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简介 lx |5?P 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。 hB9Ee@ =w$tvo/ 模型 <q
(z>*-e 2o3EHZ+]cm 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 ~j>D=! cc}Key@D Table 1. AZ眼睛模型的定义 DC+b=IOz 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. iD`d99f8O +JRF0T 光源 ~g#r6pzN- :s={[KBP 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 q[3x2sR -d+aV1n 5%zXAQD=< 图1. 光源和提示信息使用 D&G"BZx| 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 7ZxaPkIu&% bWWXc[O2&( 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 "9!d]2.-Vk 1x)ZB~L 图2. 字母F光源的设定方法光 \OILWQ[/ l<g5yYyf 图3. 字母F在视网膜上位置点列图 "_|oW n 视网膜的散射 uo\ .7[1
hRC 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 = ?D(g 8:=n* *NFg;<:j 图4. 视网膜朗伯散射设定 xu5ia|gYz7 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 =Prb'8 W kIHDeo%K} Y;4!i?el 图5. 视网膜重点采样规格设定 6W[}$#w 脚本 Sr?#wev]rn 7?j;7.i
s( 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: gr-9l0u W%<LTWOc 图6. 用户对话框的创建与编辑 E 99hlY~1: 图7. 用户对话框编辑器 MP Z3D9 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#r6b]k(Hv 余下的脚本计算与屈光度有关的所有参数。 >Y7a4~ufko [^CV>RuO 分析 Y3.$G1{#0w q6Rr.A 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 :Z`:nq.a PyVC}dUAX 图7. 字母F在视网膜上颜色分析 m>USD?i 脚本代码 o#) {1<0vg 'c2W}$q Option Explicit 'Remove this to enable non-dimensioned variables to be used. 6+r$t# L86n}+
P\ Dim entity As T_ENTITY gE#>RM5D Dim op As T_OPERATION ,.eWQK~ Dim mat As T_MODELMATERIAL <,o>Wx*1C Dim A As Double 7C#`6:tI Dim pupilDiam As Double ]Chj T} Dim eID As Long :w}{$v}#D; Dim parID As Long \(226^|j Dim count As Integer L,y6^J! Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double sn7AR88M; Dim tlens As Double, nlens As Double QaUm1i# Dim curv As Double, conic As Double 7Q\|=$2 Dim ok As Long 4tL<q_ _zlqtO Sub Main J+rCxn?;g F,
U*yj '用户输入对话框 l/;X?g5+ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 %ZHP2j
%~ TextBox 220,21,40,21,.TextBox1 'default: 0 UOQEk22 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ;iDPn2?6?x OKButton 40,91,90,21 zJe#m|Z CancelButton 190,91,90,21 )`^p%k Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 [MuEoWrq(} TextBox 220,49,40,21,.TextBox2 'default: 4 OL4z%mDZi End Dialog &zs'/xv] Dim dlg As UserDialog @lJzr3}WZ 8r3A~ ok = Dialog (dlg) UK9@oCIB 06jqQ-_`h If ok=0 Then 'cancel button was pressed Uj&W<'I Print "Execution cancelled." d,Y_GCZ7|W End X,9 M"E
2 End If (sVi\R SG6sw]x 'Assign accommodation and pupil diameter & use defaults if field left empty ^vG8#A}] If dlg.TextBox1 = "" Then 9UvXC)R1 A = 0 'Default accommodation ~-wPP{! Else 1lv2@QH9 A = CDbl(dlg.TextBox1) v[Kxja; End If >X*Mio8P# ^eW}XRI If dlg.TextBox2 = "" Then B"%{i-v>** pupilDiam = 4 'Default pupil diameter qzb<J=FAU Else @&[T _l pupilDiam = CDbl(dlg.TextBox2) 0uBl>A7qhn End If `xrmT t
X 1sYEZO; Print " " 42]pYm(jk3 Print "Accommodation = " & A & " Diopters" &=4(l|wcg Print "Pupil Diameter = " & pupilDiam & " mm" JEE{QjTh 610D%F ' Calculate new parameters with accommodation aL\nT XakX taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness J,b&XD@m Wb S4pdA Rant = 12.0 - 0.4*A 'Radius of anterior lens Qt|c1@J CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens y-CX}B#j &w=3^ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens O:da-xWJ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens < y*x]} 7
[g/TB tlens = 3.767 + 0.04*A 'Lens thickness D-,L&R!` IgC}& nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction cV`E>w=D0 6 PxW8pn 'Adjust parameters to account for accommodation 1h.)#g?{ ['ksP-= '************************************************************************* dMrd_1 'Aqueous thickness (Position of Lens) A'nq}t 3 '************************************************************************* j)
,,"54* eID = FindFullName( "Geometry.Arizona Eye.Lens" ) f3UXCp GetCustomElement eID, entity Y6&wJ< 'g9"Qv?0{` parID = FindFullName( "Geometry.Arizona Eye" ) S(7ro]U9 CpJ0m-7aIH ' Delete any shift(s) in z ,\v91 Rp~? count = 0 ~b:Rd{ While GetOperationCount(eID)>count w^]6w\p GetOperation eID, count, op nVJPR If op.Type="ShiftZ" Then S/ibb& DeleteOperation eID,count w4fW<ISg count=count-1 ,6r{VLN End If RN@ctRS count=count+1 ,k G>?4 Wend k#5}\w! 5^j45'%I 'Set new shift in D0BI5q op.Type = "ShiftZ" Iuh/I +[7 op.val1 = taq Y F*OU"2U op.parent = parID rm}
