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简介 gis;)al ~l"]J'jF"H 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。 V(3=j)# 6>&h9@ 模型 ~X!Z+Vg r: M>/Z/ 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;sZc,Y,^ cZlDdr% Table 1. AZ眼睛模型的定义 ,v$Q:n| 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. \x;`8H ?Es(pwJB 光源 (rm*KD"] 1V:I}~\ 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 ,u_ Z0S M z1S
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?24oO 图1. 光源和提示信息使用 lgQ"K(zY 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 "kd)dy95H h'ik19 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 VMIX=gTZ yXT8:2M 图2. 字母F光源的设定方法光 3>QkO.b o&ETs)n| 图3. 字母F在视网膜上位置点列图 (NC]S 视网膜的散射 Lz{z~xNHW. 7BkY0_KK 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 7!U^?0?/ #g= !
G3Gr 图4. 视网膜朗伯散射设定 1V.oR`&2E 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 @8*lqV2 y4)iL?!J~ A~}5T%qb 图5. 视网膜重点采样规格设定 A<''x'\/ 脚本 Z@,[a Q@KCODi 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: L Q0e@5 GRh430V[ 图6. 用户对话框的创建与编辑 i936+[ 图7. 用户对话框编辑器 T/]f5/ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 %X|u({(zb 余下的脚本计算与屈光度有关的所有参数。 !|Wf
mU rld8hFj 分析 [ylRq7^e 8PR\a!" 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 nvQTJ4,, #/B g5: 图7. 字母F在视网膜上颜色分析 V]NCFG 脚本代码 QQJf;p7 d}Q%I Option Explicit 'Remove this to enable non-dimensioned variables to be used. < 1[K1'7h TJCE6QG Dim entity As T_ENTITY jn(%v] Dim op As T_OPERATION CEW1T_1U<\ Dim mat As T_MODELMATERIAL u4j"U6"]M Dim A As Double s'|t2`K(" Dim pupilDiam As Double X,{ 3_ Dim eID As Long S$ffTdRz Dim parID As Long 2Qt!JXC Dim count As Integer E!_3?:[S_ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double "VDMO^ Dim tlens As Double, nlens As Double u'nQC*iJb Dim curv As Double, conic As Double M|NQoQ8q Dim ok As Long 1yVhO2`7] 2VzYP~Jg Sub Main m*jTvn 1ktxG1"1 '用户输入对话框 2RQ-L Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 }R11G9N. TextBox 220,21,40,21,.TextBox1 'default: 0 e3ce?gk Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 A=3L_
#nO OKButton 40,91,90,21 inip/&P?V CancelButton 190,91,90,21 \W]gy_=D{ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 mRa\ wEg% TextBox 220,49,40,21,.TextBox2 'default: 4 zy5FO<-> End Dialog Q8MIpa!: Dim dlg As UserDialog 3{fg3? f,4erTBH ok = Dialog (dlg) w@<II-9L)< +IO>% If ok=0 Then 'cancel button was pressed m7DKC, Print "Execution cancelled." tj$[szo End @$~IPg[J End If ?w+ V:D Q;J(
5; 'Assign accommodation and pupil diameter & use defaults if field left empty [q Uv|l1 If dlg.TextBox1 = "" Then u~aRFQ: A = 0 'Default accommodation }opw_h+/F Else S'5Zy}
+x A = CDbl(dlg.TextBox1) (|F.3~Amq End If [}]yJ+) 1)MDnODJ If dlg.TextBox2 = "" Then ZP5 !O[Ut pupilDiam = 4 'Default pupil diameter r0 )ne|&Hp Else P:t .Nr" pupilDiam = CDbl(dlg.TextBox2) l<BV{Gl End If 3 ye Rq%Kw> {& Print " " |?ssHW Print "Accommodation = " & A & " Diopters" ?*%_:fB Print "Pupil Diameter = " & pupilDiam & " mm" bi^?SH\ r4fHD~#l{ ' Calculate new parameters with accommodation P.qzP/Ny taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness #K6cBfqI P/dnH Rant = 12.0 - 0.4*A 'Radius of anterior lens 8'HS$J;C CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens V*{rHp{=p [IQ|c?DxpL Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 0'fswa) CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens @J"tM. ~y2zl tlens = 3.767 + 0.04*A 'Lens thickness -X~mW
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Zi[/ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ##*]2Dy 4G?^#+|^ 'Adjust parameters to account for accommodation 6:O<k2=2 m^G(qoZ] '************************************************************************* GD{L$#i! 'Aqueous thickness (Position of Lens) IF|6iKCE '************************************************************************* z.!N|"4yr eID = FindFullName( "Geometry.Arizona Eye.Lens" ) hU8Y&R)=9 GetCustomElement eID, entity &J*M L"NHr~ parID = FindFullName( "Geometry.Arizona Eye" ) <"J]u@|
G$+v |z ' Delete any shift(s) in z b1.*cIv} count = 0 8~]D!c8; a While GetOperationCount(eID)>count B-R#?Xn:!I GetOperation eID, count, op UnF8#~ If op.Type="ShiftZ" Then -juG[zn DeleteOperation eID,count LmePJ count=count-1 DS<1"4 b| End If BzP,Tu{, count=count+1 hlaN'j
