869 -8qLshQ Set posterior lens radius = -4.424557 and conic constant = -3.081019 GEwgwenv Set lens thickness = 3.927 %4 cUa| =? Set lens index of refraction = 1.42672 @QtJ/("&WC Set pupil diameter = 4 EuqmA7s8A DONE! c6s*u%+},
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