R>4 AddOperation eID, op 1@lJonlF Print "Set aqueous humor thickness = " & taq-0.55 Zy09L}5 9P M2U&?V C! '************************************************************************* 2W$cFC 'Radius and conic constant of anterior lens P bQk<"J1 '************************************************************************* |c`w'W?C6 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) mJM_2Ab GetConic eID, entity, curv, conic +[xnZ$Iev CSCN['x SetConic eID, entity, 1/Rant, CCant r0m*5rd1 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant z'`y,8Y 1l 4WB-Ec '************************************************************************* TB;o~>9U 'Radius and conic constant of posterior lens ^OErq&`u '************************************************************************* ~i.k$XGA eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) $t/x;<.H GetConic eID, entity, curv, conic ?@n/v
F lq"f[-8a2q SetConic eID, entity, 1/Rpost, CCpost nF5qw>t# Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 3 LdQ]S x1ztfJd '************************************************************************* B*gdgM*` 'Lens thickness (Position of posterior lens surface) 8?FbtBAn '************************************************************************* m5Tr-w$QY $m CarFV-T parID = FindFullName( "Geometry.Arizona Eye.Lens" ) [7YPl9 t5lO'Ll*Q] ' Delete any z-shift(s) F H1Z2 count = 0 ]#.]/f
>- While GetOperationCount(eID)>count OnWx#84 GetOperation eID, count, op aC<KN:TN6 If op.Type="ShiftZ" Then *~/OOH$" DeleteOperation eID,count LjU'z# count=count-1 y?SyInt End If .Udj@{ count=count+1 (mlzg=szW Wend `f'K@ WYc7aciJ 'Set new z-shift %e@HZ"V op.Type = "ShiftZ" Y-0?a?q2Fr op.val1 = tlens "U\JV)N op.parent = parID ,<:!NF9 AddOperation eID, op K6olYG> Print "Set lens thickness = " & tlens >s` J5I! cv/_r#vN '************************************************************************* q%5eVG 'Lens index of refraction ykrr2x '************************************************************************* |7#[ (%D! eID = FindMaterial( "Lens" ) B&N/$=5m GetModelMaterial eID, mat Z;h<6[( S(mF%WJ mat.Nd = nlens `EtS!zD~b SetModelMaterial eID, mat @zgdq Print "Set lens index of refraction = " & nlens V
i&*&"q B(F,h+ajy '************************************************************************* KzQ3.)/q 'Pupil diameter *|_"W+JC '************************************************************************* a
{ab*tM eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) .Q)|vq^ fBQ?|~:n 'Adjust pupil diameter (trimming volume inner hole) ^'jEnN( s[gKc ' SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" oBUxKisW 'Z`$n8 ' Adjust pupil location to just in front of the lens RaTH\>n parID = FindFullName( "Geometry.Arizona Eye" ) r",]Voibd eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ?EX"k+G count = 0 X w .p While GetOperationCount(eID)>count ``A 0WN GetOperation eID, count, op ` gW<M If op.Type="ShiftZ" Then >{ me DeleteOperation eID,count |7KeR- count=count-1 *H[Iq!@ End If QKE9R-KTE count=count+1 R<x'l=,D( Wend +ki{H}G21 op.Type = "ShiftZ" fw; rbP! op.val1 = taq-0.01 KgW:@X7wvM op.parent = parID ~r{5`;c AddOperation eID, op ?`[NFqv_] Bb{!Yh].:A Print "Set pupil diameter = " & pupilDiam T}3v(6ew4 P_u|-~|\ 'Update AZ Eye subassembly Description Kq.:G% eID = FindFullName( "Geometry.Arizona Eye" ) rfw-^`&{ GetEntity eID, entity Db"DG( entity.Description = "Accommodation = " & A & "D" 8_K60eXz SetEntity eID, entity
_hG;.=sr M/z}p Update irk*~k ? Print "DONE!" e5Mln!.o ]B=C|usJ End Sub Y
qcD-K u>pBB@ 如果屈光度是4,光瞳直径是4,则会输出如下数据: \Ey~3&x9f 7FO'{Qq Accommodation = 4 Diopters IHC1G1KW=A Pupil Diameter = 4 mm S-#q~X!yJ Set aqueous humor thickness = 2.81 =:+0)t=ao Set anterior lens radius = 10.4 and conic constant = -2.375869 _ q(Q Set posterior lens radius = -4.424557 and conic constant = -3.081019 US{3pkr;I] Set lens thickness = 3.927 iqW1#)3'R Set lens index of refraction = 1.42672 , %YBG1E[y Set pupil diameter = 4 x7T+> DONE! ftBq^tC V,EF'-F (文章来源:讯技光电)
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