<C Wend -f)fiQ-< )ODF6Ag 'Set new shift in rNii,_ op.Type = "ShiftZ" x8PT+KC op.val1 = taq jdP)y]c op.parent = parID jC9us>b AddOperation eID, op 7{L4a\JzT Print "Set aqueous humor thickness = " & taq-0.55 G
@..?> Ki\.w~Qs '************************************************************************* ,erf{"Nh 'Radius and conic constant of anterior lens (~=.[Y '************************************************************************* :TH cI;PG8 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ff\~`n~WZ GetConic eID, entity, curv, conic kI^*
'=: \^c4v\s<o# SetConic eID, entity, 1/Rant, CCant //q(v,D%Q Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant EiL#Dwx z1PwupXt1 '************************************************************************* sjr,)|#[ 'Radius and conic constant of posterior lens =_7wd*, '************************************************************************* }}JMwT
eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) d;Vy59}eY GetConic eID, entity, curv, conic H\67Pd(Z6 `6D?te SetConic eID, entity, 1/Rpost, CCpost Ymk?@mV4 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Ke\\B o, Wwq:\C '************************************************************************* }02`ve* 'Lens thickness (Position of posterior lens surface)
l_vGp '************************************************************************* 7A)\:k ,c p2Fac parID = FindFullName( "Geometry.Arizona Eye.Lens" ) nT6y6F_e EKwQ$?I ' Delete any z-shift(s) 21uK&nVf^l count = 0 :v&[! While GetOperationCount(eID)>count 2$JGhgDI GetOperation eID, count, op /4:bx#;A If op.Type="ShiftZ" Then ,ks2&e DeleteOperation eID,count 1 em,/>" count=count-1 XO <wK End If iC
gZ3M] count=count+1 m&UP@hUV- Wend uJ!&T B$4*U"tk 'Set new z-shift HN5m %R&` op.Type = "ShiftZ" Kg[OUBv op.val1 = tlens {"y/;x/ op.parent = parID Xn6#q3;^| AddOperation eID, op Ys"wG B> Print "Set lens thickness = " & tlens c/;;zc h0GoF A< '************************************************************************* x84!/n^z 'Lens index of refraction 4xy\ '************************************************************************* WE<?y_0y& eID = FindMaterial( "Lens" ) iNO>'7s7 GetModelMaterial eID, mat q2qi~}l $*yYmF mat.Nd = nlens :QE5 7. SetModelMaterial eID, mat oaY_6 Print "Set lens index of refraction = " & nlens NB-dlv1 {ZJO5* '************************************************************************* @T'^V0!-q: 'Pupil diameter Hq3|>OqC2Q '************************************************************************* bjZJP\6 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 7aG.?Ca% Wv;0PhF 'Adjust pupil diameter (trimming volume inner hole) a~$XD(w^ DJP6Z SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" D tsZP
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' Adjust pupil location to just in front of the lens &OMlW_FHR parID = FindFullName( "Geometry.Arizona Eye" ) Wh[QR-7Ew eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 44]s`QyG count = 0 =$>=EBH,cm While GetOperationCount(eID)>count `KJ(. m GetOperation eID, count, op ( xs'D4 If op.Type="ShiftZ" Then i! .]U@{k DeleteOperation eID,count FXQWT9Kk~_ count=count-1 +&GV-z~o End If YW}$e W* count=count+1 \Z-th,t Wend iSW2I~PD op.Type = "ShiftZ" ^_7|b[Bt op.val1 = taq-0.01 }K {1Bm@S op.parent = parID O[@!1SKT0 AddOperation eID, op 9:j?Jvw$ 5E!C?dv(z Print "Set pupil diameter = " & pupilDiam <Xf6?nyZ( })g<I+]Hf9 'Update AZ Eye subassembly Description mypV[ eID = FindFullName( "Geometry.Arizona Eye" ) sS D8Sx/ GetEntity eID, entity aukcO;oG< entity.Description = "Accommodation = " & A & "D" S|85g1}t SetEntity eID, entity +;N]34>S7 ]l,BUf-O Update L^J4wYFTO Print "DONE!" yx-{PjX !3Q0Ahf End Sub c[dSO(= N5Js.j>z 如果屈光度是4,光瞳直径是4,则会输出如下数据: /K=OsMl2b8 x/|W;8g4 Accommodation = 4 Diopters 18&"j 8'm Pupil Diameter = 4 mm *"%TAe7?~+ Set aqueous humor thickness = 2.81 144Y. Set anterior lens radius = 10.4 and conic constant = -2.375869 _`$Q6!Z)l Set posterior lens radius = -4.424557 and conic constant = -3.081019 @rl5k( Set lens thickness = 3.927 Od1\$\4Z Set lens index of refraction = 1.42672 j=WxtMS Set pupil diameter = 4 |OeyPD# DONE! L9b.D<
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